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Quietly, outside of Los Angeles, Steve Trovato has been leaving blazing guitar everywhere he goes.

Currently, he is a full time instructor in the Studio Jazz Department at the University of Southern California. In addition, Steve has found the time to author over 20 instructional books for Warner Brothers and Hal Leonard, produce over 50 instructional videos for the likes of Yngwie Malmsteen and Paul Gilbert, and has even starred in five of them. His students have achieved major success and include Scott Henderson, Frank Gambale, Paul Gilbert and Norman Brown. He has performed with Chet Atkins, Albert Lee, Robben Ford, Jeff Berlin, Jerry Donahue and Scott Henderson, and contributes to five international music publications, including Guitar Player, Guitar One, Axe, Guitar Club, Guitar World and Chittar, as well as recording for too many studio and motion picture projects to list. We caught up with Steve as he completed his new release, Country Jazzmaster.

One of the things I have always wondered about is who or what influenced you to start playing guitar?

Well, I think you’ll hear this from a lot of guys; it was the Beatles. I think I was six years old, and I had been playing the piano. I did my piano recital and played “The Blue Danube Waltz.” Then I saw the Beatles on Ed Sullivan and I thought, “Wow, girls never screamed for me playing piano.” So that was it and I started playing the guitar. That was pretty much it, and I have never looked back.

Did you come across a single moment that it finally hit you? This is it, this is what I want to do the rest of my life?

I’ve never been asked that before; that’s a really good question. I would say that there were three pivotal moments: one of them was when I saw the Beatles, the second was when I heard Chet Atkins for the first time, and the third was when I was up on stage and I got a chance to play with Albert Lee — that was when I really knew I wanted to do guitar. For some reason those guys hit me hard — they played melodies — and I always loved the way I could track it even though it was guitar playing. It was really very sophisticated. When I heard Chet Atkins play, I could hear the melody. Even with all the notes that Albert Lee plays, I can still keep track of it– that’s what attracted me. I think since I’ve been playing, if I have anything, it’s the ability to play a melody.

You’re originally from New Jersey. How did you end up on the West coast attending GIT (now the Musicians Institute)?

Like every guitar player on the East Coast, we were always hungry for information about the guitar. I used to get this magazine and I saw an ad for this place called GIT in California. I saw pictures of Larry Carlton, Tommy Tedesco and other people that I didn’t know, like Don Mock and Joe Diorio, and they were starting this school. They were sort of advertising it being for studio musicians, and that was what I wanted to be.

Now that you already have one CD under your belt, you’ve gone into the studio a second time with some outside input. How are you achieving your tones with the studio?

When I did my first album, I just took my rig into the studio with the thought that if it sounds good live, it will sound good in the studio. I’ve found that not to be true. I also realized that amps that are made specifically for recording don’t necessarily sound all that good in the studio. It really depends on the studio, the mics, and everything else. I brought every amp that I had down there — I even borrowed some amps. I ended up with five or six different amps and I had to just go through all of them to find out which one sounded the best in that studio — with that particular set up of room and microphones. I wound up actually using a boutique amp from a company in Virginia called Talos. I love those amps. It’s a 60-watt, one-twelve, and it just has two knobs on it, drive and gain.

“Well, I think you’ll hear this from a lot of guys; it was the Beatles. I think I was six years old, and I had been playing the piano. I did my piano recital and played ‘The Blue Danube Waltz.’ Then I saw the Beatles on Ed Sullivan and I thought, Wow, girls never screamed for me playing piano. So that was it and I started playing the guitar. That was pretty much it, and I have never looked back.”

What about guitars? Did you find that’s the same scenario to be true?

It’s something I suspected, but I never really had the chance to put it to the test. I usually use my G&L Legacy live, with the Kahler on it because it sounds great. You’re playing loud enough where if there’s a bass, drums and everything cranking you lose the nuances and the subtlety. But in the studio you retain those nuances and subtleties because everything is under a microscope. I found that using different guitars expresses that better.

If I want to play a sensitive, sort of Chet Atkins jazzy piece, the Legacy wouldn’t work because it sounds too thin, but with a loud phrase it will sound fine. For a quiet passage, I decided to use a Gibson — a Howard Roberts with two old humbuckers that I had. Of course, for the Straty-sounding things I used my red Legacy with a Kahler on it, which I absolutely love. For the rest of the stuff I used one of two Teles: a Fender solid body Telecaster and a G&L semi-hollow. None of them are stock. Seymour Duncan custom built the pickups for both of them.

What amps do you prefer for live performances?

I play rock, I use my Dumble. That, of course, is Alexander Dumble. It says “Built to win” and it really does, it’s just really something. I put a pedal in front of it to make sure it’s got enough overdrive. In the country bands I use a ’65 Pro Reverb, which Dumble rebuilt for me.

What do you use on the jazz side?

I use my Talos.

Throughout your time as a guitar player, you’ve been labeled as the chameleon of guitar. Do have a huge arsenal of guitars at your disposal that you have hiding in the back room to take out whenever you need to?

For the live work I pretty much grab whatever is nearest to the front door on the way out. I was never really one to take ten guitars to a session because I figured that one guitar would sound just as good as 10 guitars, but when you really start to do this seriously, there are subtle differences between all guitars that may or may not sound better for the tracks. You really have to have an arsenal of quite a few to do the job right.

What would be an ideal arsenal?

I would have to say you have to have a solid body, Strat-type of guitar with single coil pickups, a single coil Tele-type, a Les Paul-type solid body with humbuckers, a thin semi-hollow body sound, like a 345, and a jazz box, then, of course, steel string acoustic and a nylon string.

You mentioned putting a pedal on the floor in front of one of the amps.

Live I use a Boss GT-6. I use it for time delay effects such as reverbs, delays and chorusing. It sounds great for that and it’s also great on the floor. For distortion I’ve been using the AC Booster and the RC Booster by Xotic Pedals.

The Xotic pedals are fairly new. Can you tell us some more?

Oh, I love them. Those are the kind of the boutique pedals that all the guys in town are using. Scott Henderson told me about them. Studio guys like Michael Thompson are using them. Basically, the RC Booster is a pre-amp boost that keeps it clear, but gives it a little oomph. The AC Booster is an overdrive — basically a really high-end Tube Screamer with a bass control on it. Everybody loves Tube Screamers, but it takes the bass away from it; this is a Tube Screamer that sounds a lot more transparent and smoother than normal. You can also roll the bass back in because it has bass and treble controls.

You mentioned the Kahler Tremolo on one of your G&L’s. What do you like about it?

The thing I love about the Kahler is its flush and mounted solidly on the guitar body, versus another one. I won’t mention any names, but the initials are Floyd Rose. It is not really mounted on the body of the guitar as solidly and or as flush as a Kahler. With a Kahler, the tone sounds pretty darned good. I really like that about the Kahler. Since you have that big plate to rest against the body, you get more natural wood resonance, it doesn’t sound thin and small. The other thing that I like is the adjustable string spacing. I don’t think other bridges can do that.

On the first CD, About Time, you cover a whole spectrum of guitar playing. You do a dedication to Danny Gatton, you’re hitting a little Django, you’ve got “Somewhere Over the Rainbow” from Harold Arlen, and then you even do Billy Joel’s “Root Beer Rag.” What can we expect hear on the new CD?

When I spoke with Steve Vai, he was saying the last CD was really good but I needed a little bit better recording quality. He said the problem with the first CD, as far as marketing, is that I don’t know where to market it stylistically; it’s all over the map. I came up with this concept in my mind called “Country Jazzmaster,” with Jazzmaster being one word, like the guitar. I kept that thread in my mind as I was recording this album, and all of the songs leaned into that concept. Everything that you’re going to hear is country-jazz. Western swing, country jazz — that sort of a thing.

There’s a thread of continuity running through the whole album that you will hear. I recorded everything from the old Jerry Reed tune, “Guitar Man,” to “Back Home Again in Indiana,” “That She Could Ever Be,” “Panhandle Rag” and my ultimate version of “Ghost Riders in the Sky.”

I still remember this vivdly: a NAMM show where you, Steve Vai and I were standing around talking, and Steve hailed you as, “One of the greatest Tele players of all time.” Will we hear evidence of this on the new CD?

That was very nice of him. But, yeah, that’s what I’m hoping for, and I think that it’s really extremely well played, if I can say so myself. We all worked really hard on it.

Trovato Gearbox: Here’s what Steve is plugging in, when it’s time to shine.

Country Gigs

Guitars

• G&L ASAT Tele stock
• G&L ASAT semi hollow body w/Seymour Duncan P90’s

Amps

• Groove Tubes Trio Pre amp
• Groove Tubes 75-watt power amp
• Groove Tubes 2×12 cabinet w/Celestions

Effects

• Boss GT-6
• Keeley Compressor
• Xotic RC Booster
• Xotic AC booster

Rock/Blues Gigs

Guitars

• G&L Fullerton Red Legacy with Kahler and custom Seymour Duncans
• ‘69 Fender Strat (stock)

Amps

• Early ’80s Dumble Overdrive Special
• Two 1×12 Dumble cabinets with Mojo Tone Speakers
• ’65 Fender Pro Reverb with Mercury Magnetics Bassman replacement transformer and 2×12 Mojo Tone Speakers modified by Dumble

Effects

• Boss GT-6
• Maxon Tube Screamer
• Fulltone OCD pedal
• Zendrive Pedal

Steve Trovato: It’s About Time and the new, Country Jazzmaster, are available at: cdbaby.com / myspace.com/stevetrovatomusic

Source: https://mercurymagnetics.com/pages/news/PremierGuitar/PremierG-07.htm

Boy have I got a treat for you guys!!! As you know I am a big fan of Mercury Magnetics transformers and have been a dealer for many years now. Their products are excellent as well as their customer service. The Mercury Magnetics line is quite extensive and they will do custom pieces as well.
I have been working with Sergio Hamernik for almost a year now on an exclusive interview all about guitar amp transformers. In this interview Sergio talks about how transformers affect your amp’s sound and feel, if transformer size matters and how it affects tone, what a choke is and much more information.

Mercury Magnetics is the leader in guitar amplifier transformer manufacturing. I have personally used their iron in many repairs, restorations and custom builds over the years. It never ceases to amaze me when I use a set and listen to the amp after the project is complete. It’s almost like a blanket was taken off of the sound and you are listening with “3D glasses.” The feel of the amplifier becomes much more dynamic as well. In my opinion “your amp’s transformers truly are the heart and soul of your amp.”
In this exclusive interview with Sergio Hamernik (the man behind the scenes at Mercury) some basic questions that all relate to the tone and feel of a guitar amplifier. His answers are forward, straight to the point and insightful.

300guitars: Why should guitar players care so much about the transformers in their amps?

Sergio Hamernik: When a player has to struggle with his amp then there’s really not much of a reason to play it. The tonal quality and performance of a tube-type guitar amp is largely determined by its transformers. Where there is great “tube tone,” you’ll always find “great sounding transformers” making it all happen!

Once you get past the player’s talent/ability, it’s all about the tone. If an amp doesn’t produce desirable tone, the window of inspiration closes and gets replaced with fatigue for both the player and the listener.

These days musicians who choose to play an electric guitar are only as good as their technical awareness and development allows them to be.

Transformers are the most important and most expensive components of guitar amp’s parts list. Also, they are the only components designed and built specifically for that amp, unlike the rest of the components — the resistors, capacitors and even vacuum tubes. These other components are considered to be “universal application” parts — meaning not just for making guitar amp tone. The electronics industry commonly uses these same components for medical, industrial, radio and many other applications. You certainly couldn’t fit or use guitar amp transformers for any of these other applications without offending someone.

Transformers are the key to providing that unique signature tone. It’s the transformers that differentiate one amp brand or sound from another. Here’s another way to look at it — all amp builders have to deal with the same limited choices from a small pool of vacuum tube manufacturers and other off-the-shelf component requirements (resistors, capacitors, etc.). This is NOT so with the transformers. Although there are plenty of generic transformer designs available that service the “power requirements” of an amp, you wouldn’t want to use these awful-sounding devices in your guitar amps. Likewise it’s not a coincidence that most of the best-sounding amp builders, modifiers, and repair techs begin their craft and finish it with enviable distinction, relying on their choice of transformers.

300guitars: Would you explain, in guitar player terms, what power and output transformers are?

Sergio Hamernik: Well, I really don’t like to lump all guitar players into one category. Making assumptions here (be it charitable or not) just doesn’t seem fair to me. Each player has their own level of interest and technical understanding on this subject. So I’ll split my answer into three different groups of definitions and let the player choose the one that suits them best.

In basic guitar player terms: It’s magic!!

In technician terms: A device applying mutual inductance in an efficient manner, so that circuits with different voltage/current requirements can correspond to each other.

In engineering terms: Transformers are electrical devices consisting of a magnetic-core and two or more coils (commonly referred to as windings) inductively coupled as circuits for the transmission of alternating-current energy from one closely coupled coil to another usually at a different voltage and current value. Transformers are also used for matching impedances between the signal generating source and the load.

300guitars: How does the power transformer affect the sound of your guitar? The sound comes from the output transformer right?

Sergio Hamernik: Yes the amplifier’s sound does come out of the output transformer, but where does it all begin? While an output transformer is vital to an amp’s ultimate tone, it simply can’t do it alone. The power transformer is the first step in building tone and in setting the standard of performance that the tubes and output transformer utilizes.

The output transformer depends on the power transformer for determining the maximum amount of power the amp can put out. The power transformer is also a major contributor for the overall feel of the amp. Such as punch through (the oomph factor), note attack, a perceived larger/wider soundstage presence and most importantly, the speed or reaction time of the amp’s audible response to the player’s sense of touch and playing technique. Tamper with that in any way by using cheap “dumbed down” power transformers and your audience may confuse your amp’s tone with the sound that is made by farting into a pillow!

A puny power transformer will deliver puny tone no matter how good the output transformer is. A good output transformer is also not intended to be a problem fixer or a turd-polisher. Garbage in is always garbage out. So please don’t shoot the messenger because the power tranny just ain’t cutting it.

Output and power transformers are actually close cousins. Doing similar tasks, one matches and isolates the speaker from the amp and the other one matches and isolates the amp from the power company. Peace keepers of a sort, preventing tubes from frying the speakers and preventing the power company’s energy from frying the amp and people connected to it.

300guitars: How does the output transformer affect the amps sound and feel?

Sergio Hamernik: An output transformer is the last component of the audio chain. The amplifier’s voice. The final word that reaches the speaker. Because all vacuum tubes were never really designed to distort intentionally, the weight of producing desirable amplified guitar tone falls heavily on the transformers. The output transformer’s job is to coax, extract and even irritate the power tubes into tone-friendly distortion. Ever wonder why solid-state amps have always played second fiddle to tube amp tone? Is that simply because of not employing tubes or of not having an output transformer? At the very least, it’s something to think about.

The output transformer determines how the amp sounds like from fully clean (sweet with a touch of sparkle) to fully over-driven (chainsaw) distortion, and everything in-between.

By the way, the term “clean” as used in guitar amp speak is a bit of a misnomer. There is no such thing as a distortion-free guitar amp. “Clean” simply refers to less distortion. There is an intimate inductive/reactive relationship between the output transformer (coils) and the speaker voice (coils) that also back-washes into the power tubes and influences that “clean to dirty” range of distortion. The quality of the output transformer determines how well the production of tone is executed by the amp — those notes that float between the strings which are created by overtones, chimes, bell tones, sustain, etc. Poorly made output transformers tend to gargle out, squash and mask those overtones.

The output transformer is also responsible for how efficiently the audio power of the amp transfers to the speaker (load). Ultimately, the player issues the final report card for the performance of the amp and the output transformer with comments like “clarity,” “articulation,” “loudness,” “break-up,” “grit,” “glassy,” “grind,” “dirty,” “woody,” “mushy,” “mashed,” “fuzzy,” “dark,” “cloudy,” and so on. There are hundreds of guitar amp speak descriptions and euphemisms out there which capture their emotional response (players and listeners alike) to what is coming out the amplifier’s window.

The mighty output transformer. Loved and hated by so many. Still one of the most misunderstood components of a guitar amp. 80 years and going strong. Go figure….

300guitars: When it comes to transformers does size matter? How?

Sergio Hamernik: I can almost hear my wife saying “now that sounds like a guy question.” Actually, in most situations, transformers and chokes make a good case for “bigger is better.”

A power transformer that is undersized for the job will run hotter than a bitch kitty. The amp is unable to be pushed — collapsing under weak, sagging voltages. It’s unable to keep up with the demands a player puts to an amp. The amp slows and has a tendency to cough out notes when played clean, and honk or bark out the notes when overdriven.

Another symptom of undersized and/or poorly designed power transformers is the phenomenon of “tone drift.” You know this is happening when the amp (common with some early Fenders and half of today’s 100 watt amps) starts off with decent tone for the first hour or so, then somewhere around two hours later the tone begins to change and not for the better. The internal temperatures of the transformer reach their peak and begin detuning the voltages and power the amp sees. This is caused by the changes to the resistance of copper. As the temperatures become excessive, the amp’s tone drifts. Remember rich amplifier tone needs to be well fed.

An undersized output transformer will act more like a suppository to amplified guitar tone than a big open window, which is its main purpose. Contrary to popular myth, there is no tone magic that occurs when you force feed an output transformer into alleged saturation or intentionally under power it with a dinky power transformer.

The term “output transformer saturation distortion” comes out of poor guessing by people who really don’t understand how tubes and transformers work together to produce music friendly harmonic distortion. If an output transformer reaches true saturation, all bass frequencies will disappear, the mid-range will sound dark and fuzzy with lower volume — leaving the treble frequencies tinny and brittle sounding. Does that sound desirable to you?

So it’s not the transformer itself generating that saturation effect on overdriven guitar tone. Good output transformers are designed to operate at low flux densities (loads of inductance). That low flux makes it difficult to saturate an output transformer. So the output transformer doesn’t get the credit or blame for that “saturated” sound. The actual source is in the push-pull power tube plate circuit reacting/saturating to the changing impedance it sees in the primary coil of the output transformer as its flux density changes with the changing frequencies and fluctuating power coming into it. The saturation phenomena (when it appears) is mostly happening in the tube.

If one wants to intentionally use a dinky power transformer to achieve tone magic (yes some have tried it, believe it or not). They could save themselves a bunch of money and buy that pillow I mentioned earlier for similar results.

Bigger is better for chokes if you have the room for it on the chassis. Assuming the same value of inductance, more iron and copper will let more power through and it will run cooler as well. This is because of lower DC voltage resistance with the extra copper involved. More voltage being available to the tubes means more power out of the amp.

300guitars: What is the choke for and why do you offer so many models?

Sergio Hamernik: Originally chokes were used in guitar amps to extend the life of vacuum tube rectifiers nearly tripling their life expectancy. They behave as a quasi current spike shock absorber. Chokes help capacitors smooth out any ripple that may be present on the DC voltage. The goal here is to always try to get the cleanest voltage to the tube circuits. Caps by themselves do a pretty job of it. But the choke is a multi-tasker. Along with doing a nifty job of smoothing out ripple, the choke does something else that makes it a significant contributor to the amp’s final tonal character. Because its connected in series with the rectifier and not tethered to ground like a cap, the choke (being an inductor) works nicely as a current regulator. And it keeps the current from decreasing as much as it would if there were only caps involved.

This nearly constant current available from the power supply, courtesy of the choke, makes for an ideal platform to make the best possible tone. Simply put, changing the value of the choke changes the tone and behavior of your amp.

Why so many varieties of chokes? Since chokes are a significant link in the audio chain, a one size fits all approach would be a great injustice to all guitar amp owners. Choke values are a finesse point, a fine tuning that helps to extract the most favorable tonal characteristics from an amp. We even offer a “shift on the fly” option with our multiple-value Multi-Chokes. One choke with several choices of inductance to help the amp builder find that sweet spot.

There is one last benefit to using chokes and it’s the most overlooked attribute. When a choke is connected between a couple of caps, a form of a low pass filter is created. What this means is the choke blocks high frequency garbage on the AC line from mixing with the guitar signal and causing all sorts of sonic collisions during the process of amplification. Let us not forget that we live in an electronic age far more complicated than the 1950s or 1960s. There are all sorts of things contaminating our power before it hits our amps. Computers, TVs, BTL cable services superimposed on our power lines, you name it, are all sources of noise we don’t want in our amps.

You’d be surprised to find out how many amp builders substitute a resistor for a choke just to save a few bucks and lose out on the choke’s very cool advantages. Almost all of the great vintage amps had chokes (Marshall 50 & 100 watt, Vox AC30, Fender Twin, Showman, Super Reverb, Vibroverb, Pro Reverb, Deluxe Reverb, etc.). The builders back then were taught tube theory and understood the relevance of the choke in their designs.

300guitars: Would a Mercury replacement reverb transformer make the reverb in an amp sound better?

Sergio Hamernik: That depends on how lousy the original one was. Reverb transformers are wound similar to guitar pickups. Lots of turns with very thin wire. Which adds to the expense of building them. Many companies skimp on materials to keep their costs down as a result.

We believe that the low level signal (barely a whisper) going into the reverb transformer is quite fragile in nature and anything less than using the best materials and winding techniques would cause it and its tone harm. According to our customers that have upgraded their reverb transformers with ours, they report better performance, higher def, a more lush-sounding reverb, etc. Based on that, my answer is yes — or your money back.

300guitars: Is it easy to upgrade an amplifier to a set of Mercury transformers?

Sergio Hamernik: Heck no! It’s not at all easy. Therein lies the rub. This is why we have the great divide between disappointing “corporate” tone and a thriving (yet inconsistent) boutique amp market.

How much hassle and expense are you willing to put up with to get your ideal tone? If merely swapping out tubes will improve tone, then why are we still missing so much of it today? If simply plugging things in or out made for better tone, then all the big amp companies would have nailed it decades ago and we wouldn’t have the need for this interview. But no, it’s not that easy. Quick, cheap and dirty (non-transformer) amp fixes are not worthwhile timesavers. They tend to act more like tinsel and don’t do much for real tone problems. My wise old grand dad once said, “Putting powdered sugar on a turd, doesn’t make it a doughnut.”

Upgrading to Mercury transformers requires technical expertise and a morbid fear of being electrocuted. There are potentially lethal voltages present, a ship load of wires coming out of these things to further complicate matters and requiring a good share of installation elbow grease to boot. A person should be schooled in electronics and not sexually frustrated. A steady hand goes a long way in doing a good install. It shouldn’t be a D.I.Y. project no matter how simple it may look to the casual observer. We have techs all over the planet that are willing to help and do a good job with safety first. Transformers are expensive and labor intensive to install.

Those who are ready to make such a commitment/sacrifice (who needs kids anyhow?) will be rewarded for their efforts. Don’t take my word for it, just read our testimonials. We have a bunch of them all unsolicited from players, amp builders and amp techs, who were impressed enough to write to us telling everyone that it was well worth it.

300guitars: It seems that tubes and big hunks of iron (transformers) are very old school technology. Is there anything new on the horizon at Mercury?

Sergio Hamernik: Playing a guitar is even older school. There isn’t anything modern about an electric guitar. But, what makes an electric guitar “electric” is the fact that it depends on the rules of magnetism. The pickups on an electric guitar are made of coils of wire responding/reacting to a changing magnetic field, so are the voice coils in speakers. And let us not forget the power transformer, choke and output transformer in an amplifier are doing their jobs through magnetic fields — literally completing the link between a player’s finger tips to the player’s and listener’s ears.

My point being that if you replace your amp’s transformers for something else, you might as well replace the electric guitar with something else. So happily, we’ll stay stuck with big hunks of iron and hang on to our electromagnetic guitars! This means that tubes, which are not magnetic devices, could eventually be replaced by other devices such as high-voltage Field Effect Transistors as long as they’re mated to right kind of transformers. This is stuff that you don’t really need to know, but it’s a point of interest. There are a lot of motivated people out there that are fed up with the poor quality of tubes today and might be able to make tube substitution a reality someday soon I hope.

What’s new on the horizon at Mercury? A bunch of stuff. A cool new line of transformers that will give the next generation of players a unique voice of their own. Vintage is great, but we also want to encourage a new generation of inspired song writers and players to continue guitar based music. It’s all about the tone that will help seed this.

We are in the process of designing, developing new Upgrade Kits, pre-packaged transformer sets for those who are not satisfied with the tone of their present day amps. It’s our passion.

And, possible amp tone clinics. If that is what players want. We are also working on things that are a bit beyond the horizon which I’ll talk about sometime later.

300guitars: Thanks Sergio for taking the time for this most informative interview!!!

Sergio Hamernik: Thanks Billy for this interview and for giving a damn about all this stuff we call tone. Your passion clearly shines through on your website. It’s people like you that keep it all going and compel us to continually raise the bar for the guitar playing community.

I also want to apologize in advance if I offended anyone’s sensibilities with any comments I may have made. I will learn to live with the guilt….

Source:  https://mercurymagnetics.com/pages/news/300guitars/300g-02.htm

Shop for Amp Transformers

By Billy Penn

The term “imitation is the sincerest form of flattery” has particular meaning in the music industry, where popular guitars and amplifiers have long been used as templates for the creation of “new” brands. This is particularly true in the boutique amplifier market, where probably 99 percent of currently available models are based on classic designs by Fender, Marshall, and Vox. Given that reality, it’s inevitable that some of the more recent amp builders who have managed to innovate and create truly original sounds will also see their designs cloned to one degree or another. The raison d’etre for copycat products is typically that demand for the real thing outstrips the supply, or that relatively few can afford to purchase the authentic product. Both are true of the amplifiers made by Howard Dumble, and the fact that the vast majority of guitar players will never get closer to one of his Overdrive Specials than the front row seats of a concert makes it no surprise that a small number of builders offer their own takes on that extremely rare and expensive amp (we’re talking around $30,000 these days). One of those is Fuchs Audio Technology, which with its Overdrive Supreme (a name that can also be conveniently abbreviated as ODS) makes no attempt to conceal where it draws its inspiration.

But Fuchs has packed plenty of cool things into this amp that any tube freak could appreciate. A peek inside the aluminum chassis reveals a mix of neat handwired and PCB circuitry, chassis-mounted pots, jacks, and switches (the mini toggles reside on one of the three PC boards), and chassis-mounted sockets for the four Svetlana 6L6GCs, two Ruby 12AX7As, and two Groove Tubes GT12AX7Ms. For low noise, the tube filaments are heated by regulated DC voltage, and regulated high-voltage supplies the preamp stages. The fan-cooled amp sports a high-quality Mercury Magnetics output transformer, and biasing adjustments are facilitated by the addition of bias trim pots and test points for each output tube.

Controls

Not that the Overdrive Supreme is overly complicated, but a few of its functions warrant explanation. In basic terms, this amp consists of Clean and Overdrive channels (or preamps), both of which feed a common set of tone controls, a reverb, and a Master volume. The Gain knob adjusts the amplification level in the Clean preamp, which in turn feeds the Overdrive preamp when you switch to distortion mode. Then there are three Overdrive controls: an internal (but user adjustable) trimmer that determines the amount of signal flowing from the clean preamp into the first stage of the Overdrive preamp, an Input knob that sets the amount of distortion (by adjusting the drive level between the two pairs of overdrive stages), and an Output control that’s essentially a lead master volume. This combination of controls gives you the ability to precisely tailor the amp’s gain stages to suit your guitars, pickups, and playing style.

The Overdrive Supreme also has a number of switchable functions that affect its tone. The Brite switch operates on the Gain control to provide a boost in treble (which diminishes in effect as the knob is turned beyond the halfway point), the Deep switch shifts the overall tonality of the amp to emphasize lower frequencies, and the Rock/Jazz switch alters the range and depth of the tone controls to provide for more gain and a more aggressive EQ in the Rock setting, or a smoother, more neutral response in the Jazz position. There’s also a Mid-Boost pull function on the High control that shifts the range of the circuit to emphasize midrange and a Gain-Boost pull function on the Mid control that bypasses the tone controls to increase gain on both channels. Lastly, turning up the Accent control reduces negative feedback at higher frequencies in the power section to increase edge and sustain.

Supreme Tones

Auditioned with several different speaker setups (including Marshall 2×12 and 4×12 cabs and a Celestion-loaded Dr. Z 2×12), the Overdrive Supreme never failed to impress. The closed-back Dr. Z cab worked particularly well with this amp (the cab’s width was a perfect fit too), and Fuchs also offers a matching 2×12 loaded with Fuchs FAT-1S speakers ($695 retail/street N/A). But even driving two 12s, the Overdrive Supreme is a loud amp that seems to find its “sweet” spot at levels that would be overkill in a small club. You can tame the blast with the Master Volume, but as this amp struts its stuff best when let off the leash, you might want to consider one of the lower-wattage Supremes if you don’t regularly gig on big stages (head and combo configurations are available in power ratings from 30 watts to 150 watts, and at prices starting at $2,395).

In its cleanest mode with the Rock/Jazz switch in the latter position, the Overdrive Supreme delivers crisp clean tones to the limit of its output stage. If you like to play clean at high volume, this amp does the trick. These tones sounded great with a Strat, though humbuckers also elicited a good degree of sparkle, as I discovered when playing it with a new PRS 12-string. The reverb is smooth and pleasing throughout most of its range, though the higher the setting, the more detached the effect seemed to become from the notes. I couldn’t obtain any sproingy surf textures either, even with the Reverb knob turned all the way up, but Fuchs probably intentionally voiced it for more “hall” and less “beach.” Interestingly, when the effects loop is set to Series mode with nothing connected to the Send and Return jacks, all you hear is output from the reverb tank. You either need to have a device in the loop for serial operation, or keep the switch in the Parallel position, which you’ll probably want to do anyway if you’re using a delay or a digital reverb.

Switching to the Overdrive mode, the Supreme delivers soaring lead tones that are ballsy and articulate. I had no trouble obtaining massive distortion from a Strat and a Tele, and even without kicking in the extra gain boost there was no shortage of creamy “forgiveness” in the dynamic response. Pegging the Gain knob is necessary for obtaining maximum grind from this amp, but the cool thing is, when you switch back to Clean mode the sound is dead clean. I didn’t notice any significant tonal difference between the Deep switch settings, but activating the Mid Boost fattens up the sound of single-coils quite effectively. The Overdrive Supreme has a strong midrange presence anyway, a quality that allows it to cut amazingly well in a loud band. (In fact, one tester reported being able to hear this amp clearly from the opposite side of a large stage, even when standing right in the blast zone of the other guitarist). The Overdrive Supremeis also louder and definitely more aggressive with the Rock/Jazz switch in the former position.

It’s very easy to get carried away with the sheer amount of distortion that’s available in Overdrive mode, however, by backing off on the Gain and Input knobs, it was possible to get killer medium-grind tones reminiscent of a cranked Fender Deluxe’s. This is a perfect mode for loud blues playing, especially with that output stage ready to leap into action like a cornered tiger when you dig in with your pick.

Supreme Court

There’s enough to like about the Overdrive Supreme that one can almost forgive its four-button Artist footswitch (an essential item that costs an additional $395; a standard 2-button switcher is no extra charge), which has a rather generic housing, label-machine stickers to ID its functions, and uses a fairly stiff type of high-tech cable with a multi-pin connector on the amp end — don’t count on an easy replacement if this baby fails in the field. (Fuchs states that the footswitch is being revised, and will have an aluminum bezel to replace the stick-on lettering.) A hip thing, however, is that its large LEDs are so intensely bright that you’d likely have no trouble seeing their indications even when playing at noon on the Bonneville Salt Flats.

The Overdrive Supremehas that rare quality of being able to draw you in immediately, yet continue to reward and inspire you the more you play it. Considering what it’s based on, it would be a surprise if the Overdrive Supreme wasn’t an impressive amp.

Those of you that have been with us for a while are already familiar with Jeff Bakos and Bakos Ampworks. Frankly, we would have a hard time doing what we do here without Jeff’s presence, just a few clicks west of Ponce de Leon Ave. After 15 years or so repairing, restoring amps, engineering recording sessions in his studio next door, and weathering the ‘80s and much of the ‘90s as a working bass player in a variety of bands, his enthusiasm for great tone remains undiminished.

In his spare time, when one of his customers expresses interest, Jeff has recently been building his own take on a tube-rectified Marshall JTM45. The character of the early JTM45 amps is a little more forgiving and less aggressive than the plexi and metal panel models, and this is accurately captured in the Plus 45. Like the Blankenship, the voice of the Bakos is rich, round, full and exceptionally musical, enhanced with thoughtful features developed after years repairing and tweaking hundreds of vintage Marshall amps. Jeff also built a custom version of the Plus 45 using the preamp section of a Gibson GA40 with interesting results, and both models are reviewed here. While skeptics won’t resist suggesting that we may be incapable of objectively reviewing an amp built by someone with whom we have an ongoing relationship (a member of our advisory board who also fixes our amps), we’ll assume you are better than that. Nothing gets reviewed here that doesn’t earn the ink. We asked Jeff to describe how the Plus 45 was conceived, and our review follows….

JB: What I wanted to do was build a more versatile version of a tube-rectified 45 watt Marshall. I experimented with a lot of different capacitors, tubes, transformers and front panel control features, and I would up choosing to include a switchable master volume and a tone mid-boost.

TQR: But you didn’t use the early Marshall master volume circuit….

JB: No, I used the version that is found in Orange amps and Matchless that works from the phase inverter. It’s an easy one to bypass, and it sounds good until you get below 3-4 on the volume control.

TQR: What were you chasing tone-wise?

JB: Well, originally Marshall used KT66s, and having played a lot of Marshalls, I thought the tone was better with EL34s. They seem to produce a better bass response without being too woofy, and the EL34s have some sparkle in the top end that the KT66 slack. And the Mercury Magnetics transformers selected operate at higher plate voltages that give you more head-room, cleaner tones, and even a cleaner kind of distortion. And unlike many of the early Marshalls, the tone controls really work in the way they exert an audible effect on EQ rather than everything being so notched in the mids. The old Marshall inputs were either super bright or too bassy, so I played around with the cap values on the inputs to make them more usable and versatile. It’s a combination of higher plate voltages, the output tranny design, EL34s, the master volume mod, and tweaking the cap values for each channel so that you aren’t stuck with the original dull and super bright tones in the two original channels. I also use Sozo caps, and they have a very vintage sound. It’s the sum of the parts…. I also changed the pot value for the presence control, and I added a push/pull mid range boost. It’s a very pedal friendly amp, too, because it has a lot of headroom.

TQR: What types of tubes did you choose?

JB: SvetlanaEL34s, a Chinese (Ruby) 5AR4 and a couple of EI12AX7s and a JJ. The Svetlanas have a nice mid range character where some of the others sounded a little flat.

TQR: And speakers?

JB: The Avatar Hellatone G12H 70th Anniversary seems to be really good for the combos. Great low end and very balanced and round.

TQR: And then you began experimenting with Mark Johnson’s amp, who plays busted up slide in mostly smaller venues, and the stock Plus 45 was too clean….

JB: Yeah, I toyed with the idea of building a front end using 5879 preamp tubes similar to a Gibson GA40. It sounds really good – it has a lot of high gain and it gets there really quick.It’s dynamically very responsive, and of course, far more powerful than the originalGA40… you can hear the 5879 sound with lots of gain, but with more headroom behind it.

TQR: If someone asked for a Plus 45, but with a higher or lower threshold of clean headroom, can you do that? How flexible can you be?

JB: This Bassman circuit does give you some room to work with different rectifiers and cap values, but it’s already the cleaner side of a vintage Marshall, which makes it very pedal friendly, and the gain is there when you need it – you’re just not stuck or locked with it.

TQR: What’s next? You’ve mentioned building a black-face Deluxe and the Gibson GA40.

JB: Well, I own a lot of amps and I’m inspired by them all in different ways, but yeah… what to build? Given the parts availability we have today with chassis, cabinets and transformers, building classic designs and modifying them to taste is where it’s at. I’m open to building whatever people wanton a custom basis as time permits

The “stock” version of the Plus 45 (no GA40 preamp section) reveals a strong amp with much more headroom and articulation than you’d normally associate with an early Marshall design. Features include two individually voiced channels, master volume, treble, mid, bass, presence and mid-boost. Channel 1 (bright) played with a Strat at moderate volume levels is almost Fender-clean, but stops well short of sounding too thin or sharp. What it does add is a sparkly, tactil equality to the treble tones that you’ll never squeeze from a vintage Marshall… with the mid-boost on, the tone becomes thicker with a subtle increase in sustain, yet string definition and note separation remain clear and undiminished. Channel2 is chunkier, but nothing like the dull and bassy 2nd channel in a 4-input vintage Marshall. You’ll use this one liberally without jumping it with the bright channel.

The Plus 45willingly responds to stronger pickups like hum-buckers, Telebridge and P90s with a formidable presence that dwarfs more modestly powered amplifiers, producing rock solid lows, fat and politely forward mids, and a smooth treble character that hangs tough in complex chords and single string solos. Best of all, it’s easy to move from clean tones a tan audible stage volume to varied levels of distortion and sustain intensity from the volume control on your guitar –channel switching not required. If you don’t require and can’t handle a 45 watt amp, we understand, but nothing hangs fire like big iron, and the Plus 45fills a room with thundering tone that cannot be rendered from 20 watts. In fact, it reminds us more than a little of the tube-rectified 1961 blonde Bassman 6G6 reviewed in the April 2007 issue of TQR. The master volume nimbly attenuates volume from settings above 10 o’clock with a tone that is slightly thinner than the natural over driven sound of the amp at the lower set-tings, but the results are good and definitely usable, with none of the weak, fizziness you may have experienced with other master volume circuits.The Plus 45 with GA40 preamp section is an entirely different beast, with a lower threshold of clean headroom and much faster ramp-up into a hot meltdown compliments of the dual 5879 preamps tubes. Basically, it sounds like a 45 watt GA40 that naturally mates well with single coils. With more powerful humbuckers, we had to pull a large part of the bass EQ out of the signal lest we blow up our precious Celestion Alnicogold speakers (or so it seemed). The GA4 0version of the Plus 45 is no plaything – a serious appliance for players who want to make a lasting impression. Jeff can voice this amp for more or less bass and treble response based on your preferences, band like the original Plus 45, you can choose between a head, 1×12 or 2×12 combo.

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We always maintain a steady flow of gear arriving for review, but sometimes we also employ a fascinating if time-consuming research strategy that involves logging onto eBay, picking a broad category such as “guitar amplifiers,” and settling in for as long as it takes to patiently scroll through every page of listings. Yeah, that’s often 50 pages or more, but since we can’t possibly think of all the items that might interest us and search for them by name, it’s far more revealing and productive to just hunker down and scroll. Rarely do we fail to find something intriguing that would have otherwise been missed, and such was the case on a morning in August when we stumbled on a listing for a 1959 tweed Deluxe. Were we looking for a tweed Deluxe? Nope. Wouldn’t have crossed our mind at the time…. We had already reviewed 5E3 reproductions from Fender, Clark and Louis Electric within the past 3 years, and we have frequently referenced our 1958 Tremolux as being our desert island #1. Isn’t a Tremolux just a tweed Deluxe with tremolo in a bigger box? No… not even close. That would be like saying you wanted to date a blonde – any blonde. For the record, our fixed bias Tremolux possesses a cleaner tone with a bigger, booming voice created by the taller Pro cabinet. The Two Fifty Nine is a completely different animal….

Sporting a February 1959 date code on the tube chart, the ’59 had been listed by a seller in Arkansas who turned out to be Tut Campbell, formerly a well-known guitar dealer in Atlanta. Still buying and selling gear, Campbell had described the Deluxe as being in original condition with the exception of a replace output transformer – a big old mono block Stancor dating to 1957. Given the otherwise original condition of the Deluxe, which included the Jensen P12R, we made Campbell a “best off” below his asking price and scored the amp for $1,850 shipped. We wouldn’t say we stole the Deluxe, but it seemed a fair price of admission for the opportunity to experience and explore still another rare classic and supremely worthy piece of Fender history on your behalf.

The Deluxe arrived with the big Stancor dangling from the chassis despite Campbell’s careful packaging. Wasn’t his fault, really – in a feeble effort to avoid any additional holes being drilled in the chassis, the fellow who installed the Stancor in the ’60s had merely tightened set screws over the small tabs at the base of the heavy tranny, which was designed to be mounted upright – not hanging upside down in a guitar amplifier. Of more concern was the fact that while the amp was lighting up, there was no sound…. Well, we’ve been here before, so we made a call to God’s Country and the Columbus, Indiana domicile of Terry Dobbs – Mr. Valco to you. We had already set aside a spare output transformer (Lenco, McHenry, IL) that had been the original replacement installed in our ’58 Tremolux when we first received it, replaced with a Mercury Magneticsfor our June ’07 review article. Mr. Valco cheerfully answered his phone and as we explained the situation with the Deluxe he agreed to walk us through the installation of the new replacement – a simple process involving four lead wires being connected to the rectifier and output tube sockets, and the speaker jack. As long as you put the correct wires in the right place, a piece of cake, and we had the new tranny in within 10 minutes. Pilot lamp and all tubes glowing, still no sound…. Valco patiently guided us through a series of diagnostics with the multi-meter and the Deluxe was running on all cylinders, pumping 380 volts. Stumped, and with the hour growing late, we called it a day. Leaving the mysteriously neutered Deluxe chassis on the bench until tomorrow.

Morning came with a whining voice delivering a plaintive wake up call – “It’s got to be something stupid and simple….” Inspired by a huge steaming mug of Jamaican High Mountain meth, we sat back down at the bench, tilted the innards of the Deluxe chassis forward beneath a bright halogen desk lamp and peered in for answers. We began slowly examining the chassis in sections, looking for broken or dull solder joints, loose or broken wires, while gently pushing and prodding wires and connections with the eraser tip of a #2 pencil as we had seen Jeff Bakos do so often at his bench. After ten minutes or so we were about to give up, when we turned our attention to several places where the circuit was grounded to the chassis adjacent to the volume and tone pots, and damned if a solder joint for one of the uninsulated ground wires hadn’t separated from the chassis. No ground, no sound, and as soon as we had restored the solder joint the Two Fifty Nine arose from the dead with a mighty A major roar.

The amp was indeed remarkably well-preserved in all respects, with the typical amber patina of old tweed. The burnished chrome control panel remained bright and clean with no corrosion, the original handle remained intact, and a couple of small ciggie burns on the edge of the cabinet added a stamp of historic legitimacy to the Deluxe’s pedigree. The top half of the Jensen’s frame was coated in a fine film of red clay dust from the Delta, and while the cone was in remarkably good shape with no tears, an audible voice coil rub called for a recone. We would send the speaker to Tom Colvin’s Speaker Workshop in Ft. Wayne, Indiana, requesting that he leave the original unbroken solder joints for the speaker wires intact if possible.

Meanwhile the first order of business was to listen to an assortment of NOS tubes from our stash, and audition no less than a half dozen speakers. Different sets of power tubes and individual preamp tubes will sound surprisingly different, so we started out with a matched pair of NOS RCA 6V6s, a GE 5Y3 rectifier, and an RCA 12AX7 and 12AY7. From there we subbed in a dozen different RCA, Amperex, Tesla and GE 12AX7s, noting varying levels of brightness, warmth and intensity among them all. For an edgier, more aggressive voice, the GEs and Amperex typically deliver the goods, while RCAs produce a slightly warmer, richer, fuller tone. We also experimented with a 12AT7 and 12AX7 in place of the lower gain 12AY7, and while those tubes ramp up gain and distortion faster and with more intensity than the 12AY7, they seemed like overkill for us. Our Deluxe possesses a tone of gain using the stock 12AY7.

Rather than repeatedly reloading the Deluxe with different speakers, we used a Bob Burt 1×12 cabinet built from 100-year-old pine for our speaker tests. The original Jensen had never been pulled from our amp, but multiple speaker replacements in an old Fender inevitably cause the speaker mounting screws to loosen in the baffleboard, making speaker swaps unnecessarily clumsy and complicated. When we do run into loose mounting screws, we simply run a few small drops of Super Glue around the base of the screw and surrounding wood. Allow to dry and your screws will stay put provided that you don’t torque the nuts on the mounting screws like an idiot with a socket wrench. Don’t be that guy,

We tested a range of speakers that included a Celestion G12H 70thAnniversary, Colvin-reconed ’64 Jensen C12N, Eminence Wizard, Private Jack, Alnico Red Fang, Teas Heat, Screaming Eagle, Red, White & Blues, and Warehouse Green Beret, Veteran 30, Alnico Blackhawk and Alnico Black & Blue. The Alnico speakers generally produce a tighter, smoother, slightly more compressed tone, with a variable emphasis on upper mid-range and treble frequencies, while the speakers with ceramic magnets possess a wider, more open sound. Higher power ratings of 75W-100W offered by the Red, White & Blues, Screaming Eagle and Warehouse Blackhawk typically translate into more graceful handling of bass frequencies, and in a 20 watt Deluxe, zero speaker distortion, for a clean, powerful voice.

Let’s cut to the chase with speaker evaluations, shall we? It has become clear to us that even after reviewing a dozen speakers in as much detail as mere words allow in a single article, many of you remain uncertain about which speaker to choose. No kidding. We would absolutely love to hand you a single magic bullet when it comes to speaker swaps, but here’s the dirty little secret about choosing speakers…. The overall character of the amp you will be installing your new speaker in is critical, and to some extent, the type of guitars and pickups you play most often are important, too. Tailoring your sound with the unique gear you play is not a one-size fits-all proposition – you have to invest some thought into the process. Are you going for a classic “scooped” American Fendery tone, or something more British, with a bit of an aggressive edge and upper midrange voice? Are you playing guitars with single coil pickups or humbuckers? Is there a specific, signature tone you are searching for, or are you playing a wide variety of musical styles that requires a broader range of tones? Do you like the more open sound of speakers with ceramic magnets, or the smoother compression of Alnico? What are you not hearing from your amp and the speaker that’s in it now? Do you want a brighter tone, darker, better bass response, or fuller, more prominent mids? Do you want to really drive the speaker and hear it contributing to the overdriven sound of your amp, or do you want a big, clean tone with no speaker distortion in the mix? The truth is, if you don’t know what you want, you are far less likely to get it. On the other hand, nothing is accomplished with paralysis by analysis. To be perfectly honest, there are lots of speakers made by Celestion, Eminence, Warehouse and, if you can wait long enough for them to break in, Jensen, that we could and would be perfectly happy with, but we would also choose them carefully, taking into account all the factors mentioned above. After a couple of days spent swapping speakers, we ultimately concluded that we preferred the ’64 C12N for a classic tweed Deluxe tone, and a broken-in Celestion G12H 70th Anniversary for the most mind-altering 18 watt Marshall tone we have ever heard. Seriously. More on that in a minute….

Having split more than a few hairs with our speaker swaps, it was time to start picking nits off of gnats with some output transformer evaluations. We first contacted Dave Allen of Allen Amplification, who also stocks Heyboer transformers built to his specs. We found a variety of appropriate output transformers on Allen’s site that offered subtle variations on a stock original Deluxe OT, and we asked Dave to describe the TO26 model we wished to try in the Deluxe:

“The TO26 was intended as a hot rodding upgrade to a stock Deluxe Reverb OT. While maintaining the stock 3-1/8” mounting centers, its fat stack of hotter core steel and multi-tap secondary make it a good choice for builders wanting to maximize the performance of a pair of 6V6s and who may also want to push the envelope with 6L6/5881s while still being able to clear the speaker in a stock cabinet. There are physical limitations in small amps, so its short low profile is welcome. The orientation of the laminations is also good for low hum pick up from the power transformer. I found that an OT mounted the tall way (like my TO30D) picks up considerably more hum simply due to its orientation to the power transformer, so, shoe-horning a ‘tallish’ OT into your amp may cause it to pick up hum from the power transformer – not much of an upgrade. “The TO26’s 7K to 8 or 16 ohm rating makes it ideal for a pair of 6V6s as well as 3,500 ohm to 4 or 8 rating for 6L6/5881s. Notice you always have an 8 ohm option with both types of power tubes. An impedance switch could be wired (I use a blackface grounding switch) as a power tube type selector for an 8 ohm speaker to go between 6V6s and 6L6s. The TO26 will typically give slightly more output with 6V6s due to its more efficient low-loss core steel and will keep the bass clean longer for more perceived clean headroom. As it takes the most watts to reproduce the bass, you notice distortion there first, and since Fender-type amps are so bass heavy, you can quickly hit the wall with headroom, so a noticeable increase in clean bass response certainly feels like a more powerful amp with the TO26. It is kind of like you installed a new speaker with a larger ceramic magnet that is more efficient than the old speaker. The amp is a little louder and the bass a little tighter or cleaner.

“There seem to be a lot of 6L6-based 5E3 amps out there now to get a little clean headroom from a circuit normally not known for much of that. The TO26 is a good choice for that type of amp as it will fit typical available chassis and cabinets. It has extra long 12” topcoat leads ready to strip and solder. I would reckon it would handle up to about 30 watts before starting to saturate and compress – plenty of cathode-biased 6L6s. I find that the Heyboer paper stick-wound and interleaved output transformers with premium core steel and heavy core stacks have typically better clarity or definition than ‘stock’ OTs. Call it fidelity or whatever you want – just clearer distorted and complex tones and better separation of notes in chords, etc. I use the TO26 in the Allen Sweet Spot, Accomplice Jr. and Hot Fudge with Nuts amps with excellent results. All of these amps can use either 6V6 or 6L6 power tubes. You know how a 5F6-A or Super Reverb has that huge 4 bolt OT for a pair of 6L6s to get the maximum clean bottom end? That is sort of what the TO26’s OT is to a pair of 6V6s. It just doesn’t even come close to saturating.

When we informed Dave that we planned to run the Deluxe with 6L6/5881 power tubes as well as 6V6s, he recommended that we try the TO26 since it had been specifically designed for such applications. He also sent a smaller TO20 transformer, described as being designed with a wider 1-1/4′′ lamination “fat stack” that provides 60% additional core mass than typical ¾′′ stack units for improved performance. The TO20 is a direct replacement for Blues Jr. and Princeton Reverb amps, and also suitable for dual EL-84 amps with an 8 ohm load.

Mr. Valco also sent us a replacement 5E3 output transformer he had bought on sale from Clark Amplification a few years ago made for Mike Clark by Magnetics Components in Schiller Park, IL – a company that has been producing transformers since 1943, having been the primary supplier for Valco and various Gibson amps in the ’50s and ’60s. A call to the company revealed that ToneQuest ReportV12. N1. Nov. 20104the transformer Valco sent was essentially their replacement for a Deluxe Reverb, model #40-18002 without bell ends per Clark’s request. We also learned that the company offers a complete range of Classic Tone vintage power and output transformers, including a reverse-engineered clone of a ’55 Triad 5E3 output tranny, model #18022.

We also contacted Paul Patronete at Mercury and requested a ToneClone “brown Deluxe” output transformer, since Larry Cragg had provided them with specific measurements from original OT in Neil’s ’61 tweed Deluxe, confirming that it was indeed a ’61–’62 brown Deluxe tranny. With a total of 6 output transformers to listen to, we took the Deluxe to Jeff Bakos, who set up a rig on his bench that enabled us to clip in each transformer and very quickly switch back and forth between them as we played a guitar through the amp. Are we having fun yet? Here’s what we heard:

Lenco – An excellent authentic “vintage” vibe for those that prefer the classic, if somewhat murkier sound of a tweed amp being pushed, lots of sag in the low end and a jangly pop in the top. And “old,” rather “lo-fi” sound indicative of the ’50s era amps.

Magnetics Components Clark Deluxe 18002 – Similar to the Lenco, but stronger and more robust, with a prominent growling character and voice. Thick, wooly and willin’ with better treble presence and clear string definition then the Lenco, yet an entirely “vintage” character. This tranny is comparable to those found in Deluxe amps from the brown era through silverface. Excellent power, punchy and fat with exceptional clarity and tone.

Magnetic Components 5E3 Clone – Percussive and dynamic with a faster attack response than the Clark/Deluxe Reverb version, this transformer was reverse-engineered from an original ’55 Deluxe OT. IT imparts an intense, throaty tweed character with enhanced mid and treble presence, remarkable clarity, and an authentic vintage ’50s vocal tone with softer bass response and slightly less volume and power than the Deluxe 18002.

Allen/Heyboer TO20 – An interesting variation with a much more modern, percussive dynamic character. The sound was not as heavy and imposing in the vintage style, and with this transformer the Deluxe reminded us of the more refined sound of a Fender Princeton, with excellent dynamic punch for slide and Allen/Heyboer TO26 – As advertised, the low end held up loud and proud with very little sag and an audibly higher threshold of clean headroom, although beyond 6 on the volume control the Deluxe was still holding nothing back. Overall, this transformer imparts a cleaner, high fidelity tone with more clarity and stout bass response than a typical stock 5E3 transformer. An excellent choice for enhanced low-end and maximum volume.

Mercury Magnetics brown Deluxe – Immediately recognizable, the Mercury displayed a trademark sound that is smooth, exceptionally musical, warm and balanced. Sounding more “high fidelity” than the Lemco or Magnetic Components transformers, but still seductively unruly enough to get yer ya-ya’s out. Sweet, rich, detailed and sticky.

Now, you may be wondering why we would bother to audition so many output transformers…. How much difference can it make? Well, forty-odd years ago when someone rigged that old Stancor tranny in the Deluxe, the only choice available to most repair shops was whatever was on hand in the scrap pile. Today we can shape the tone and dynamic response of an amp with a variety of “vintage” or more modern, custom transformers that allow us to recapture the original sound and feel of the amp, or improve upon the original design. Why did Cesar Diaz install output transformers for a Twin Reverb in Stevie’s Super Reverb amps, and Bassman transformers in his Vibroverbs? Because the first thing that chokes and overwhelms a smaller output transformer are the bass frequencies, and Cesar wanted Stevie’s amps to produce a rock-solid, thundering low end that could handle his massive wound strings. The tone we’re celebrating with our ’59 Deluxe is quite the opposite…. The raucous sound of the amp teetering on the edge is the key to it’s exploding tone, but if you wanted to go in the opposite direction with more headroom and a tighter low end, transformers like the TO26 have been specifically designed for that purpose. We once replaced the output transformer in our Pro reverb with a bigger MercuryToneClone Bassman, and the Pro grained a tone of clean headroom and unyielding bottom. Wanna make it even harder still? Use a plug-in diode rectifier in place of the 5AR4 rectifier tube. No saggy britches now. As with so many choices we make in the Quest for tone, the final decision comes down to your mission and individual taste, and Jeff agreed that between the Heyboer TO26, both Magnetic Components trannies and the Mercury brown Deluxe, the question wasn’t which one was “best” – all four were exceptional, but different. Some players would prefer one over another for different reasons described here, but all of them represent stellar examples of just how far we’ve come since the day that old Stancor tranny was used to put the Two Fifty Nine back into service.

One last detail needed to be addressed…. Could we safely run the Deluxe with 5881s or 6L6s if we preferred that sound over 6V6s? Once again, we asked the prescient Mr. Valco for some Hoosier insight:

“The impedance mismatch in this particular amp using the 6L6s is really not a big concern, it won’t hurt the amp and will either sound good or it won’t. The 6L6s draw 1.8 amps and two 6V6s draw 0.9 amp, so using the 6L6s will add about 1 amp more current draw that the power transformer needs to supply from the 6.3 volt heater windings. On some small 6V6 amps, using 6L6s can and does cause the power transformer to run hotter because more current equates to more heat. The concern is that the power transformer in the Deluxe, not being a large one to start with, has the extra 1 amp of heater current capacity to safely use the 6L6s. One way to determine if the power transformer is really stressed out with the 6L6s is to measure the AC heater voltage on pins 2 and 7 on the power tube sockets (or on the pilot lamp) and see if the AC voltage drops significantly from the reading using 6V6s versus 6L6s. It should be a bit over 6.3 volts AC with the 6V6 anyway (since the wall voltage is higher these days than in the early ’60s) and with the 6L6s you sure don’t want to see a large drop in voltage below 6.3 volts AC. If there is a large drop it means the transformer is having trouble supplying enough current for the 6L6 heaters if given enough time with the 6L6s could damage the power transformer. If the drop is only a few 10th of a volt, and doesn’t go below 6.3 AC, then it would indicate that the transformer is supplying the demand for the heater current and should be OK. Most Fender amps used power transformers that could handle some extra current demand.

And now we arrive at the moment of truth. We’ve been steadily reeling in a parade of new and classic amps for review in these pages for 12 years now this month – Marshall, Fender, Magnatone, Hiwatt, Vox, Valco, Silvertone, Ampeg, Gibson, Gretsch, Mesa Boogie, Park, Supro, Dickerson, Traynor, Budda, Western Auto, Standel, Dumble, Cornell, Clark, Crate, Divided by 132, Reeves, Bad Cat, Gabriel, Fuchs, Koch, Star, Category 5, 65 Amps, Balls, Bakos, Callaham, Blankenship, Reinhardt, Grammatico, Siegmund, Chicago Blues Box, Roccaforte, Headstrong, Rivera, Mad Professor, Talos, Maven Peal, Reverend, BC Audio, Savage, Goodsell, Fargen, Carol-Ann, DST, Two Rock, Germino, Matchless, Louis Electric, Swart, Demeter, Juke, Aiken, Bluetron, DeArmond, Carr, Victoria, and Dr. Z, with more coming. Lots of amplifiers, multiple models from the same builders, and among the foremost classics – Fender, Marshall, Vox, Hiwatt, Gibson, Ampeg and the entire Valco catalog, we have acquired, optimized and restored dozens of amps considered to be among the most desirable vintage models ever built. In the 20 watt wheelhouse occupied by the Two Fifty Nine, it has no equal by a mile. Game over.

After a lot of back and forth testing with different sets of output tubes, we became hooked on the thundering sound produced by a pair of Philips small-bottle 6L6WGBs. Thanks to Larry Pogreba’s talent for scavenging rare tubes (in Montana, no less), we are flush with several outstanding and stout pairs of RCA 6L6s, but the brighter Philips really lit up the Deluxe with a fresh and lively attitude that mirrors the bounce of a newer amp. With the ’64 Jensen C12N loaded, the Deluxe spookily nails the tones of Neil Young’s rig on Ragged Glory – a “studio” recording cut live with the Deluxe and Old Black in a barn on Young’s ranch with Crazy Horse. With the volume backed off to 4-5 a bluesy jangle emerges anchored by solid low end, rich midrange, the sweetest treble tones imaginable, and variable levels of sustain and edgy distortion that can be controlled both by the volume on the guitar and pick attack. The Deluxe does not discriminate between single coils or humbuckers, ravaging both with equal fervor, and the responsive dynamic character of this amp simply is not of this world. Rotating the single tone control sharpens treble without dumping lows or mids, while also subtlety increasing gain, as if you were using a boost pedal. A “Y” cord plugged into the Instrument and Microphone inputs enables the two channels to be mixed with great effect. As Neil Young described, bringing the mic input volume up with the instrument volume set between 6-8 gradually deepens the tone while slowly igniting an intense explosion of thicker second order harmonics and distortion as the dynamic character of the amp softens. Pushing the Instrument volume level up into the 8-12 range brings the volume up to a perceived level that exceeds 20 watts, while provoking an angry, pissed-off cascade of astonishingly rich musical distortion as the notes swerve into controlled harmonic feedback.

Switching from the Jensen to the Celestion transforms the Deluxe into the most stunningly toneful 20 watt Marshall you could possibly imagine. To be honest, you probably can’t imagine it, because we have never heard anything like this ourselves, even after owning a couple of vintage Marshall PA20s, a rare Lead & Bass head and 1×12 cabinet, and a Balls 2×12 18 watt. We could easily live with either speaker, and the Deluxe also just kills pushing our 8 ohm 4×12 pinstripe cabinet.

For those of you who appreciate a somewhat tamer vibe, we can assure you that the Deluxe loaded with a fine pair of 6V6s is equally mind-altering. The overall sound is a wee bit smaller in girth and less imposing, yet abundantly overflowing with vivid harmonic depth, a supremely touch-sensitive response, and brilliant combination of fidelity, clarity and bloom. Compared to a black or silverface Deluxe Reverb, the ’59 presents a more musically complex soundstage, less harsh, stiff and linear, and it lacks both the sharper treble of a blackface amp, and the scooped midrange character. The tone is rounder and meatier, the treble sweeter and less dominant, with an enhanced 3-D image.

Now, if you’re the type that skeptically requires a qualifier to add a stamp of legitimacy to such an over-the-top review, here it is, Mr. Been There-Done That…. The Deluxe doesn’t and won’t spew big clean tones at stage volume. Our ’58 Tremolux produces a cleaner tone with a higher threshold of clean headroom by far at comparable volume levels, and the taller tweed cabinet encourages a stronger, cleaner resonant bass and low mid response. The Tremolux is also equipped with a Mercury ToneClone Tremolux output transformer, which creates a tone that is less wooly, raucous and indistinct.

The busted-up sound of the Tremolux above 5–6 is gloriously righteous indeed, but with more clarity and less provocative intensity than the Deluxe. Taken in context, what we’re suggesting here is that in our experience, the Deluxe has no equal as both a Fender and Marshall style 20 watt rocker (depending on speaker selection), and we’ll add “blues” to that description equipped with 6V6s and the Jensen C12N. During our 2-month test period, we also routinely used our Lee Jackson Mr. Springgy reverb, Analogman-modded Boss DD3 digital delay, and a very cool, versatile (and cheap) Flip tube tremolo pedal reviewed here. Can a modern replica of the 5E3 Deluxe deliver the same inspiring tones as the Two Fifty Nine? The closest thing we’ve heard is the Louis Electric “Buster,” but no, magical happy accidents like this Deluxe can’t be reproduced today – and that is as it should and shall always be. Quest forth…

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Of course, the perfect segue would now be to decipher the “special” nature of the original output transformer in Neil Young’s narrow panel tweed Deluxe, providing you with a timeline in which these happy accidents appeared, or better yet, a source for clones of thee special gems via, say, Mercury Magnetics. Sorry… we asked, and while the guys at Mercury had heard the same story about the output transformer in Neil’s Deluxe, we can’t offer any definitive clues to what Larry described as “the most perfect way form.” However, we can immodestly suggest that you snag a TQ Clarksdale [ed. note: built using custom Mercury Magnetics trannys]—a faithful clone of our original 1959 DeArmond 1×12. It’s Neil’s amp in spades and he doesn’t even know it. The first batch of ten have been shipped and a gutsier, louder or more soulful 20 watt 1×12 has never been built. We can’t (and don’t) take credit for the original design—that belongs to an unknown engineer at Rowe Industries in Toledo, Ohio circa 1959—but we can state without any doubt whatsoever that the Clarksdale nails the tone and attitude of the original, and the original is the most impressive 1×12 we have ever heard. It’s got more bottom end and stronger mids than a tweed Deluxe, and where a Deluxe folds up, the Clarksdale roars all the way to “10.” Ain’t no quit in the Clarksdale, and like Neil Young’s Deluxe, a lot of the mojo is found in the DeArmond’s mammoth, original output transformer.

With Young’s legendary tweed Deluxe off the board, we chose to put the vintage Vox AC50 Larry provided for Frank “Pancho” Sampedro on the Ragged Glory tour and recording sessions in play. Now, for those of you who tend to shy away from the potential complications that 40 year-old amps can present, the tale that follows will not inspire confidence, even though in the end, we did reach the promised land.

We found a 1965 gray panel Vox AC50on eBay with a “best offer” option. A search of previously completed auctions revealed that vintage AC50shad recently sold for anywhere from $900 to $1600 (more for the earliest, small box candy panel models with tube rectifiers). Since Larry’s “Pancho Vox” was a mid ’60sgray panel with silicone diode rectifiers, we made an offer of $950 for the ’65, which the seller accepted.So far so good. When the amp arrived from Florida,however, we immediately noticed that the chassis had dropped inside the cabinet. Vintage JMI Vox chassis are mounted on a plywood shelf that allows the amp to slide in and out of the cabinet, and due to the seller’s pathetic packaging job, the plywood board in the AC50had splintered and cracked beneath the weight of the chassis. The shelf was shot, but since a cursory fire-up led us to believe the amp was in good working condition as advertised, we asked for and received a $100 credit and cut a new plywood shelf for the AC50from a reproduction AC30 cabinet we had used to house a vintage ’63 AC30head. Piece of cake, and a very quick and proper fix.

In the interest of authenticity, we also ordered a 4×12 cabinet loaded with aged Celestion G12H30s (Hellatones) from Avatar Speakers. They were running a clearance sale on loaded 4x12s for just $378 and $49 shipping, so we bit, and people, this cabinet kicks the living shit out of our vintage Marshall 4×12.

With the cabinet delivered, we were anxious to uncork the AC50at full roar, and we did—for maybe five minutes. The thick sound of the Vox filled the room, the house and the block with a gorgeous,incendiary bloom through the Avatar cab and our blacktop Les Paul, until the joyous noise was suddenly contaminated with a most noxious and fear-some popping, fizzing and spitting, while we sighted a glowing red spot on the plates in one of the Svetlana EL34s. Not good. Off to Bakos Ampworks….

After an hour of probing on the bench, Jeff asked,“Do you smell that? Man, I think the output transformer is smoked. It’s probably been going out for a while.” Jeff patched in a substitute which eliminated the crackle-spit and confirmed, “It’s toast.” We immediately punched the number for Mercury Magnetics, and with our print deadline looming large, we had the Vox tranny shipped 3-day UPS from California. Jeff popped in the Mercury ToneClone tranny and replaced the original silicon diodes with FREDS. We also A/B’d an older pair of original “Winged C”Svetlana EL34s with a matched pair of NOS TeslaEL34s acquired from KCA NOS Tubes. At $80/pair,the Tesla’s are reportedly comparable to NOS Mullard sat more than three times the price. We also installed two lightly used Mullard ECC83sin the Normal channel and a spare NOS RCA 7025andNOS Teslain the Brilliant channel. But we were still missing an essential ingredient in the “Pancho” rig….

With the Vox AC50 brought back from the brink and the ’57 Junior found, we were finally poised to experi-ence Ragged Glory. We prudently set the volume controls for both channels of the Voxon “7,” following Larry’s recommendations for tone controls—treble dimed and the bass low. We’d ease into “10” on the volume controls later…. With a flick of the toggled tripwire the Vox lit up, and within 10 seconds the P90 was humming through the four Hellatones. We stepped back a few feet, brought the volume control on the Junior all the way up, turned away from the four twelves and cut loose with a tight, slashing chord progression out of E major. Digging deep into the Junior, the Vox responded as the twin EL34s became fully inflamed, gorging on 430 volts. The tone was thick, complex and gloriously ragged with a clarity, punch and trebly character that masked nothing—the perfect burning, churning, flannel and leather rhythm tone. Hit the low E string on a fat E major and it holds…. Come over the top with an upstroke on the E and B strings and the Vox responds with a gorgeous, penetrating cymbal splash that hangs as long as you wish. Need a dash more mids? Dial back the tone poton the Junior, Pow! There it is. Thanks to the FREDS, the entire rig breathes with an extraordinary touch sensitive feel, and even on “7” the Junior could easily be coaxed into howling cries of polyphonic feedback. After 15 minutes, we reached over and dimed both volume controls…. Now we were welding some very serious shit—Mississippi Queen meets Powder finger…. And this was 50 watts of classic, vintage Voxtone, mind you…. Harmonically richer, better endowed and far less linear and one-dimensional than a vintage Marshall—a cross-bred beast with a level of gain, distortion and raw heat far beyond the capabilities of any other vintage British amp unaided by a pedal. The tone, the vibe, the drama of this amp is stunning, and it left us wondering why the vintageAC50 gets so little respect. We can think of no other vintage or current production amps that do what the Vox does. Not one. Of course, your results could vary, so here are a few tips for you brave souls willing to take the plunge.

Don’t be fooled into thinking that the Voxis solely a“rock” amp. Kid Ramos blew us away at a blues gig playing an AC30with a Fender reverb box, and his was one of the best blues tones we’ve ever heard anywhere. Expect the same from an AC30.

Do not fear replaced transformers. You’ll pay less for the amp and the ToneClone replacements from Mercury Magnetics will outperform many tired originals.

Expect the unexpected and coolly deal with it. Voxamps aren’t Fenders—things like speed nuts on the chassis for the cabinet mounting screws are often missing or broken, but they can easily be replaced.Good tubes are also essential, but not every brand will provide reliable performance or the best tone in aVox. You must also exercise extraordinary caution around the AC50when handling the chassis outside the cabinet—even when performing simple tube swaps. The preamp tubes are mounted directly above two uncovered filter caps that remain hot even when the amp is unplugged. One slip and your Quest for Tone could be over.

Plan on investing in a thorough checkup by an experienced amp tech who can deal with cold solder joints, degraded components, old filter caps and proper biasing, before your amp takes a dump. Recommended amp techs follow, along with contact info for Mercury Magnetics.

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In late 2009 I had the opportunity to talk with Sergio Hamernik about the history of the Mercury Magnetics, how he became involved in making transformers for guitar amplifiers, and the difference a high quality transformer can make on your tone.

How did Mercury get its start?

The company’s roots date back to the early ’50s. Mercury was started by an old General Electrics transformer engineer who was working there pre-World War II. He then went on to do a bunch of design work for the war effort. And in the early ’50s, hung a shingle and became self-employed.

The name “Mercury” came out of his passion for Mercury cars, he always drove a Mercury since the late ’40s — he loved those cars — and eventually moved from the East Coast to the West Coast where he found that there was a lot of military and aerospace work. A booming economy in the early ’50s gave him a lot of business.

I met him in the 1970s when I was an engineering student and an audio enthusiast. Back then the electronics world was well into its solid-state “evolution,” and interest in tube gear was quickly disappearing. Not for me, however. I found myself in demand as a guy who knew about those “old things”; not only the math, formulas and specifications but I also had the “ears.” I could fix and keep the old gear running. So, I worked as a hired gun for a bunch of studio heads and pro musicians.

Typically when an amp’s output transformer blew. No one seemed to know any better so it was just swapped by whatever “factory” replacement or an off-the-shelf “equivalent” catalog transformer was handy. The invariable result was that the amp’s characteristic sound was gone. And no matter what resistors, caps or tubes were used, it could not be rescued or returned to its original sound. It was the transformers, it turned out, that were the key. The problem was coming up with a way to remedy the blown transformer replacement or repair that wouldn’t alter its tone.

To further complicate things, most transformer people I dealt with just didn’t want to bother with the music industry. For the most part the established electronics industry considered the needs and opinions of the audio and MI (Music Industry) communities as subjective, run by kooks, and occupied by people who didn’t know what they are doing. Audio and MI had always been considered the illegitimate stepchildren to the rest of the industry.

Out of pure necessity I had to got involved with transformer design and manufacture. As a customer of Mercury, they had built many custom transformers to my specifications — although we had many heated, on-going debates on the subject because the company owner hated audio! He never did understand what made guitar amp transformers tick, or how musicians thought and reacted to them.

That aside, he pestered me for almost a decade to take over the company because he felt I was the only one qualified. Eventually I did, and that was when Mercury got serious about the guitar amp connection. Sometimes you end up becoming an expert at something when no one else wants to do the job.

By the time I took the helm we were developing a really good and workable understanding of the relationship of transformer design to decent tone and how amps should behave. And around 1980 we began the long and arduous task of collecting and cataloging transformer specifications for every vintage amp, from all over the world. The deeper we dug, the more apparent it became that there were all kinds of factors that no one had previously suspected that affected guitar tone. And likewise, no one seemed to be paying attention to such things.

In turn, we invented proprietary technologies to aid this work. Even after three decades, we’re still innovating and discovering new things. From that fundamental research came our now famous ToneClone series, and later the Axiom line, which is probably the most significant advancement in toneful guitar amptransformer designs since the ’50s. Both product lines, we’re proud to say, have distinctly different niches in the annals of guitar amp tone.

We’ve not only cured the old transformer tone issues, but made it possible for musicians to upgrade their existing amps. And we’ve also made it possible for amp builders to reproduce amps of the same or better grade than even the most outstanding vintage amps of the past.

When did you become involved with making transformers for guitar amplifiers?

Back in the ’70s I worked for people on a one-to-one basis, usually under confidential arrangements, with certain rock stars that just didn’t want to be bothered by their names being flaunted around. What they want was their amps running right for recording, projects, touring, etc.

The problem was that when technicians would fix the amps they’d often loose their tone. It turned out that the culprit was the replaced output transformers. A changed output transformer would completely alter the character of the amplifier. So as I was the guy doing most of the work to resolve this issue, this expertise was brought to Mercury where we began a special division to cater to the guitar heroes.

Word got around rather quickly that Mercury was able to repair, rewind, and restore the original transformers and it just grew from there. The whole “Tone Clone” thing came from artists who had these amazing irreplaceable amps, amps that often made recording history. They didn’t want to take these amps on tour. So we came up with the innovative idea of cloning their original transformers that they’d fallen in love with. With the clones we could now easily make, for the first time ever, several identical amps for them. Or they would assign their techs to drop-in the cloned transformers so they would have, for example, six amps that would all sound the same as that first perfect amp.

These artists could now go on tour and not worry about breakdowns or theft, and keep their prized-originals back at home.

I worked with Ken Fisher, the whole Trainwreck thing, and a lot of the early boutique guys — and still do with Alexander Dumble. They preferred to keep things confidential and not let too many people know who their sources were because there were so few transformer designers that catered to the guitar amp market.

There was also a slow-but-steady dumbing-down occurring in audio and all that had been the post World War II momentum. Many of the ex-military components we’d been using were high tolerance parts, with mil-spec formulations of iron and copper and so on, that had been used to win the war effort. During the ’50s and ’60s we enjoyed the benefits of those high quality components at surplus prices. But by the late ’70s, and definitely in the ’80s, steel manufacturers started to change recipes to make the iron and other materials much more affordable.

You can hear the differences between a late ’60s Marshall, a late ’80s Marshall, and a Marshall today. A good listen will really help you to understand what changes took place. Unfortunately they made so many of those changes more out of economic considerations than anything else. The amps were loud but they seemed to be losing sight of the fact that their tone was disappearing — the “recipes” had been changed.

In addition to many other factors, the iron that Mercury uses is custom-formulated specifically for us. We buy enough of it to be able to dictate the exact recipe from the foundries. And all of our iron is literally from American ore processed right here in the USA. 100% American madeto the original specs. Are there drawbacks? Well, some of the iron rusts more easily, but that’s actually a good thing because rust is a natural insulator. But the opposite is also true. When you see a modern transformer with a silvery or a shiny core just know that they aren’t worth a damn when it comes to tone.

Can you tell us more about guitar amp transformer history?

Here’s an amusing anecdote that may help explain our case for guitar amp transformers: There’s a great deal of documentation, from back in the mid-’50s, where engineers, and other technical people, were writing really scathing reports on how awful the transformers were in the audio industry. Those darn transformers! When tubes were plugged into them there was a tendency to distort! And they couldn’t have any of that! Likewise with harmonic distortion — especially even-order harmonic distortion.

Many amp builders, techs and players, today, don’t understand that tubes were originally designed to run dead clean, linear, and be efficient voltage amplifiers. That the tone we’ve all come to know and love is caused by the transformers literally “irritating” the tubes into distortion.

Which is, of course, the whole point of what we are looking for in guitar amps. Back in the ’50s, they were fighting to get rid of those nasty distortion tonal characteristics. Now we embrace them. But that was audio – guitar amps were still in they’re infancy and yet to be realized. It took a generation or two of innovative musicians to take those “undesirable” tonal characteristics and create music; to work with distortion and make it into something musical.

Ironically, it was that no-distortion engineering mindset that ushered in solid-state, and why it was so openly embraced in the ’60s. It was solid-state electronics that eliminated the output transformer.

In the late ’60s, Vox went to Thomas Organ to have solid-state amps built. They were very proud of this state-of-the-art amplifier. Curiously, I met a few of the musicians from the late ’60s that were sponsored by, and using, those amps. The tone was so awful and unbearable that they used the enclosures but hid their old tube gear inside! As you may already be aware, the vacuum tube industry is alive and well, and we’re still waiting for the solid-state industry to catch up.

Part of the confusion is that musicians assume it’s the tubes that give them their tone. There’s a lot of synergy going on in an amp, and the tubes certainly contribute, but let me illustrate this another way. Did you know that there is what we call “output transformer-less” amplifiers in the HiFi world?

These amps basically parallel a bunch of power tubes together until they get down to 16, 8, or 4 ohms. There is no output transformer, so you literally connect the speaker directly to the tubes. If you ever get the opportunity to do an audio demo with this style of amp, you will find that while it works, it sounds nearly solid-state. The output transformer is what provokes a tube into giving the characteristics that we find desirable as far as tone. Audio engineers didn’t want the tubes to distort, as tubes are basically nothing more than very clean voltage amplifiers. But when you have a reactive element like a transformer, you irritate the tubes into harmonic distortion.

Therefore, the difference between a good and mediocre transformer is based on how it works and syncs with these tubes to produce the kind of tone or distortion we are looking for. It is not as easy as winding some wire around a steel core, if it was then we would not be having this conversation.

How does a Mercurytransformer made today compare to the transformers made in the golden age of amps (the ’50s and early ’60s)?

One of the biggest mistakes existing in today’s amplifier community, especially amongst hobbyists and do-it-yourselfers, is to blindly copy every aspect of a vintage amplifier hoping to get a piece of that golden tone. At best, this method still produces very random results. One of the key reasons for this is the often-overlooked missing transformer formula. A builder will fuss around with the tiniest of other details but completely miss how the transformers fit into the equation. In short, get the transformers right, then the rest is much easier. Here’s another look at theses deceptively simple devices:

For vintage-style transformers, Mercury starts by duplicating the transformer design, build errors and all. We use the best grade components like they did in the ’50s and ’60s. We wind every layer and every turn as if it were a circuit in itself. In fact, the diagram on the left shows an output transformer circuit equivalent. Most people would think it is an audio circuit. These things are fairly complex, and all the numbers have to be right in order to get the tone we want as musicians.

We really do follow the recipe to a point. Although we don’t repeat any of the mistakes or inconsistencies that were prevalent, but didn’t affect tone. For example, if you were into Fender tweeds or late-’60s Marshalls. To do this we would literally put the word out to rent or borrow dozens of amplifiers to find the one or two that had thesound, and dismiss the rest. There were typically many inconsistencies as well as “happy accidents” in the best-sounding examples we’ve auditioned. A lot of this has to do with the sloppy tolerances of the original transformers.

For our transformers we extract the best parts and virtues of the original best-of-breed transformers and remove all of the obstacles to tone. Perhaps just as important is that we adopted a “cost is no object” approach, making our transformers equal or better than the originals — and then add consistency. We now have this so finely tuned that if you bought a transformer from us five years ago, and then the same one today, it would sound exactly the same. You don’t want good batches and bad batches, which is precisely what made the original production runs vary so much.

Another issue is the so-called controversy between paper tubes and nylon bobbins. In the vintage years they used both. Some people think that somehow, some magical quality comes from using a paper tube winding form over a nylon bobbin. Tonally it made no difference at all. Paper tubes were widely out of tolerance most of the time because of how they were made. They would wind multiple coils on long sticks then use a saw or blade to cut off the various coils. In order for these long tubes or coils to come off of their winding forms they had to be conical. So this invariably meant that the first coil would be larger in diameter and the last coils smaller. As you can see, it’s easy to see why each of these inconsistently-made bobbins had a greater difference than the material they were made from. And there are other issues that occur over time, like paper has a tendency to disintegrate, collect moisture, etc.

When we switched to using nylon bobbins the tolerances were within 3,000’s of an inch of each other, as opposed to the wildly varying amounts found in paper tubes. If you were ever to take apart a really old transformer (pre-’70s) sometimes you’ll find wood wedges that are jammed between the paper tube and the core because that piece of paper was too wide and too sloppy to fit into the core correctly! They would force a wedge in there so the darn things wouldn’t rattle!

Which method, paper or nylon, made for the best tone? It’s the luck of the draw. We’re fortunate in that we have all these stars as clients who have these amazing-sounding amps. They went through the hassle of culling and choosing and picking the special amps that inspired them. The amps they recorded with. When we analyzed their transformers we sometimes found happy accidents or other little anomalies that would set a transformer apart from already sloppy tolerances of the standard production run.

There are little subtleties and changes from one transformer to another that make a heck of a difference tonally. So when you look online at our list of ToneClones, just know that they are from the hand-picked, best-of-the-best amps of their model and era. We continue this “weeding” process every day — and there’s apparently no end in sight. And that’s why, with some amps, we have several versions — each with its own tonal qualities — and others only a single set to choose from.

We use this process to establish new benchmarks. And you never know, tomorrow a new variant may arrive that totally blows away what we already thought was as good as it could ever get.

It is interesting that you take that approach to upgrading — the never-ending search for better-sounding benchmarks.

There is no real money or glamour in what we do, it is really all born of a passion for music. I come from a musical family, my Mom taught me as a little kid that music was a form of “food.” And that hasn’t changed. Everyone who works at Mercury is just in love with playing and listening to music, and we all believe that there is always some room for improvement or a way to raise the bar somehow.

Back in the ’70s and ’80s there wasn’t really a need for a company that designed and sold transformers to the public, so I stayed away from the general public for as long as I could and really only worked with professionals.

But at some point I realized that it was the average player who was getting ripped-off. Things were getting dumbed-down, the tone is slowly and steadily being vacuumed out of the amps. They were becoming duller-sounding, less interesting and more noisy. So, we decided to formally launch this product line so the average guy could have access to our technology. It takes an extreme amount of labor and effort it takes to build them to this standard. You know, even if someone wanted to buy 1000 transformers we would have to no-bid them because we really don’t have any way of doing things quickly.

Automation isn’t a practical solution. Everything we do is wound by hand, one at a time; it is the only way it can be done. Say you have 100 turns and 10 layers, well that would mean 10 turns per layer — that is how a machine would think of it. But what if a rock legend’s best transformer was 9 turns on one layer, 11 turns on the next, 7 on the next, 3 after that and so on, but the sum total ended up being 100 turns. Sometimes one layer can have a different winding style than the other; sometimes it is non-symmetrical meaning, if it is a push-pull, that one side of the primary doesn’t have the same turns as the other side. If that was the recipe that created the magic, we’d have to duplicate it. It’s just not practical to build machines to do that, so we end up having to do it by hand. It’s the proud old-school craftsmanship way of doing things. Something I think we could see a lot more these days.

We have a reputation for nailing tone. Our Fender transformers don’t sound like Marshalls, they sound like Fenders — and vice versa. In fact, we’ve become the industry’s new standard. If you were going to design or create a tube-based amp, it’s clear that we’re the folks to talk to.

Can you explain how a Mercurytransformer can improve an amplifier’s tone and how they outperform the stock transformers found in most amplifiers?

In designing toneful transformers specifically for guitars (and that’s all we’re talking about here, not necessarily transformers for HiFi or any other purpose), the trick is in the magnetic field and how it behaves. The nature and the speed with which the iron reacts to the changing of an alternating current, in an alternating magnetic field, is what makes tone happen.

If you have “slow” iron, you’ll have a dull, non-sparkly sound with no bell tones — no matter what you do with the amp it will always be kind of noisy and fuzzy.

Where others have tried and failed they’ve blindly followed generic transformer formulas without understanding that guitar amps are different animals. They’ve somehow missed that point despite all the evidence to the contrary. The fact is that transformers for guitar amps do not necessarily follow textbook rules.

Indeed, it should probably be noted that we’ve developed a whole new technology around transformer design specifically, and only for the guitar industry. And that these designs are essentially irrelevant to any other use. But Mercury is also in a highly unusual position. Our decades of transformer “vivisection” have revealed all manner of unconventional tips ‘n tricks to us. And we’re now the keepers of this new, but proprietary, technology.

I seriously doubt that we could have done it without the, let’s call it “archeological benefits,” of our observations. Decades of studying the good, the bad and the ugly of guitar amp transformers have revealed a great deal.

Nothing that I have found in the reissue market, transformer-wise, even resembles anything that was made during the “the golden age of tone.” They are unrelated. The inductance, magnetic fields — all of that is just completely different and far removed from the original designs and recipes. So there is no way that a reissue amp is ever going to sound vintage unless they bother putting in the right ingredients.

With our Upgrade Kits, for example we’re trying to show people that we can move forward into new sonic territory from where vintage designs and tone left off. And our Axiom series transformers are the definitive showcase for this technology. Their tone is just amazing.

To push the point even further, we don’t include any “voodoo” parts in our Upgrade Kits. With the exception of the transformers, the Kits use only common, everyday, and off-the-shelf components. And most of our Kits also include a Mini-Choke. When the circuitry is correctly designed a Mini-Choke will make a huge improvement in an amp’s tone because, in terms of its power supply, it changes the way the amp works.

A good guitar amp is only as good as its power supply. If you have a dynamic and moving power supply that reacts to the demands of the audio end you’ll get get great note separation and good bass dynamics. You start to hear chimes and other phenomenon, and even the harmonics between the strings like a “5th note.” What the heck is the “5th note”? In barbershop quartets, if they get their harmonies right, they hear the “5th note” which is basically a harmonic of all four singers. We are doing that with our guitars thanks to distorted amplifiers.

Where did the idea for offering an Upgrade Kit for amplifiers like the Champ “600” and Valve Jr. come from and who designed the Upgrade?

I designed all of the magnetics (the transformersandMini-Choke) and the general concept behind the Upgrade in league with Allen Cyr from the Amp Exchange. He is one of the most competent, finest amp designers I know of; there are only about five in the world that are true masters of the art — those who really know the math, how to read tone, how to listen to the subtleties of clean and overdriven sounds and tones, design circuits, and understand tube behaviors. As a bonus to those who appreciate this kind of thing, we always try to throw in some interesting tweaks and tricks that are unorthodox.

The idea is to spark some interest and perhaps get more people involved in tube-based amp tone and evolution. We expect some folks to study our Upgrade Kits, learn from what we’ve done, and take off into new territory from there. No one is offended by that.

But our initial concept was to take an inexpensive stock amplifier, one that cost no more than $100 or so, and modify it into a professional- or recording-quality amp for very few bucks. The Valve Jr. was the amp that gave us the inspiration for this project. Epiphone broke the mold with their little Valve Jr. amp. Out of the box it’s a remarkable value. So, although it was a bit of a challenge I thought it was interesting because we were not stepping on anyone’s toes — we were just taking something that already existed and designing an Upgrade Kit around it. A simple proof of concept that made the case of transformers and guitar tone. It just seemed like a cool thing to do. The project was validated when pro players began demo’ing our prototype amps — they couldn’t believe how amazingly great such a tiny amp could sound, it freaked them out, and they all wanted one of their own!

Our intention was to give the kid who was practicing guitar in his bedroom, whose parents are on a limited budget, REAL guitar tone. In a typical scenario, the parents buy a cheap little amp and guitar combo because they want to see if their kid will stick with it. But the kid doesn’t understand that the sound of the amp is fatiguing. He doesn’t understand why the amp doesn’t sound good. And he doesn’t realize that the amp is fighting him, tiring him out. I know that happened to me and so many of my friends when we were kids. Struggling with hard-to-play guitars and poor-sounding amps is probably the single-most reason so many budding young (and old) guitarists give up the pursuit of their dream. But some are rescued. One day they visit a guy, or hear someone play, who has the amp with the tone and with just the sweep a few chords they experience the “My gawd!!! I want to sound like this!” phenomenon.

That is what we’re trying to offer with these Upgrade Kits — where thetone is accessible to just about anyone. So they could have an amp that wasn’t dull or desensitized. An amp that allows them to make that real connection to the tone. Tone is not just about noise and volume, it is rather complex, and undeniably emotional.

At the LA Amp Show we had our Upgraded Fender Champion “600” running into a full Marshall stack. Here we had this little amp powering eight 12″ speakers and it sounded great. People kept asking to see the back of the amp thinking that we had somehow rigged up something, but it was just the little Champ “600” with our Upgrade Kit.

When you have a nice open tone it is not about counting watts because the window is so big and wide and the soundstage is so deep that it gives you the impression of more power. We are not putting out more power with the Upgraded “600” — but it sure sounds like it! It’s about opening up that tone window and giving you more.

It’s kind of like taking a radio whose volume is set to half way and having it placed about 20 feet away from you then bring it right next to your ear — the volume has not changed but you hear a lot more of its content.

One of the things we do when modifying a circuit is to lower the noise floor, which a lot of people overlook. Many amps, like the Valve Jr., have a nasty hum in standby. We had one that would just start to howl if you left it alone for a while! So whatever high noise floor it had would eventually feedback on itself and cause that noise.

Our focus is on inspiring people. We are trying to show people that they really can get great tone today, that there is no age that has come and gone. There is still a lot of fun things left to do with your amplifier when you are on the search for great tone.

Hearing how much these Kits improve upon the tone of the amplifiers, and how well thought-out they are, will a Mercury amplifier that is designed and built by you ever make an appearance?

No. We are a supplier of key components to the boutique industry and to several of the large amplifier companies, and that is a comfortable spot to be in.

There is no shortage of amplifier companies out there and it really is a conflict of interest if we were to start selling amps and transformers. I would rather stay out of it.

The whole point of the Upgrade Kits was an area where I didn’t see any conflict with the people who were in the amplifier business. In the end the Kits really represent a transformer demonstration. If you were to just show someone a picture of a transformer or even had one in your hand and tried to explain how much better their tone would be, no one would care — it’s a yawner. But when you build one of these inexpensive Upgrade Kits and you actually hear the difference that the transformers make, it really drives home our point that transformers are important, that they are the building blocks of guitar amp tone.

And in the end we do this because we love it, we really love what we do. We get to create all of these products that help people find their tone, and who wouldn’t what to do that?

Source: https://mercurymagnetics.com/pages/news/GuitarFixation/SHinterview/index.htm

In late 2009 I had the opportunity to talk with Sergio Hamernik about the history of the Mercury Magnetics, how he became involved in making transformers for guitar amplifiers, and the difference a high quality transformer can make on your tone.

How did Mercury get its start?

The company’s roots date back to the early ’50s. Mercury was started by an old General Electrics transformer engineer who was working there pre-World War II. He then went on to do a bunch of design work for the war effort. And in the early ’50s, hung a shingle and became self-employed.

The name “Mercury” came out of his passion for Mercury cars, he always drove a Mercury since the late ’40s — he loved those cars — and eventually moved from the East Coast to the West Coast where he found that there was a lot of military and aerospace work. A booming economy in the early ’50s gave him a lot of business.

I met him in the 1970s when I was an engineering student and an audio enthusiast. Back then the electronics world was well into its solid-state “evolution,” and interest in tube gear was quickly disappearing. Not for me, however. I found myself in demand as a guy who knew about those “old things”; not only the math, formulas and specifications but I also had the “ears.” I could fix and keep the old gear running. So, I worked as a hired gun for a bunch of studio heads and pro musicians.

Typically when an amp’s output transformer blew. No one seemed to know any better so it was just swapped by whatever “factory” replacement or an off-the-shelf “equivalent” catalog transformer was handy. The invariable result was that the amp’s characteristic sound was gone. And no matter what resistors, caps or tubes were used, it could not be rescued or returned to its original sound. It was the transformers, it turned out, that were the key. The problem was coming up with a way to remedy the blown transformer replacement or repair that wouldn’t alter its tone.

To further complicate things, most transformer people I dealt with just didn’t want to bother with the music industry. For the most part the established electronics industry considered the needs and opinions of the audio and MI (Music Industry) communities as subjective, run by kooks, and occupied by people who didn’t know what they are doing. Audio and MI had always been considered the illegitimate stepchildren to the rest of the industry.

Out of pure necessity I had to got involved with transformer design and manufacture. As a customer of Mercury, they had built many custom transformers to my specifications — although we had many heated, on-going debates on the subject because the company owner hated audio! He never did understand what made guitar amp transformers tick, or how musicians thought and reacted to them.

That aside, he pestered me for almost a decade to take over the company because he felt I was the only one qualified. Eventually I did, and that was when Mercury got serious about the guitar amp connection. Sometimes you end up becoming an expert at something when no one else wants to do the job.

By the time I took the helm we were developing a really good and workable understanding of the relationship of transformer design to decent tone and how amps should behave. And around 1980 we began the long and arduous task of collecting and cataloging transformer specifications for every vintage amp, from all over the world. The deeper we dug, the more apparent it became that there were all kinds of factors that no one had previously suspected that affected guitar tone. And likewise, no one seemed to be paying attention to such things.

In turn, we invented proprietary technologies to aid this work. Even after three decades, we’re still innovating and discovering new things. From that fundamental research came our now famous ToneClone series, and later the Axiom line, which is probably the most significant advancement in toneful guitar amp transformer designs since the ’50s. Both product lines, we’re proud to say, have distinctly different niches in the annals of guitar amp tone.

We’ve not only cured the old transformer tone issues, but made it possible for musicians to upgrade their existing amps. And we’ve also made it possible for amp builders to reproduce amps of the same or better grade than even the most outstanding vintage amps of the past.

When did you become involved with making transformers for guitar amplifiers?

Back in the ’70s I worked for people on a one-to-one basis, usually under confidential arrangements, with certain rock stars that just didn’t want to be bothered by their names being flaunted around. What they want was their amps running right for recording, projects, touring, etc.

The problem was that when technicians would fix the amps they’d often loose their tone. It turned out that the culprit was the replaced output transformers. A changed output transformer would completely alter the character of the amplifier. So as I was the guy doing most of the work to resolve this issue, this expertise was brought to Mercury where we began a special division to cater to the guitar heroes.

Word got around rather quickly that Mercury was able to repair, rewind, and restore the original transformers and it just grew from there. The whole “Tone Clone” thing came from artists who had these amazing irreplaceable amps, amps that often made recording history. They didn’t want to take these amps on tour. So we came up with the innovative idea of cloning their original transformers that they’d fallen in love with. With the clones we could now easily make, for the first time ever, several identical amps for them. Or they would assign their techs to drop-in the cloned transformers so they would have, for example, six amps that would all sound the same as that first perfect amp.

These artists could now go on tour and not worry about breakdowns or theft, and keep their prized-originals back at home.

I worked with Ken Fisher, the whole Trainwreck thing, and a lot of the early boutique guys — and still do with Alexander Dumble. They preferred to keep things confidential and not let too many people know who their sources were because there were so few transformer designers that catered to the guitar amp market.

There was also a slow-but-steady dumbing-down occurring in audio and all that had been the post World War II momentum. Many of the ex-military components we’d been using were high tolerance parts, with mil-spec formulations of iron and copper and so on, that had been used to win the war effort. During the ’50s and ’60s we enjoyed the benefits of those high quality components at surplus prices. But by the late ’70s, and definitely in the ’80s, steel manufacturers started to change recipes to make the iron and other materials much more affordable.

You can hear the differences between a late ’60s Marshall, a late ’80s Marshall, and a Marshall today. A good listen will really help you to understand what changes took place. Unfortunately they made so many of those changes more out of economic considerations than anything else. The amps were loud but they seemed to be losing sight of the fact that their tone was disappearing — the “recipes” had been changed.

In addition to many other factors, the iron that Mercury uses is custom-formulated specifically for us. We buy enough of it to be able to dictate the exact recipe from the foundries. And all of our iron is literally from American ore processed right here in the USA. 100% American made to the original specs. Are there drawbacks? Well, some of the iron rusts more easily, but that’s actually a good thing because rust is a natural insulator. But the opposite is also true. When you see a modern transformer with a silvery or a shiny core just know that they aren’t worth a damn when it comes to tone.

Can you tell us more about guitar amp transformer history?

Here’s an amusing anecdote that may help explain our case for guitar amp transformers: There’s a great deal of documentation, from back in the mid-’50s, where engineers, and other technical people, were writing really scathing reports on how awful the transformers were in the audio industry. Those darn transformers! When tubes were plugged into them there was a tendency to distort! And they couldn’t have any of that! Likewise with harmonic distortion — especially even-order harmonic distortion.

Many amp builders, techs and players, today, don’t understand that tubes were originally designed to run dead clean, linear, and be efficient voltage amplifiers. That the tone we’ve all come to know and love is caused by the transformers literally “irritating” the tubes into distortion.

Which is, of course, the whole point of what we are looking for in guitar amps. Back in the ’50s, they were fighting to get rid of those nasty distortion tonal characteristics. Now we embrace them. But that was audio – guitar amps were still in they’re infancy and yet to be realized. It took a generation or two of innovative musicians to take those “undesirable” tonal characteristics and create music; to work with distortion and make it into something musical.

Ironically, it was that no-distortion engineering mindset that ushered in solid-state, and why it was so openly embraced in the ’60s. It was solid-state electronics that eliminated the output transformer.

In the late ’60s, Vox went to Thomas Organ to have solid-state amps built. They were very proud of this state-of-the-art amplifier. Curiously, I met a few of the musicians from the late ’60s that were sponsored by, and using, those amps. The tone was so awful and unbearable that they used the enclosures but hid their old tube gear inside! As you may already be aware, the vacuum tube industry is alive and well, and we’re still waiting for the solid-state industry to catch up.

Part of the confusion is that musicians assume it’s the tubes that give them their tone. There’s a lot of synergy going on in an amp, and the tubes certainly contribute, but let me illustrate this another way. Did you know that there is what we call “output transformer-less” amplifiers in the HiFi world?

These amps basically parallel a bunch of power tubes together until they get down to 16, 8, or 4 ohms. There is no output transformer, so you literally connect the speaker directly to the tubes. If you ever get the opportunity to do an audio demo with this style of amp, you will find that while it works, it sounds nearly solid-state. The output transformer is what provokes a tube into giving the characteristics that we find desirable as far as tone. Audio engineers didn’t want the tubes to distort, as tubes are basically nothing more than very clean voltage amplifiers. But when you have a reactive element like a transformer, you irritate the tubes into harmonic distortion.

Therefore, the difference between a good and mediocre transformer is based on how it works and syncs with these tubes to produce the kind of tone or distortion we are looking for. It is not as easy as winding some wire around a steel core, if it was then we would not be having this conversation.

How does a Mercury transformer made today compare to the transformers made in the golden age of amps (the ’50s and early ’60s)?

One of the biggest mistakes existing in today’s amplifier community, especially amongst hobbyists and do-it-yourselfers, is to blindly copy every aspect of a vintage amplifier hoping to get a piece of that golden tone. At best, this method still produces very random results. One of the key reasons for this is the often-overlooked missing transformer formula. A builder will fuss around with the tiniest of other details but completely miss how the transformers fit into the equation. In short, get the transformers right, then the rest is much easier. Here’s another look at theses deceptively simple devices:

For vintage-style transformers, Mercury starts by duplicating the transformer design, build errors and all. We use the best grade components like they did in the ’50s and ’60s. We wind every layer and every turn as if it were a circuit in itself. In fact, the diagram on the left shows an output transformer circuit equivalent. Most people would think it is an audio circuit. These things are fairly complex, and all the numbers have to be right in order to get the tone we want as musicians.

We really do follow the recipe to a point. Although we don’t repeat any of the mistakes or inconsistencies that were prevalent, but didn’t affect tone. For example, if you were into Fender tweeds or late-’60s Marshalls. To do this we would literally put the word out to rent or borrow dozens of amplifiers to find the one or two that had the sound, and dismiss the rest. There were typically many inconsistencies as well as “happy accidents” in the best-sounding examples we’ve auditioned. A lot of this has to do with the sloppy tolerances of the original transformers.

For our transformers we extract the best parts and virtues of the original best-of-breed transformers and remove all of the obstacles to tone. Perhaps just as important is that we adopted a “cost is no object” approach, making our transformers equal or better than the originals — and then add consistency. We now have this so finely tuned that if you bought a transformer from us five years ago, and then the same one today, it would sound exactly the same. You don’t want good batches and bad batches, which is precisely what made the original production runs vary so much.

Another issue is the so-called controversy between paper tubes and nylon bobbins. In the vintage years they used both. Some people think that somehow, some magical quality comes from using a paper tube winding form over a nylon bobbin. Tonally it made no difference at all. Paper tubes were widely out of tolerance most of the time because of how they were made. They would wind multiple coils on long sticks then use a saw or blade to cut off the various coils. In order for these long tubes or coils to come off of their winding forms they had to be conical. So this invariably meant that the first coil would be larger in diameter and the last coils smaller. As you can see, it’s easy to see why each of these inconsistently-made bobbins had a greater difference than the material they were made from. And there are other issues that occur over time, like paper has a tendency to disintegrate, collect moisture, etc.

When we switched to using nylon bobbins the tolerances were within 3,000’s of an inch of each other, as opposed to the wildly varying amounts found in paper tubes. If you were ever to take apart a really old transformer (pre-’70s) sometimes you’ll find wood wedges that are jammed between the paper tube and the core because that piece of paper was too wide and too sloppy to fit into the core correctly! They would force a wedge in there so the darn things wouldn’t rattle!

Which method, paper or nylon, made for the best tone? It’s the luck of the draw. We’re fortunate in that we have all these stars as clients who have these amazing-sounding amps. They went through the hassle of culling and choosing and picking the special amps that inspired them. The amps they recorded with. When we analyzed their transformers we sometimes found happy accidents or other little anomalies that would set a transformer apart from already sloppy tolerances of the standard production run.

There are little subtleties and changes from one transformer to another that make a heck of a difference tonally. So when you look online at our list of ToneClones, just know that they are from the hand-picked, best-of-the-best amps of their model and era. We continue this “weeding” process every day — and there’s apparently no end in sight. And that’s why, with some amps, we have several versions — each with its own tonal qualities — and others only a single set to choose from.

We use this process to establish new benchmarks. And you never know, tomorrow a new variant may arrive that totally blows away what we already thought was as good as it could ever get.

It is interesting that you take that approach to upgrading — the never-ending search for better-sounding benchmarks.

There is no real money or glamour in what we do, it is really all born of a passion for music. I come from a musical family, my Mom taught me as a little kid that music was a form of “food.” And that hasn’t changed. Everyone who works at Mercury is just in love with playing and listening to music, and we all believe that there is always some room for improvement or a way to raise the bar somehow.

Back in the ’70s and ’80s there wasn’t really a need for a company that designed and sold transformers to the public, so I stayed away from the general public for as long as I could and really only worked with professionals.

But at some point I realized that it was the average player who was getting ripped-off. Things were getting dumbed-down, the tone is slowly and steadily being vacuumed out of the amps. They were becoming duller-sounding, less interesting and more noisy. So, we decided to formally launch this product line so the average guy could have access to our technology. It takes an extreme amount of labor and effort it takes to build them to this standard. You know, even if someone wanted to buy 1000 transformers we would have to no-bid them because we really don’t have any way of doing things quickly.

Automation isn’t a practical solution. Everything we do is wound by hand, one at a time; it is the only way it can be done. Say you have 100 turns and 10 layers, well that would mean 10 turns per layer — that is how a machine would think of it. But what if a rock legend’s best transformer was 9 turns on one layer, 11 turns on the next, 7 on the next, 3 after that and so on, but the sum total ended up being 100 turns. Sometimes one layer can have a different winding style than the other; sometimes it is non-symmetrical meaning, if it is a push-pull, that one side of the primary doesn’t have the same turns as the other side. If that was the recipe that created the magic, we’d have to duplicate it. It’s just not practical to build machines to do that, so we end up having to do it by hand. It’s the proud old-school craftsmanship way of doing things. Something I think we could see a lot more these days.

We have a reputation for nailing tone. Our Fender transformers don’t sound like Marshalls, they sound like Fenders — and vice versa. In fact, we’ve become the industry’s new standard. If you were going to design or create a tube-based amp, it’s clear that we’re the folks to talk to.

Can you explain how a Mercury transformer can improve an amplifier’s tone and how they outperform the stock transformers found in most amplifiers?

In designing toneful transformers specifically for guitars (and that’s all we’re talking about here, not necessarily transformers for HiFi or any other purpose), the trick is in the magnetic field and how it behaves. The nature and the speed with which the iron reacts to the changing of an alternating current, in an alternating magnetic field, is what makes tone happen.

If you have “slow” iron, you’ll have a dull, non-sparkly sound with no bell tones — no matter what you do with the amp it will always be kind of noisy and fuzzy.

Where others have tried and failed they’ve blindly followed generic transformer formulas without understanding that guitar amps are different animals. They’ve somehow missed that point despite all the evidence to the contrary. The fact is that transformers for guitar amps do not necessarily follow textbook rules.

Indeed, it should probably be noted that we’ve developed a whole new technology around transformer design specifically, and only for the guitar industry. And that these designs are essentially irrelevant to any other use. But Mercury is also in a highly unusual position. Our decades of transformer “vivisection” have revealed all manner of unconventional tips ‘n tricks to us. And we’re now the keepers of this new, but proprietary, technology.

I seriously doubt that we could have done it without the, let’s call it “archeological benefits,” of our observations. Decades of studying the good, the bad and the ugly of guitar amp transformers have revealed a great deal.

Nothing that I have found in the reissue market, transformer-wise, even resembles anything that was made during the “the golden age of tone.” They are unrelated. The inductance, magnetic fields — all of that is just completely different and far removed from the original designs and recipes. So there is no way that a reissue amp is ever going to sound vintage unless they bother putting in the right ingredients.

With our Upgrade Kits, for example we’re trying to show people that we can move forward into new sonic territory from where vintage designs and tone left off. And our Axiom series transformers are the definitive showcase for this technology. Their tone is just amazing.

To push the point even further, we don’t include any “voodoo” parts in our Upgrade Kits. With the exception of the transformers, the Kits use only common, everyday, and off-the-shelf components. And most of our Kits also include a Mini-Choke. When the circuitry is correctly designed a Mini-Choke will make a huge improvement in an amp’s tone because, in terms of its power supply, it changes the way the amp works.

A good guitar amp is only as good as its power supply. If you have a dynamic and moving power supply that reacts to the demands of the audio end you’ll get get great note separation and good bass dynamics. You start to hear chimes and other phenomenon, and even the harmonics between the strings like a “5th note.” What the heck is the “5th note”? In barbershop quartets, if they get their harmonies right, they hear the “5th note” which is basically a harmonic of all four singers. We are doing that with our guitars thanks to distorted amplifiers.

Where did the idea for offering an Upgrade Kit for amplifiers like the Champ “600” and Valve Jr. come from and who designed the Upgrade?

I designed all of the magnetics (the transformers and Mini-Choke) and the general concept behind the Upgrade in league with Allen Cyr from the Amp Exchange. He is one of the most competent, finest amp designers I know of; there are only about five in the world that are true masters of the art — those who really know the math, how to read tone, how to listen to the subtleties of clean and overdriven sounds and tones, design circuits, and understand tube behaviors. As a bonus to those who appreciate this kind of thing, we always try to throw in some interesting tweaks and tricks that are unorthodox.

The idea is to spark some interest and perhaps get more people involved in tube-based amp tone and evolution. We expect some folks to study our Upgrade Kits, learn from what we’ve done, and take off into new territory from there. No one is offended by that.

But our initial concept was to take an inexpensive stock amplifier, one that cost no more than $100 or so, and modify it into a professional- or recording-quality amp for very few bucks. The Valve Jr. was the amp that gave us the inspiration for this project. Epiphone broke the mold with their little Valve Jr. amp. Out of the box it’s a remarkable value. So, although it was a bit of a challenge I thought it was interesting because we were not stepping on anyone’s toes — we were just taking something that already existed and designing an Upgrade Kit around it. A simple proof of concept that made the case of transformers and guitar tone. It just seemed like a cool thing to do. The project was validated when pro players began demo’ing our prototype amps — they couldn’t believe how amazingly great such a tiny amp could sound, it freaked them out, and they all wanted one of their own!

Our intention was to give the kid who was practicing guitar in his bedroom, whose parents are on a limited budget, REAL guitar tone. In a typical scenario, the parents buy a cheap little amp and guitar combo because they want to see if their kid will stick with it. But the kid doesn’t understand that the sound of the amp is fatiguing. He doesn’t understand why the amp doesn’t sound good. And he doesn’t realize that the amp is fighting him, tiring him out. I know that happened to me and so many of my friends when we were kids. Struggling with hard-to-play guitars and poor-sounding amps is probably the single-most reason so many budding young (and old) guitarists give up the pursuit of their dream. But some are rescued. One day they visit a guy, or hear someone play, who has the amp with the tone and with just the sweep a few chords they experience the “My gawd!!! I want to sound like this!” phenomenon.

That is what we’re trying to offer with these Upgrade Kits — where the tone is accessible to just about anyone. So they could have an amp that wasn’t dull or desensitized. An amp that allows them to make that real connection to the tone. Tone is not just about noise and volume, it is rather complex, and undeniably emotional.

At the LA Amp Show we had our Upgraded Fender Champion “600” running into a full Marshall stack. Here we had this little amp powering eight 12″ speakers and it sounded great. People kept asking to see the back of the amp thinking that we had somehow rigged up something, but it was just the little Champ “600” with our Upgrade Kit.

When you have a nice open tone it is not about counting watts because the window is so big and wide and the soundstage is so deep that it gives you the impression of more power. We are not putting out more power with the Upgraded “600” — but it sure sounds like it! It’s about opening up that tone window and giving you more.

It’s kind of like taking a radio whose volume is set to half way and having it placed about 20 feet away from you then bring it right next to your ear — the volume has not changed but you hear a lot more of its content.

One of the things we do when modifying a circuit is to lower the noise floor, which a lot of people overlook. Many amps, like the Valve Jr., have a nasty hum in standby. We had one that would just start to howl if you left it alone for a while! So whatever high noise floor it had would eventually feedback on itself and cause that noise.

Our focus is on inspiring people. We are trying to show people that they really can get great tone today, that there is no age that has come and gone. There is still a lot of fun things left to do with your amplifier when you are on the search for great tone.

Hearing how much these Kits improve upon the tone of the amplifiers, and how well thought-out they are, will a Mercury amplifier that is designed and built by you ever make an appearance?

No. We are a supplier of key components to the boutique industry and to several of the large amplifier companies, and that is a comfortable spot to be in.

There is no shortage of amplifier companies out there and it really is a conflict of interest if we were to start selling amps and transformers. I would rather stay out of it.

The whole point of the Upgrade Kits was an area where I didn’t see any conflict with the people who were in the amplifier business. In the end the Kits really represent a transformer demonstration. If you were to just show someone a picture of a transformer or even had one in your hand and tried to explain how much better their tone would be, no one would care — it’s a yawner. But when you build one of these inexpensive Upgrade Kits and you actually hear the difference that the transformers make, it really drives home our point that transformers are important, that they are the building blocks of guitar amp tone.

And in the end we do this because we love it, we really love what we do. We get to create all of these products that help people find their tone, and who wouldn’t what to do that?

Last month, we dropped off a toasted output transformer from a 1950 Vox AC15 with Sergio Hamernik and the team at Mercury Magnetics. From a suspicious pin-sized burn in the transformer’s outer paper insulation, they were able to determin probable causes for the transformers untimely demise. Then it was onto the rewind process! So, is it over for this amp’s output transformer?

VG: What goes into the process of rewinding a transformer?

We begin the restoration process with a thorough testing of the transformer’s electrical performance. Then we put the transformer’s insulation system through its paces – checking its integrity, making sure the voltages inside the transformer stay where they belong and not going wonky by arcing over to neighboring windings.

Consider these steps a weeding out process to find the proper candidates for restoration. If the transformer in question passes, then we return the transformer back to its owner or tech. Believe it or not, about 1-in-4 transformers we receive pass our testing! We offer free-of-charge transformer testing to anyone – all they have to do is cover the shipping costs. Some of these transformers are sent to us simply to make sure that all is operating well within specs – essentially for a second opinion.

We consider it a “sin,” a violation of our sense of professional ethics, to tamper with a perfectly good transformer. Rewinding or restoring transformers is a service born out of our passion for preserving tone at its highest standards. Properly rewinding transformers is a time-consuming and costly endeavor. The reality is that our rewinding service is not exactly a profit center. Who knows, maybe one day we’ll sober up and quit doing it altogether. But it does break our hearts when we find vintage transformers ruined by feeble attempts at rewinding by people who do not posses the necessary skills, or who do not have an interest in or knowledge of guitar tone.

If the transformer does fail our testing in any way, then we deem it unsafe to be put back in its amp. Now the process of rewinding begins. A large part of this process is akin to archaeology, or perhaps autopsy. We want to find out precisely how it was made and discover who or what killed it. So the first thing we do is remove the core stack and catalog each plate for original position and sequence. Check out the photo of your core completely apart and tagged. We did find some rust and will do our best to preserve it.

it. So the first thing we do is remove the core stack and catalog each plate for original position and sequence. Check out the photo of your core completely apart and tagged. We did find some rust and will do our best to preserve it.

We actually talked about that in an article we did back in the August 2009 issue of VG.

Yes that’s right. That patina of rust on the core of your transformer is an indicator of better quality iron that is ideally suited for guitar tone. The rust itself is working in league with the iron to assure that level of tonal performance. Modern day technology messes with the original iron processing recipes by adding rust inhibitors and other fillers. They’ve short-cut the more time-consuming and costly metallurgical processes – just like how auto makers are putting in more plastic than metal in their cars. Iron is an amazing magnetic conductor until it gets diluted or polluted with things that are better suited for non-audio applications. So if I had my choice, I’d prefer to play an amp with rusty transformers delivering the tone I want rather than an amp with pristine rust-free transformers that make the amp sound like it’s got a sock stuffed down its throat.

So the original core will go back in the transformer?

Yes. Since you have the right kind of iron core we’ll reassemble it the way we found it, then retune it to the original factory specs. If you were stuck with a transformer that had inferior core material, then we would suggest swapping it with Mercury upgrade iron.

It’s come to our attention that many current production transformers marked with “Made in the U.S.A.,” are actually using offshore materials, i.e. magnet wire and steel. More accurately they should read “Assembled in the U.S.A.” These self-defeating transformers are good candidates for our upgrades rather than rewinds.

Cores are the first component out and the last in during the course of restoration. An interesting fact: cores are never at fault when it comes to a transformer breakdown. The core is removed solely for us to gain access to the coil of the transformer. Taking apart the coil is a surgical process that begins our forensic investigation – like the crime shows on TV. Unpeeling a coil is quite revealing and will tell us the story of what happened. Under interrogation the coil always tell us the truth. A body of a man is wheeled in to the morgue. His wife insists that he shot himself while cleaning his gun – but the autopsy’s evidence proves otherwise. Now she’s under suspicion.

Well the coil of your transformer quickly spilled the beans. Remember that small black spot we noticed on the outer wrap of the coil? Sometimes there are innocuous blemishes in the form of spots that may appear on the surface of paper and are nothing to worry about. However, what we normally find in fried transformers is that the burn begins somewhere in the middle of the coil and works its way out – causing an exit wound. In your case the failure was not typical. Yours was an entry wound.

This is important because it indicated to us that it was killed by a sharp instrument that penetrated the outer insulation that broke through and severed two turns of the fine wire that make up ½ of your primary winding. Meaning that only one of the two power tubes was operational. The damage to the entire transformer was limited to that spot and only the very top layer of the magnet wire. Those broken wires were arcing across each other and taking advantage of the oxygen available from the perforation of the outer wrap to form that black spot. Further evidence to support these findings is the fact that the rest of the winding, all the way down to the bobbin, was unharmed.

This type of injury is caused by the usual suspects – the installer or remover of the transformer. The smoking gun possibilities are: the tip of a soldering iron, the tip of a Phillips screw driver… or rough handling (dropping or bumping the transformer against something sharp, etc.) with enough force to puncture it to cause such a failure. And finally, we cannot rule out beer as another possibility.

You can now relax. Your tubes and speaker are now ruled out as possible components of interest.

What gets burned out in a transformer that you’re actually replacing?

The magnet wire. When its insulation gets over taxed the fuster-cluck begins as the insulation system of the overall coil progressively losses its integrity (dielectric strength) and begins to arc or burn.

Can you ever rewind a transformer with its original wire?

We certainly wouldn’t do it. When the tires of your car are worn out, do you go out and buy used ones to replace them? Unless you’re a former stockbroker, what’s the point?

Magnet wire is not bare copper wire. There is a micro thin coating of plastic insulation that protects it from shorting. That very thin layer of plastic is susceptible to microscopic spider web-like cracking. And the process of unwinding the magnet wire virtually assures it’s going to get damaged.

Check out the photo of what the magnet wire from your transformer looks like after it was unwound. Does this look like something you’d want to put back in your transformer?

Has any of the machinery used for rewinding changed over the years?

Most of our methods and equipment for rewinding transformers we consider proprietary. So I’m going to stay away from specifics. However, the basic concept of winding equipment hasn’t really changed for over the last 100 years. Today, of course, we see more computerized machines. But we chose to stick with the gold standard of vintage equipment

Aside from ours, I’d be surprised if there is any precision equipment available that is dedicated for the sole purpose of unwinding/rewinding. Most attempts at rewinds today just use run-of-the-mill winding machines that produce, at best, haphazard results.

So if someone gives you a prized “mojo” tranny, do you have the capability of rewinding it exactly the way it was before?

You know I’m not a big believer in mojo. I maintain that all things to do with amps and their respective tone can be easily explained and reproduced, and dare I say it… improved. But yes, we do have the capability. We treat all transformers with the respect and the dignity they deserve. Most people in this business wouldn’t treat these transformers with such reverence. Likewise, they may not have any musical background or an appreciation for electric guitar tone. We’re more than just a transformer company. If the original transformer included magical “fairy dust” or whatever that made it sound unique and desirable, we wouldn’t overlook it or change anything. That’s our promise.

We must be doing something right because we receive mountains of mail, email and phone calls from players all over the world who thank us for giving back (or preserving) their amp’s mojo.

When you begin rewinding, are you using the same wire that was used in the ’50s and ’60s?

That brings up a couple of interesting and important points. First, Mercury is probably the only company in this industry that uses high-purity OFC (oxygen free copper) magnet wire made in here the U.S.A. – which we use exclusively because of its guitar tone (as well as our hi-fi audio) properties. This type of wire is clearly sonically superior and more consistent than the wire that was used in the ’50s and ’60s. Wire technology back then was limited to about half of the temperature and electrical performance of Mercury’s standards. As a result, transformers using our materials last longer, take more abuse, are sonically more revealing, and follow a closer musical path when over driven into harmonics.

The second point is that we, as players, would much prefer the original wire from the ’50s and ’60s to the offshore and south-of-the-border suppliers of magnet wire. We gave them a chance, thinking we’d save some dough for our customers. The tested results yielded dull tone, inconsistent batches with too many instances of insulation breakdowns. Not even up to the standards of the vintage wire. Further, in real life tests of putting amps through their paces, the sonic differences were quite noticeably inferior to the guitar players here at Mercury and the players working for the recording studios here in southern California.

Have you ever seen a negative effect of age on a transformer?

In some cases yes. Sometimes your ears may pick up on affects of transformer aging before you realize what is happening. Dark, dull and fuzzy tones with a general sense of lower output volume.

If anything suffers from aging it will most likely be core. There are two major contributors that cause a negative effect of aging and affect your tone. Before World War II the science of processing iron was not up to snuff. It seemed that it was difficult then to boil out residual carbon from the iron. We are carbon-based life forms that age. We also rely on carbon for dating or aging organic compounds. Even a miniscule amount of carbon left in the older iron causes it to age. As the iron core ages, the magnetic conductivity begins to poop out, slowing the transformer’s responsiveness with increasing losses. The result is less output with only lower mids breaking through.

During WWII there was a shortage of iron for the war effort. So many transformer companies, in order to survive the hard times, made their cores out of soup can sheet metal! Transformers made this way were naturally plagued the wrong kind of iron and harboring plenty of carbon to boot. Do not confuse iron with steel. Finally, when silicon was implemented to help force out the carbon from post war iron, transformer iron became much more stable. Stable enough to out last us all.

Another contributor to transformer aging comes from humidity. Amp owners who live in humid climates have noticed their tone changing over the years. This is especially true if their older amps had transformers built around paper tubes. Paper-bobbins have always run the risk of moisture absorption affecting and changing tone. Conversely, we found that amps built with premium transformers that utilize plastic bobbins weren’t likely to suffer tone degradation via moisture saturation. A couple excellent examples would be the original Partridge and Radiospares transformers from England. With all the fog and rain they experience, these transformers have held up quite well.

Maybe this explains why coating paper in wax was attempted early on? To verify that dew point (humidity) affected output transformer tone, we had transformers from amps made in the ’60s, that had never left the U.K., flown in. They were provided to us by some of the best legendary players their country had to offer. They knew what their amps sounded like originally.

We put their transformers (all with paper bobbins) through a dehumidifying process, then re-sealed them in a generous varnish dip and a full bake. All these guys freaked out and thanked us for giving them their original tone back! And one of the player’s even called with a personal thanks that we had reaffirmed that he had not actually suffered hearing loss! He said that as time passed he noticed less treble tones and a lot less note separation and definition. Note attacks seemed impeded. Other players also had this mistaken belief that their amps were getting too old to play.

Obviously this new transformer won’t be dipped in wax like some of the old experimental ones. What will you use to insulate it?

Well, I wouldn’t call your transformer new. It’s still a 1960. If we had restored a 1960 Corvette for you, does it change the year, make or model? Instead of a fresh coat of paint for the car, your transformer will receive a fresh dip of glorious varnish. A non-flammable sexy coat of see-through clear. Something that may last long enough to pass along to your grandkids.

What can I expect the tonal differences to be between the rewound transformer and the original?

It should sound as good as when it left the showroom floor in 1960.

Your only other option, as far as upgrading the tone, would be to try one of our ToneClones. These are copies taken from some of the finest specimen celebrity-owned and played “pick of the litter” amplifiers. And it’s likely that you’ve heard these transformers in action on your favorite recordings.

Have rewinds come back to you shortly after you’ve sent them out?

On occasion, yes. Installer error happens, and if you don’t find and fix the problem that caused the transformer to blow in the first place, you’re just setting yourself up for a repeat performance.

Another thing that’s fairly common is the use NOS tubes. Usually purchased from eBay. We had a situation once where a customer, after installing his rebuilt transformer, decided to re-tube his amp with 40-year-old American-built originals. As luck would have it one of the NOS tubes shorted and caused a different failure in the newly rebuilt output transformer.

Is a rewind in store for every old transformer, or will they go on forever?

No, not every old transformer will need to be rewound if taken care of properly. Perhaps most may outlast the “Iron Age” of guitar amplifiers which we’re living in now. The push for solid-state technology is tenacious enough to replace tubes/transformer-based amps in the long term (perhaps within the next 50 years?). Tubes may go but they’ll have to pry the transformers from my cold dead fingers before I’ll give them up.

We recently put transformers of all kinds, old and new, to the test by volunteering to help out the flood victims in Nashville. We offer to test and restore any flood damaged guitar amp transformer sent to us free of charge. We encountered some pretty nasty stuff. Yet, less than 5% of them needed to be rewound! (Namely, transformers with paper bobbin insulation, or amps that had been turned on before the transformers were tested.) Some of the transformers that came in were from amps that had been submerged in raw sewage for weeks! The odor was so fowl that we had to air them out, and the staff actually had to draw straws to determine who was going to work on them.

Talk about your shit jobs.

Man, you got that right! Ah, but there’s nothing like the fresh smell of varnish in the morning to help one deal with that challenge. We did manage to extract the moisture and reseal these transformers with varnish. The sacrifices you have to do to help out fellow musicians….

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Last month, Sergio Hamernik, head honcho at Mercury Magnetics, walked us through the intricate process of rewinding a vintage transformer. This month, we dig a little further into the details of winding, materials, the ways age affects some transformers, and why some of them fail.

When you rewind a transformer, do you use the same wire used in the 1950s and ’60s?

No. We use high-purity, oxygen-free copper magnet wire made in the U.S.A., and we use it because of its tonal properties – it’s sonically superior and more consistent than the wire used in the ’50 and ’60s. Wire, back then, had about half the temperature and electrical performance capability of Mercury’s standards.

We, as players, would prefer to use wire from the ’50s and ’60s compared to offshore and south-of-the-border wire. We tried them, thinking we’d save our customers some dough, but test results yielded dull tone and we saw inconsistent batches with too many instances of insulation breakdown. The stuff was not even up to the standards of vintage wire. Further, in real-life tests putting amps through their paces, the sonic differences were noticable to the guitar players here at Mercury, and those working for the recording studios here in Southern California.

Have you ever seen a negative effect of age on a transformer?

In some cases, yes. Sometimes, your ears pick up on the effects of aging before you realize what’s happening – they produce dark, dull, and fuzzy tones with a general sense of lower output volume.

If anything in a transformer suffers from aging, it will most likely be the core. Two major contributors cause a negative effect of aging and affect your tone. Before World War II, the science of processing iron was not up to snuff. It was difficult to boil out residual carbon, and even a miniscule amount of carbon in older iron causes it to age. As an iron core ages, its magnetic conductivity begins to poop out, slowing the transformer’s responsiveness with increasing losses. The result is less output with only lower mids breaking through.

During WWII, the war effort created a shortage of iron. So, many transformer companies made cores from sheet metal, like that used to make soup cans! These had the wrong kind of iron and harbored plenty of carbon, to boot – do not confuse iron with steel! Finally, when silicon was implemented to help force the carbon out of post-war iron, transformer iron became stable enough to outlast us all.

Another contributor to transformer aging comes from humidity. Amp owners who live in humid climates have noticed their tone changes over the years, especially if their older amps had transformers built around paper bobbins, which have always run the risk of moisture absorption affecting tone. Conversely, we found that transformers with plastic bobbins weren’t likely to suffer tone degradation via moisture saturation. A couple excellent examples are the original Partridge and Radiospares transformers from England – with the fog and rain they experience, these transformers held up quite well. That may explain why coating paper in wax was attempted early on, and to verify that humidity affected output transformer tone, we flew in transformers from amps made in the ’60s that had never left the U.K., all with paper bobbins, and put through a dehumidifying process, then re-sealed them in varnish and gave them a full bake. The owners freaked out and thanked us for giving them their original tone back! One called to thank us personally when he realized it was his tone fading over the years, and not his ears! He said that as time passed, he noticed less treble and a lot less note separation and definition. Others had this mastaken belief that their amps were getting too old to play.

Obviously, the rewound transformer for the 1960 Vox AC15 we’ve been working on the last few installments won’t be dipped in wax. What will you use to insulate it?

It’ll receive a fresh dip of varnish.

What can we expect the differences to be between the rewound transformer and the original?

It should sound as good as when it left the showroom in 1960. The only other option, as far as upgrading the tone, would be to try one of our ToneClones, which are copies of the finest celebrity-owned and played “pick of the litter” transformers. It’s likely you’ve heard these transformers in action on your favorite recordings.

Has a rewound transformer come back to you shortly after it was sent out?

Yes. Installer error happens, and if you don’t find and fix the problem that caused the transformer to blow in the first place, you’re setting yourself up for a repeat performance.

Another thing that’s fairly common is the use of N.O.S. tubes, usually bought from an online auction. We had a customer who, after installing his rebuilt output transformer, decided to re-tube his amp with 40-year-old American-made originals. As luck would have it, one of the tubes shorted and caused a different failure in the newly rebuilt transformer.

Is every old transformer destined for a rewind, or could some go on forever?

Not every old transformer will need to be rewound, if taken care of poperly. Most may outlast the “Iron Age” of guitar transformers, which we’re living in now. The push for solidstate technology is tenacious enough to replace tube-/transformer-based amps in the long term. Tubes may go, but they’ll have to pry the transformers from my cold dead fingers before I’ll give them up!

We recently put transformers of all kinds – old and new – to the test by volunteering to help flood victims in Nashville. We offered to test and restore water-damaged transformers, and encountered some pretty nasty stuff. Yet, less than five percent of them needed to be rewound – namely, those with paper bobbin insulation or amps that had been turned on before the transformers were tested. Some transformers were from amps that had been submerged in sewage for weeks! The odor was so foul we had to air them out, and the staff actually had to draw straws to determine who was going to work on them.

You must have your share of unpleasant jobs….

Man, you got that right! But there’s nothing like the fresh smell of varnish in the morning to help one deal with that challenge. We did manage to extract the moisture and re-seal these transformers with varnish. The sacrifices you have to do to help fellow musicians….

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For decades, unquantifiable numbers of discussions have wrangled over the main ingredient of amplifier magic. Some amp gurus say it’s the vacuum tubes. Others swear by the capacitors. One question has always remained: Does the transformer have anything to do with an amp’s tone?

At Mercury Magnetics, founder Sergio Hamernik readily acknowledges transformers are a bit of anenigma. Nonetheless, he very firmly believes they are the true foundation of tone.

“They remain the biggest and most misunderstood black hole on the subject of amplifiers and tone,” he said. “But it’s really not all that mysterious. Get an amp’s magnetics right, and everything else falls into place.”

But what does a transformer really do? We recently spoke with Hamernik, posing that question along with a slough of others about the design, purpose, and effect on output “trannies” in guitar amps.

VG: How does a transformer affect the sound of an amp?

SH:A power transformer that’s underbuilt is much the same as an automobile with an under sized engine. Take two cars; one has a five-horsepower engine, the other has 500horsepower. Run them both to 70miles per hour. How long does it take the five-horse to get there?

In an amp, energy has to be converted into sound – and the quality of the transformer determines the quality of the rest of the amplifier. The better the power supply, the faster it will respond to the sonic demands of the player. It’s the amount of energy available; you don’t want to be waiting for the transformer to play catch-up with every note you pluck.

VG: A lot of players believe the main contributor to an amp’s tone are its vacuum tubes.

SH:Tubes are greatly influenced by the reactance of an output transformer and how it’s built. That’s why a Marshall amp sounds different than a Voxor a Fender. It’s the main reason why a Marshall has a distinct output transformer design. When you swap power tubes, the differences in tone are actually quite subtle. But if you replace the output transformer, you have a completely different-sounding amp.

VG: Does that mean some players put a little too much stake in“matched” output tubes?

SH:It’s partly true that you don’t need exactly matched tubes to get great tone. Often, you can get great tone with mismatched tubes if they’re at least operational. An old studio and touring trick was to swap power-tube positions, which often provoked the best tone. The trick was simply taking advantage of the differences in unmatched tubes!

So, while it’s important that tubes be tested for defects, they do not necessarily need to match. Tubes used for pre amp and phase splitters should, as a rule, be matched for balanced operation. The“imbalanced” concept is actually a fundamental design philosophy, noting differences between transformers built for hi-fi audio versus guitar tone.

VG: How’s that?

SH:Output transformers in amplifiers are highly reactive components. Not only are they reactive, they tend to be reactive in a lopsided way,which disturbs the tube into distorting in a manner we find pleasing for its musical qualities.

This introduces a key point; there’s a huge difference in design and execution between hi-fi and guitar amp transformer designs. In order for a guitar amp transformer to sound its best, certain imbalances must be built into its design. With hi-fi, you’re trying to get as clean and undoctored an output signal as you can, without distortion. The opposite characteristics –distortion, overdrive, “grind,” and“crunch” – are the cornerstone of what makes a guitar amp toneful. The term “clean” in a guitar amp actually means “less distorted,” but it’s still a distorted signal.

This reactive element of transformers running imbalanced is key to creating a complex soup we call ampli-fied guitar “tone.” When you’re making good soup, how thick or thin you cut the vegetables, the other ingredients you put in, all affect the flavor. The ingredients are often subjective, but in the end, the effort and attention to detail make all the difference.

Musicians were on the verge of losing the quality of their tone until some-body stepped in to utilize these fundamental principles. At Mercury, we made it out mission to gain the knowledge and craft of how to make guitar amp transformers.

VG: Do they still make transformers like they used to?

SH:No, with Mercury being one of the few exceptions. Consider the quality of the wonderful transformers of the 1950sand early ’60s, when manufacturers were still building to military specifications.

How could this happen. Well, transformers have always been the most expensive parts of an amp, somewhere around 50 percent of the costs. Not to mention they’re often heavy, which affects ship-ping costs. The folks responsible for purchasing face a lot of pressure to get costs down, thus maintaining the trend toward low-budget transformers. So it was inevitable that the “baby” – in this case, tone – got tossed out with the bath water.

Older transformers were designed to meet a power ratio of 6:1, 7:1, or even 8:1, the ratio meaning the power supply rating versus audio output rating. It wasn’t unusual to find 600 watts of power supply on a 100-watt amp. Talk about headroom!By the ’70s, though, price points started having more influence on product than did design, and power ratios started to slim down. Case in point; a popular line of amplifiers that made their mark in the ’60swere built requiring power ratios of 6:1 or8:1. By the ’80s they were dropped to 4:1,3:1, or even 2:1. Today a lot of transformers coming out of Asia are as low as 1.5:1!

Why is this important? Two main reasons; the first is that note separation and the amp’s punch-through characteristics depend on these ratios. The lower the ratio, the less dynamic and more dull-sounding the amp becomes. The second reason has to do with the operating temperature of the transformer. Many reissue amps have undersized transformers with low power-to-audio ratios. With as little as a half hour of play, many of these amps are running hotter than a bitch kitty.

Weak power supplies equate to weak sounding amplifiers. Understanding the relationship of magnetics to tone is the foundation of getting the tone thing right.

VG: Do transformers made with paper tube bobbins sound better than those with nylon?

SH:Paper bobbins will not rescue dull tone. Does wearing the right ball cap make you a better baseball player? Perhaps this myth started when someone compared a great-sounding vintage transformer that happened to have a paper bob-bin with a modern-day generic transformer with a nylon bobbin.

Paper tubes were a cost-cutting measure,first and foremost. They allowed a transformer manufacturer to easily wind more than one coil at a time. Back then, nylon bobbins were a high-priced alternative,but were recognized even then for superior performance.

Another problem plaguing paper bobbins are their sloppy tolerances, which make it difficult for any two transformers to sound the same. And paper tubes tend to collect moisture, which varies the reactive properties of transformer design, and thus,tone. We’ve proven this by taking transformers from highly humid environments and driving the moisture out of them. This procedure noticeably improved tone,brings back detail, and makes an amp sound less dull.

We have no bias one way or the other.Certainly, it would be less expensive to use paper. But we had some of the best studio players help us make the determination, and the choice was clear.

VG: How do you devise specs for transformers?

SH: We’ve been documenting designs for decades. Many include “happy accidents” and hidden treasure among the thousands of mediocre-sounding specimens. Our transformers are duplicates of those from the best-sounding amps in the world,many of which were literally one-of-a-kind designs donated by collectors and artists.

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Fiction: Transformers made to look vintage with paper tube bobbins (PTBs) somehow have better vintage tone than those using nylon.

Fact: PTBs were used in the early years of transformers only because they were the cheapest material available. Back then tone, consistency and long term reliability usually took a back seat to meeting a low budget. This still remains true today. If the issue of using PTBs for the sake of sounding more vintage was that simple then sporting a set of sideburns like Elvis should give you the ability to sing like him. Impersonators/imitators rarely scratch below the surface to find the heart and soul of what advances art and science.

Mercury’s goal of providing you with the finest sounding transformers on the planet could never be achieved by peddling myth, voodoo, junk science or unqualified opinion. The bottom line is that under close scrutiny PTBs fell short of our tonal expectations, not to mention the valued opinions and advice we’ve received from the finest players, recording artists, technicians and engineers of the past fifty years.

Let’s leave the question of paper or plastic to the box boy at your local grocery store. At Mercury we combine the best of what tradition has to offer with the best of today’s technology — and of course plenty of hindsight to boot. If you love music as much as we do, then you won’t settle for anything less than a set of Mercs in your amp — the best in tone without compromise.

Source: https://mercurymagnetics.com/pages/_misc/FAQ.htm#The_Paper_vs._Nylon_Bobbins_Myth_

Output Transformer Bobbins – Is Paper the Real Gold Standard?
I’ve heard it repeatedly: Paper bobbins on output transformers in tube amps are somehow better than plastic bobbins. Is this version of the adage “They don’t make them like they used to” true or false? Or, is it a bit of both?

Transformers used to be wound on cardboard formers, which were hollow “sticks” of glued-up cardboard about three feet long. The hollow within offered just the right dimensions needed to slip the transformer laminations snugly inside.

Winding-machine operators would place the bobbin-forming “sticks” onto big machines and then wind several coils at the same time, spaced out along the stick. Each separate section would be wound with primaries and secondaries, stacked atop one another just the way they would be in the completed transformer.

The finished stick was cut into sections, each section being long enough to hold one set of coils. These sections each became the entire windings for one transformer. That’s how the term “stick wound” originated in regard to those transformers. They were literally wound on a stick. Almost all the “golden age” transformers—the good and the bad–were made this way. It was simply the cheapest way to produce transformers in high volumes.

Transformer vendors eventually came up with the concept of using plastic bobbins for the windings. These bobbins formed a protective insulating layer on the ends of the coil, as well as between the coil and the core. They could also be produced on new automated winders at a cost that was even lower than stick-wound transformers. Manufacturers looking to reduce costs jumped onto the plastic bobbin bandwagon and wrung a few more cents out of their transformers.

Critical musicians, however, noticed that the new plastic-bobbin transformers didn’t sound as good as the old ones. Not surprisingly, they noticed the plastic bobbin and made the connection: Paper was good, but plastic was bad. Is that assumption correct? No.

The plain fact is that both cardboard and plastic are completely invisible to magnetic fields, and neither one makes any difference in the functioning of coils that are otherwise identical. The difference in performance is determined by how carefully the windings are designed and done, not which bobbin material is used.

It’s possible that sloppy winders adopted plastic bobbins to hide their work, but that has nothing to do with the bobbin. After all, it’s also possible to wind coils poorly onto cardboard. If the assembly worker is skillful and patient, then either bobbin material could be used with equal results.

On the other hand, something that really changes a transformer’s performance is something you never hear about: whether the transformer is impregnated or not. Impregnating the transformer—or, filling all the voids inside it–will always increase the unit’s self-capacitance because the air is replaced by varnish, polyester, urethane, beeswax, etc. A transformer that isn’t impregnated will always exhibit better high-end frequency response than an impregnated one that’s identical in every other respect. Technically, this is because air has a very low dielectric constant and the impregnating materials all have a higher dielectric constant.

So, is the way Leo did it better because he used paper bobbins? Sorry, but it isn’t.

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Seen the price of a vintage Marshall Plexi lately? Your three grand won’t guarantee a virgin circuit or great tone, but if real Plexi tone is what you’re all about, you can get there for a lot less, guaranteed. When TQR Advisory board member and Sheryl Crow guitarist Peter Stroud decided to make a Plexi from his late ’70s fawn 100W head, we enlisted the capable assistance of our main toneman Don Butler and the team at Mercury Magnetics, home of
the ToneClone line of authentic vintage-style replacement transformers. Mercury has blueprinted and reproduced nearly every vintage transformer made for guitar amplifiers, and they can rewind any blown transformer to exact, original specs and sound. So settle back and enjoy the following discussion and review of Peter Stroud’s successful conversion of a common (they built 1,000s) Marshall 100W into a stellar 100W Plexi.

TQR: What is the origin and general history of this Marshall amp?

Peter: I bought this amp about 10 years ago with the matching straight-front 4×12, 100 watt cab from a dealer down in Texas. It’s a ’77 Super Lead 100 watt 4-input. I was big into collecting the f awn-colored Marshalls at the time – a poor man’s custom color. Around the same time, I had learned how to work on my own amps from the standpoint of preventive maintenance and tone tweaking, so I converted the amp over to a cascade-style master volume circuit like a late ’70s head or JCM800. Eventually, I missed having the 4-input sound and put it back to its original wiring.

Don: This amp was a standard 100 watt, non-master Marshall from the late ’70s. Some mods had been done and then undone. A few coupling caps had been changed as well as a few resistors

Strengths: Semi-loud. Typical PCB Marshall from this era. Better quality glass board than what’s used now.

Shortcomings: Ceramic caps. This amp was voiced for brighter sound, less bottom, and quicker distortion onset that original ’60s versions didn’t employ. It still had a couple of the original filter cans. The amp sounded exactly the same no matter what guitar was plugged up to it – no tonal distinction between any instrument at all! Very over-emphasized, weird G string odd harmonics (most likely old filter cap related). I have to add from a personal note that this was the worst sounding Marshall I’d ever heard or played! In a word – no tone!

TQR: Describe the specific improvements that you wanted to make to the amp, both from a technical perspective, and sound-wise. What components were changed and why?

Peter: I don’t know why – from my monkeying around with it perhaps (laughs), but this Marshall just sounded like crap. Every time I plugged in I would end up turning it off – totally uninspiring. I replaced tubes and a cap here and there but resigned to the notion that it might be the transformers. I had replaced all of the power supply caps, but not the 50/50mf in the preamp circuit. It could have been that – who knows? But in any case, I would have thrown it on eBay had it not been for the color. Instead, I decided to make it a guinea pig. I’ve been messing around inside my amps again recently and have had a real desire for that 100 watt Plexi sound and the cleaner, fuller tone they deliver. This head was far from it! Having read the ToneQuest interview with Sergio about Mercury Magneticstransformers and poking around their website, I figured the fawn 100 watt would be the perfect amp for a conversion – change out the transformers for high voltage models reminiscent of the Plexis and wire it up exactly like a ’67. I was determined to demystify the whole Plexi thing once and for all for my own comfort. After seeing how Mercury Magnetics had “cloned” the power and output trannies of an old Plexi, I felt the missing link had now appeared. Then you stepped in and it mushroomed into a topic for ToneQuest, and a very deserved one indeed. Nothing better than to see if any Marshall can become a Plexi, especially since the latest prices on eBay for Plexis are more than I care to spend. I need amps that are bulletproof and easy to replace. I spoke with Sergioand Paul at Mercury and they eventually hooked me up with Don Butler. I was thrilled to have Don take over the job knowing his ear for tone and knowledge of Plexis. There were three CD’s I used as a tone reference: bootlegs of Cream in ’67 and Jeff Beck in ’68, and the Hendrix at Monterey Pop Festival album.

Don: Peter wanted the amp to sound like a mid-to-late ’60s Plexi 100 watter. More specifically – a ’67. I replaced all the little green (or were they grey?) ceramic caps with polyester tubular caps and replaced any resistors that needed to be changed with carbon comp types. Polyester caps were used in the ’60s in all Marshalls for the main tone and coupling caps. I know for the higher value caps in the pico farad range, Marshall generally used the ones from Lemco or RS that were a flat mica-looking cap covered in a baked on ceramic or wax dipped coating. I used silver micas for those in Peter’s amp. I like the smoothness and more transparent quality of silver mica. The original polyester coupling and tone caps that Marshall used in the ’60s were from a company in the Czech Republic called Iskra. I believe Phillips imported those to the U.K. Those are the ones everyone refers to as the mustard caps. I used Mercury’s Plexi 100 output tranny, 10H choke and 100W Plexi power tranny that provides the B+ with around 525V DC after rectification. In my humble opinion, Mercury makes the best sounding, most accurate and most reliable clone transformers on the planet.

I also used the FRED rectifiers in place of the little cheap-o IN4007 diodes for the rectifier. I like the way they smooth out the harshness of the treble frequencies and take out that mid range bump that’s common with a solid state rectifier in amps. They also seem to add more note clarity, harmonics, and detail to the sound and tone of an amp. I replaced the components, transformers and the remaining filter cans. I then converted the circuit to what was used in 1967 in terms of how it was wired and component values.

Really, it’s not much. On the first valve/tube you remove the wire coming from pin #8 and shorten it and solder it to pin #3. The cathodes on that tube were shared and went to an 820 W resistor with a 250mf @ 25v cap paralleled with it to earth/ground. The second valve/tube did not have a cathode bypass cap in those days – only the resistor. There was a .68 cap I removed from that spot. I also removed the .004 cap from the volume pot on channel #1. That cap makes the amp distort quicker, and usually at just “2” on the volume pot you’re out of clean headroom and well into distortion land. That’s not what Peter wanted or what the old amps were like. I also used two 0.1/ 600V caps coming out of the phase inverter vs. the .022/600V caps that Marshall started using in around ’69 to brighten up their amps.

On the later Plexis you will find a 500rf and 33K slope resistor on Lead models and a 250rf & 56K slope resistor on Bass & PA models. Most, if not all of the schematics I’ve seen for early 100 watt Plexis used the 250pf & 56K in the tone stack. Peter’s amp had the 500rf and 33K. I replaced the 33K with the 56K for more bottom and hit a mid point between the 500rf & 250rf and used a 390rf cap for the treble control. Not too bright and not dark. With Some Lead amps, you have to turn the treble off and even then it can still be too much. I’ve found that by using a 390rf you get a happy medium point where the treble pot is still useable. All I did was put the amp into what Marshall’s circuit was in 1967 and used the same values and type of components they used, with a few improvements like the FRED rectifiers.

TQR:What type and brand of tubes were selected and why?

Don: I used the Svetlana EL-34s, as I’ve found them to sound extremely close to what the old Mullard xf3s offered in tone, as well as reliability. I’ve compared them side by side in my old 50-watter and in my ’64 VoxAC-50 and it’s really close. Preamp tubes – I used the new Ei Elite gold pin 12AX7s. To me they sound very nice and close to old Brimars and Mullards. Don’t forget that the Phillips Electronics Corp. once owned Mullard and Ei among many other subsidiaries. Ei seems to have made an excellent attempt at creating a good sounding, reliable 12AX7 that they pre-test before sending out. My favorite 12AX7-type of valve/tube for Marshall’s are the Brimars, as they offer a bit of that aggressive old tone that Marshall’s are famous for.

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When Time runs into a dangerous power situation in an old Magnatone lap steel amp, he’s tasked with completely reimagining the project.

It seems as if almost all of our clients have at one time or another, purchased something online. Often a funky old guitar or amp that was acquired at, what seemed to be at the time, a decent price. We hear the same words uttered over and over again. I just got an amazing deal on this at e… (rhymes with hey) but I think it needs a bit of work. Often, the amount of work required to transform the instrument into something playable makes the “great deal” now seem like a thorough hosing. Sometimes items come with a trial period in which the buyer can return it if doesn’t meet his/her expectations. Other times the piece may be salvaged or kept, though unusable, simply because it has a certain amount of character that makes it worth having if only for a wall hanger.

This month we’ll be taking a look at one such project. It involves a Magnatone lap steel and amp set.

A client purchased a beautiful (and very early) Magnatone lap steel and amp set. They were brought into our shop to have a basic “check and clean” done to the amp and to have the lap steel repaired/restored. The lap steel needed to have the tuning machines replaced as the buttons had deteriorated to the point that they were now little ratty stubs that needed a pair of pliers to aid in the tuning process. A similarly styled set of Tone Pros 3-on-a-strip tuners were installed, scratchy pots were salvaged with a bit of electronics cleaner and some minor setup work was done to level the string heights at the nut.

The amplifier was powered on to see if it was working and to listen for any nasty noises that would need to be addressed in our “check and clean” procedure. Surprisingly, the amp sounded pretty darn good. It had a very unique character to the break up as the amp was pushed into distortion. The amp was then disassembled to check for leaky caps and resistors that may have drifted out of spec that would cause the voltages to swing to unsafe/improper levels. First I tried to locate the power transformer to get my bearings. Hmmmm, strange I thought, no power transformer! Then it dawned on me. This amp is running on pure AC!

While this isn’t that unusual in very early amps and it certainly contributes to its unique tone, it’s also very dangerous. One leg of the AC is tied to the chassis as a buss in the same way a ground would be in a more modern design. This would almost be okay if the instrument being played through it had the strings isolated from the electronics (though it’s still present on the metal chassis). However, in most modern guitars, the strings are attached to the ground. In this instance it means that the player now has one leg of the AC on his/her strings! This puts me in a rather precarious position. As the tech and owner of the shop, there are some obvious liability issues associated with this project.

The client was consulted and told of the dangers that lurked within this design. As he loved the look and character of the box, he gave me the go ahead to build a simple and more “modern” (late-’50s) design into the existing chassis. A promising schematic was found (a Valco of some sort) that used a 6SL7 octal preamp tube a 6V6 and a 5Y3 rectifier. This design was chosen simply because of its funky character, which was thought to be in keeping with the original design.

The build was a bit tricky as the amps chassis was quite small and was never made to carry the bulk of a power tranny. Every component was stripped off and the task of figuring out a layout that was physically possible, considering the tight space, begun. It was necessary to make a metal plate to cover a hole left by one of the tube sockets that had to be relocated to make room for the new Mercury power tranny. The output transformer had to be located inside the chassis due to lack of room caused by the speaker’s magnet protruding into the optimal space. New holes had to be drilled/punched for the input jack, transformers, IEC style AC socket and tube socket.

It’s freeing being charged with the task of simply making something funky that works. Certain liberties can be taken in component selection that wouldn’t necessarily be considered when shooting for a dead silent recording amp or a rock solid touring amp for example. I was able to use some really neat Soviet-era paper in oil caps that I found while traveling in Bulgaria last year as well as some interesting carbon comp resistors acquired at the same time. Fortunately, the original speaker was still in good shape and was reused.

Mission accomplished. The end result was a marriage between over-the-top vintage form and functionality. The amp was transformed into a safe and usable conversation piece and I’m told, gets many hours of use a week. While this project may not have been the most economical way to go about getting a small practice amp, it did end up salvaging a very cool set and making it safe and enjoyable for the proud and happy owner.

Source: https://mercurymagnetics.com/pages/news/PremierGuitar/PremierG-28.htm

Following up on the successful introduction of 65 Amps’ flagship London 18W, the company has launched its second model — the Marquee. Named for the legendary Soho music venue where every ’60s British band of note once honed their craft, the Marquee is a bigger-sounding, louder version of the London 65 in some respects, endowed with great headroom and presence. We asked co-founder of 65 Amps and Sheryl Crow guitarist Peter Stroud to describe the musical intention of the Marquee, and our review follows….

TQR: What inspired the development and design of the Marquee, Peter? What did you want to accomplish specifically?

Peter Stroud: We had guitarists loving the sound of the London, but still needing either more volume or clean headroom. Personally, I wanted an amp to replace the Super Reverb in my live rig with that Fender clarity, but more of the openness and touch sensitivity of an amp like the London. Our initial idea with the Marquee was to create a more powerful version of the London 18 watter using 4 EL84s. But we also wanted something with the midrange clarity of the British amps and the clean sparkle of the American Fender Blackface sounds — just not as hard sounding as the 6L6 cleaner tone can be. On top of that, it has a higher gain tone that really roars.

TQR: To what extent were some of the design features in the Marquee such as the cascaded twin-triode operating in pentode mode and the 6-way Color control inspired by vintage amp designs?

Peter Stroud: Our initial intention for the Cascode (note spelling) configuration in this amp was to find a sound similar to the pentode type EF86 tube we use in the London, but more quiet. Due to vibration and noise issues inherent with EF86 tubes, we were apprehensive using it in a higher powered combo. The cascode circuit, which utilizes a 12AX7, was popular in early hi-fi preamplifiers. It has a harmonic content similar to the pentode circuit but produces more even-order harmonics. Randall Aiken helped us greatly with this circuit and we’ve continuously tweaked it’s current configuration in our amp. The end result is a distinctly different sounding channel from the Treble-Mid-Bass channel — very warm and rich sounding. It sounds beautiful with single coils and 12-string electrics. So, the Marquee initially came from many inspirations. Dan (Boul) and I are big fans of the Selmer amps. A few years ago while on tour in the UK I had picked up a Selmer Treble & Bass 50 MkIII, which is the early ’70s silver metal front — the ugly one. But that amp sounds awesome, like a “British Fender Blackface” with two EL34s. We’ve since found a Mk I Treble ‘n Bass from the first year they were built.

The font end of the Marquee Treble-Mid-Bass channel was initially inspired by the Selmer, but it branched off quite a bit. We just aimed for that sound. There are also similarities with the Selmer front-end circuit and the early ’60s brown-Tolex Fenders. I know one of your favorite amps is that killer Vibrolux 1×12 you have. The (Marquee) power stage is a fairly typical British-style 4-EL84 circuit. From there we spent months tweaking the tone circuit. We wanted the Treble-Mid-Bass tone configuration for more control with a higher powered amp.

TQR: You’ve played just about every conceivable guitar amp and for years your rig consisted of a Super Reverb and Marshall 50W. To what extent does the Marquee succeed in giving you both the clean and overdriven tones you need at usable state volumes, and how do you use it specifically?

Peter Stroud: On the latest tour I used both a London and a Marquee and A/B’d between the two. The two together worked perfectly for our stage volume. I’d set the London for a slightly driven rhythm sound playing through an EF86 channel and would use the gain boost for leads. The Marquee took the place of my Super Reverb as my clean sound, and it proved to be better since the mids are more pronounced and you get the nice dynamic saturation of EL84s. It’s much more touch sensitive, which is hard to get with a clean sound without using a compressor. The only time I’d kick on both amps was for Led Zep’s “Rock N Roll,” which we play as an encore. I’d crank the Marquee to 6, hit the gain boost and boost the mids. It totally hit the “Pagey” kind of sound. You can dump the mids and boost the bass and highs and get a chimey sparkling clean tone — settings around 4 on the volume, treble and bass around 6 to 7 and midrange around 4. For a cranking rhythm I’ll set the volume around6, boost the mids to 8 or so, drop the bass around 4, treble at 5. There’s also a footswitchable gain, like on the London, so you can set a rhythm tone on the T-M-B channel and kick in the boost for lead. If you turn the amp up to 10, look out!

TQR: You mention “mustard” caps on your web site being used throughout the amp — are these modern reproductions of the original “mustard” caps used by Marshall in the ’60s?

Peter Stroud: Yes, we use the SOZO caps made by John Gaynor. John’s a Marshall enthusiast who has totally nailed (and surpassed, in our opinion) the “mustard cap” tone where you get the nice smooth mids and bell-tone clarity.

TQR: What else are you working on?

Peter Stroud: We have two new models in the works — a smaller “grab n go” 1×12 combo which actually incorporates a master volume with two EL84s. It has a great sounding master volume that has a sound of its own that can be disengaged so that the amp ha a non-master function. Sort of a “British Fender” vibe again. The thing screams, it can get chimey clean, and it’s incredibly versatile. And over the past six months, we’ve been developing a KT77 head using our Marquee as the springboard with a KT77/EL34 power stage. We had a handful of pro level artists who wanted extreme volume and headroom, where they were used to their 50 and 100 watt EL34 hears and quite a lot of volume. Plus, Dan is a big fan of the Vox AC50 and I’m the Marshall fanatic, so we got into that mindset again. We sent a prototype out for a test run with Rich Robinson of The Black Crowes and he ended up using it as his main amp for the entire last month or so of their tour. When we got it back, all the knobs were dimed. Couldn’t ask for better testing in the field! We’ll introduce both of these amps at Winter NAMM.

REVIEW — 65 Marquee

We spent a lot of quality time with the 35W Marquee Club, and it impressed us as a feisty chameleon that can gracefully move between big, jangly clean tones and an impressive roar with a deep palette of voices available from two very different input channels.

EL84 amps typically produce a distinct, musical compression characteristic that is absent in amplifiers using 6L6 output tubes, yet the Marquee produces gobs of clean headroom — albeit British headroom rather than the trademark 6L6-fueled fidelity of a Fender amp like the Twin or Super Reverb. As far as we’re concerned, British tone in an amplifier denotes rich harmonic depth and chime, often augmented with a dominant midrange emphasis, while Fender amps (Blackface models in particular, sound scooped in the mids by comparison with a wider, broader, looser feel and toner not unlike the difference between the sound of oooh and ahhh. In the Marquee, individual strings seem “closer together,” yet still well-defined throughout its range of clean settings. EQ coloration is accomplished in the “Classic” Channel bass/mid/treble/cut controls, and in the “Normal Channel via six EQ presets on a rotary switch. This “color switch” progressively thickens tone with gradual increases in lows and mids, but the Marquee’s chime and sparkle remain audibly preserved in every setting.

The Marquee produces moderate levels of smooth, overdriven tone at higher volume settings (+6) in the Normal Channel that can be neatly managed from the volume on your guitar, while the footswitchable Boost feature in the Classic Channel yields scorching distortion and sustain that nearly rival that of a Marshall JCM 900 Series Mk III. However, the Marquee delivers a chimier crunch rather than the more linear and cutting, laser beam focus of a high-gain Marshall. It’s a prettier brand of mayhem, if you will. And unlike many vintage British amps, the Marquee succeeds in delivery an enhanced range of both clean and overdriven tones, as well as a more versatile and varied range of EQ emphasis. Overall, we found it to be an inherently bright amp with the EQ controls in neutral settings, but you are also given plenty of room to shape the voice of the Marquee, from brilliant and clangy, to thick, heavy and imposing. We had no trouble dialing in great tones with all of our guitars — thickening the Teles and Stratocasters, planting a wet kiss of treble emphasis on the humbucking Gibsons, and alternatively mining the jangly clean chime and perfect meltdown of P90s. A potent rock amp that can cover a lot of ground, the Marquee is handwired with point-to-point construction that meets the high standards we have all come to expect from custom builders today, the transformers are custom-made by Mercury Magnetics, and the fit and finish of the cabinet work were flawless. As the name implies, the Marquee is steeped in the tones that defined modern rock & roll, viewed through a properly British perspective. And as Fender’s Ritchie Fliegler is fond of saying, “If this is what you like, you’ll really love this!” Quest forth, mate.

Source: https://mercurymagnetics.com/pages/news/ToneQuest/_2007/TQRJan07-2.htm

It only stands to reason that a guy whose day gig involves running his own successful and renowned pickup company knows killer tone when he hears it. So when the Jones hit to seek out a custom made map that combined the best of his favorite Blackface Vibroverb and Vibrolux, Lindy Franlin called upon Tony Albany and the guys at Vintage Vacuum Tube Amps to see if they might be up to the task. And that they were.

The holy grail would be to produce a 6L6 based 30 watt tone machine capable of a beautiful clean sound as well as a smooth, crunchy overdrive and be put captive into the smallest and lightest workable cabinet.

Beginning with a 2×10 Mojotone Tweed Super amp kit for the basic prototype, VVT and Fralin tweaked their hearts out for six months until they got it right.

Residing in a rather compact 20×20 cabinet, the VVT Lindy Fralin Model strikes a vintage pose in its white Tolex with oxblood-like grill cloth.

Beginning with a 2×10 Mojo tone Tweed Super amp kit for the basic prototype, VVT and Fralin tweaked their hearts out for six months until they got it right. Residing in a rather compact 20×20 cabinet, the VVT Lindy Fralin Model strikes a vintage pose in its white Tolex with oxblood-like grill cloth.

The VVT Lindy Fralin Model is a cathode biased straight forward, no bells and whistles affair. The “Plexi”top panel is simple and clean with its Input, bright switch, volume, treble and bass controls followed by the reverb control, standby and on/off switch. Chicken-headknobs let you know where you’re at. Two TAD matched 6L6 tubes supply the power with two 12AX7s for the preamp. A pair of 12AT7s are for the reverb driver and phase inverter. Rectifyin’ is courtesy of an Electro Harmonix 5U4GE. The cool thing is that the Lindy Fralin Model can also accept a deuce of 6V6s in place of the big bottles in the power section for a whole different vibe. Because of the higher plate voltages, VVT Amps stresses that only modern tubes (like the supplied JJ Electronics) should be used. You don’t want to blow the thing up, do ya?

If you think a 15 inch speaker might get as loose and floppy as your Auntie Mabel’s arse, you might be in fora pleasant surprise. With an obviously wider bass frequency range than a 12 inch, the Weber’sbottom remains tight and punchy with a nice lower mid section as well.Single coil and humbucker equipped instruments alike snuggled up quite admirably to the Weber Classic.

First impressions? The Lindy Fralin Model with my Strat spoke with gorgeous single coil chime and harmon-ic complexity, unabashedly magnified with a full trans-parent tone and organic beefy sustain. Very articulate and touch sensitive, the amp displays a more than impressive amount of projection. Both Lindy and Tony attribute this to the cross shaped members (called an integral diffuser) placed across the speaker opening in the baffle board which help disperse the sound and tame some of the“beamy” high end.

All tone controls are unobtrusive and very musical. While the treble is subtle up to around 6 on the dial, the bass is more evident from the get go but remains trans-parent throughout its range with no muddiness. The bright switch surrounds the notes and chards alike with an airiness without compromising the inherent full tone of the amp.

In addition to the Strat, the Lindy Fralin Model warmed up nicely to my other 6 string friends. The Carvin California Carved Top sounded sweet and detailed while my Ibanez AS200spoke with a very articulate, full and warm bodied tone.

Arch tops? This little box makes a nice jazz amp as well with clear, well defined chord structures and beefy single notes. With the fat axes pushing the volume past 3-1/2 caused a little mush in the low end which could probably be remedied by changing the first preamp tube to something with a bit less gain.

The reverb fills out the sound with a pleasant mix behind the dry signal. Throughout its range, the effect is very complimentary and doesn’t send your playing out to see even when dimed. For the dirty stuff, cranking the chicken head to the red(!) produced a bubbly, organic and throaty overdrive with real honest to goodness preamp/amp interaction. Very sweet with gobs of sustain. Doing a quick swap to the matched pair of 6V6s morphed the amp into a kind of Blackface Deluxe vibe with breakup noticeable at lower levels. The bottom felt a little less tight with a bit more perceived glassiness in the top end.

Whereas the 6L6 bottles speak “tux and bow tie” the6V6s are more “t-shirt and jeans”—not quite as complex but with a grittier and nice fat tone.

Also VVT Amps’ attention to detail gets a big thumbs up for the extra long line cord and groovy little spare fuse holder inside the back of the amp.

The collaboration between VVT Amps and Lindy Fralin has turned out to be a winning combination. The VVT Lindy Fralin Model’s beautiful, three-dimensional tones are equaled only by its straight-forward and no-nonsense design.

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When my love affair with the guitar began some 20 years ago, most of the bands that I loved and felt a connection with had something in common: the guitar sound that I heard was aggressive, yet refined. It would roar like a wild, untamed animal, yet have a gentle purr at the same time. I soon found out that the sound I was falling for was that of the Vox AC-30 amplifier and the EL-84 tubes that it uses. Over the years I have owned many amps in my search for that sound that I heard in my head. Some of the brands include Vox, Matchless, Fender, Marshall, Mesa Boogie, and Divided by 13, just to name a few.

Let me introduce you to Joe Morgan and Morgan Amplification. Joe is fairly new in the “boutique” amp scene, but has quickly gained respect and grown to become one of the most successful and talked about names in a market that is, if anything, flooded with amp builders fighting to make a name for themselves. I’d like to give you the lowdown on an amp that has (with good reason) become one of his most successful models – The AC-30 Deluxe.

The amps are all hand built and wired one at a time by Joe himself. It is a 20 watt, cathode biased, class A amp with a switchable 12AX7/EF86 preamp. It utilizes a GZ34 rectifier, Sozo capacitors and Mercury Magnetics transformers. The controls on the faceplate include Gain, Cut and Power Level knobs as well as Normal/Brilliant and Bright switches. The Power Level By Dwayne LarringMorgan AC-20 Deluxe Ampknob acts as a master volume, but it does so by adjusting the voltage to the power tubes, taking you from 20W down to 1W without losing the tonal qualities when you turn down the volume. This amp is available as a head or as a combo. The combo comes stock with a classic Celestion Blue speaker. The cabinets are made of 13 ply voidless Baltic Birch and are handmade by a master cabinetmaker who has worked previously in the Fender Custom Shop.

One of the first things I look for in an amp is: does it make all my guitars sound like themselves? I have owned amps in the past that have had such a distinct sound that they were more like the amp than the guitars that I played through them. Let me just say this: the AC-20 Deluxe loves guitars! I started by plugging straight into the amp, and then began playing with the knobs and switches. The first thing I noticed was that there isn’t a bad sound in this thing. It was like I was able to take a tour through the history of Vox amps. I was able to get tones that ranged from the classic, smaller sound of an AC-15 all the way through to the big, warm tones of the “normal” channel, and the shimmery tones of the “brilliant” channel on an AC-30. All of this was on the 12AX7 channel. When I switched over to the EF86 channel things started to get even more exciting! Remember when I referred earlier to that “sound” that was like the roar of an untamed, wild animal? Well, I found it! If you’re not familiar with the sound of an EF86 you could just consider this the “more” switch. You can really feel the low-end bolster up and the highs get more chirpy and chimey, as well as a defining of presence and punch in the mids. Factor this in with the fact that you still have the tonal variations of the Normal/Brilliant and the Bright switches, and you really have a versatile beast on your hands.

The real test for me comes when I plug in my pedal board. I dial up a basic tone that is clean when you play with a light touch and that starts to bark at you when you dig in. This posed no problems whatsoever for the AC-20 Deluxe. I also like to use boost pedals to achieve different levels of distortion/overdrive. When I tested this out this configuration, I was very pleased with the way that the amp handled the stacking of the gain stages that ranged from clean boost, to overdrive and crazy fuzz. I never got the feeling that it was too much for it to take.

The real kicker and deal sealer for me is the “Power Level” control. You may think that it is just a good master volume but in fact, it is way, way more. It is actually a built-in Variac (voltage regulator) that controls the amount of voltage the power tubes receive. When it is wide open it is running at the full 20W. As you start to turn it down, the wattage of the amp drops and your volume decreases. What’s so special about that, you ask? Well let me tell you. With this feature you are able to dial in your tone, and then control the output volume without changing that tone! By decreasing the voltage, the tubes still act and sound the same, just at lower or higher volumes. This is absolutely genius, and in my opinion, one of the most useful features ever to be put in an amp! Now you won’t have to deal with the soundman wanting to take your amp off the stage, or having to turn your amp down to the point where you completely lose all of your tone!

If you are looking for a real amp that sounds amazing, is hand built, versatile, and won’t break your bank… this is the one! Top that off with the fact that you have the choice to order this as a combo or a head, and have many different colors to choose from to find the perfect one that’s just right for you! Overall, this amp is a winner! Morgan Amplification AC-20 Deluxe 1×12 combo with Celestion Blue – Retail $1,900

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Hey, Jeff.

I love your column! I look forward to reading it every month. I have a ’67 blackface Super Reverb that I gig with. Really an awesome-sounding amp!

I just realized that the output transformer has been changed to a Bassman reissue or a Super reissue OT (output transformer). I’m not really big on keeping it original — it doesn’t really matter to me because I will never sell this amp — but like every other tone searcher out there, I want the best possible tone that this amp can achieve. I am curious about changing this out for a higher-quality OT. I heard the Mercury transformers are really good vintage replacements. What kind of differences in sound/tone will I hear by doing this, and is it worth it? Also what kind of tubes do you prefer in these amps? Thanks so much, and keep the awesome columns coming!

Ben

Hi Ben,

Thanks for reading PG, and thanks for writing in. It’s the much-appreciated support of the readers that enables all of us to write for such a cool publication. Now… on to that horrible amp you’re forced to gig with. I kid, of course. The Super Reverb is absolutely one of my favorite amps. The multiple 10″ speaker configuration helps give it a unique voice and sets it apart from most other combos using the ubiquitous 12″ speaker. It’s a shame that the output transformer needed to be replaced, but occasionally these things happen. A reissue Bassman or Super Reverb transformer, since they both have an output impedance of 2 ohms, will certainly get the amp working properly, but yes, you can do better.

Mercury Magnetics offers a couple of different lines, and they are some great-sounding replacement transformers. Their ToneClone series transformers are replicas of the original transformer designs, and the Axiom series takes them to the next level with design modifications for tonal improvement. Which one you choose will depend on whether you desire to have the amp sound as good as a great-sounding Super Reverb can, or to, as Emeril Lagasse says, “Kick it up a notch!” Either way, you should notice tonal improvements. Some may be very noticeable, and some may be subtler. Things like tighter, extended bottom end, smoother top end, more harmonic content and better note definition are all improvements you might expect. These attributes can all be affected by the quality of your output transformer. Whether it’s worth it or not is completely dependent on any cost limitations you put on your search for the ultimate tone.

You also asked about tube preference. This is always very subjective and depends on the type of music you play and your expectations of the amp. In general, my preferred preamp tube for amps that were not designed with heavily overdriven preamp sections is the Sovtek 12AX7LPS. Its large plates seem to make it a very full-range tube, so your guitar or effects will be very full bodied. In amps with major front-end gain, this extended frequency range can become too much of a good thing, but that’s certainly not the case with a Super Reverb like yours.

Also, here’s a little helpful tip to remember: Even new tubes can be microphonic. If you install new tubes in your amp and you experience ringing or feedback when the volume is turned up with nothing plugged in, try swapping the positions of all the tubes of a same spec. (In this case, it would be the 12AX7s. The 12AT7 tubes in Supers are in locations that are generally not too susceptible to microphonics, so they shouldn’t be an issue.) Certain locations in the circuit are more susceptible to microphonic tubes than others, so moving them often clears up the ringing, or at least minimizes it.

Preference for output tubes is much more dependent on the use of the amp and style of music. If you play mostly blues or classic rock, I would recommend going with a smaller-bottle tube that will have a nice, smooth breakup that occurs sooner — making it easier for the output stage of the amp to be pushed into clipping and achieve that glorious nirvana that is output-tube distortion! Recommendations might be the new reissue Tung-Sol 5881 or Groove Tubes GT-5881C. If you’re more into big jazz chords or country twang — or if you get your signature tones from stompboxes and prefer that the amp be as big, loud and proud as it can be — you’ll probably want to go with a larger-bottle tube. This generally yields the fullest, cleanest performance. Recommendations here might be the JJ/Tesla 6L6GC or the Ruby 6L6GCMSTR. Another suggestion here might be the new reissue Tung-Sol 6L6GC-STR. I just installed a quartet in a Twin Reverb and it was surprisingly loud ‘n proud. I hope that helps you on your way to a more super Super.

In this issue we are dealing with a subject on which I have received many inquiries in the past. It is about the selection or matching of tube amps for the best possible Jazz sound. Amplifying acoustic or semi-hollow-body guitars has always been a huge challenge because most jazz guitarists are very demanding in terms of sound and simultaneously fight against unwanted distortion and feedback. In the following article I would like to summarize some tips and tricks that get  great tone and how to avoid distortion.

When I started getting involved with jazz sounds, around 1977, most guitarists in this genre used transistor amplifiers. George Benson played a Polytone, Pat Metheny an acoustic amp with a 4×10” speaker cab and Volker Kriegel and Michael Sagmeister used a Gibson LAB L9 with 15” speakers. Such examples can be found very often from that period. Although all of these guitarists had indeed very good tone, the typical depth and openness of a tube amp sound could not be reached however in its wider spectrum. Still the transistor amps had some advantages over tube amps: They sounded very compact and linear, were less prone to feedback and offered a relatively balanced frequency spectrum and a nice sustain, which was the ideal sound of many jazz guitarists. A Gibson L5 played through a LAB or a Polytone is completely convincing – even today.

One disadvantage that the transistor amps had in particularly was its dynamic behaviour, in their relatively poor response and in their tendency to not let the individual character of a particular guitar fully unfold. You could also say: Transistor amps tend to standardise tone.

I do not wish to start a discussion about tube versus transistor because transistor amplifiers will continue to play a rightful role in jazz. It is more about ways to show how one can get the typical warm jazz tone with a tube amp without all the disadvantages.

Above all I am thinking of the sounds of the early sixties, which were marked by numerous jazz guitarists including: Wes Montgomery, Kenny Burrell, the early George Benson, Herb Ellis, Joe Pass, Barney Kessel, Grant Green and Jim Hall. All of these guitarists were playing tube amps on their early recordings and getting fantastic sounds. Today tube amps are celebrating a renaissance with jazz guitarists.

Let us first take look at the most popular models from the distant past. In the fifties the combos from Fender (Tweed), Gibson, Standel or Flot-A-Tone were especially loved by jazz musicians due to their sound and their small size. These amplifiers were sufficient for jazz guitarists because they were usually accompanying musicians and they performed as a soloist only in rare cases. They often stayed in the background and did not play very loud.

Even back then, most jazz guitars were equipped with a tone control that made it possible to filter out unwanted peaks and thus to form the typical dark jazz sound. But soon the guitar became a solo instrument. Just think of the impressive sound of a cascading Les Paul, who at that time had good reason to play on a solid body. The traditional jazz players remained with their hollow bodies and now had to fight against all the disadvantages of the electrification of their sounds. Recently I read in a retrospective of Wes Montgomery that he alleged that during his entire career he was unhappy with his sound because he simply could not find the perfect amp. One might even go so far and assume that the dark jazz sound is actually created only (and eventually cultivated) because the amount of unpleasant highs tube amplifiers have, are rather imperfect sounding and also quickly led to feedback. Most guitarists wanted more of a linear and natural reproduction of their beautiful instruments that already sounded great acoustically.

Let’s now take a look in the interior of a tube amp and consider certain circuit characteristics which can be modified for a better jazz tone. The objectives of these measures are the reduction of distortion and the high frequencies, improving the mid-range and increasing the linearity of the sound.

First, a list of known suitable amplifiers for conversion to a “jazz box”: Fender Tweed Fender amps from 1956 and Brownface, Blackface and Silverface combos. Examples from this list shall be explored in following issues.

Let’s start with a Tweed Deluxe amp replica from Cream which I have converted for jazz sounds. These amps are known for their distortion when left stock and therefore not ideal for a clear jazz tone. But they are very small and handy and with around 15 watts of power ideal for use in a club. In addition, these amplifiers are connected with a so-called “split-load” phase inverter which is appropriate for our purposes because of its low gain. The only drawback is the two coupled volume pots, which restrict the volume control range on the one hand and deliver too much gain in the preamp. The aim is to reduce the gain in the preamp and increase the output power and stability of the amplifier. Only then we get enough headroom for a clear sound.

Just this once, I should like to “put the cart before the horse” because there are a number of measures to improve the amp without intervention on the circuit.

First, these amplifiers usually have an inefficient speaker. Powerful speakers with a good efficiency rating are especially suitable for jazz sounds. Those who love the Alnico sound can search out an old JBL D-120 and replace the aluminum dust cap with a counterpart out of fabric (available from Weber VST). The speaker can be helped dramatically in the highs and we get a warmer, rounder tone. Excellent was also the old Fane Crescendo Heavy-duty speaker, which is also suitable after the removal of the aluminum dome making a perfectly clear and powerful sound. These speakers were also used by David Gilmour. Another excellent choice is also an Electro-Voice 12L or a Jensen C12K with 100 watts. All these speakers better the sound of the Tweed Deluxe significantly. You only have to watch out for the thin baffle-board because vibration during transport could for example pull heavy speakers from the screw holes.

A further stabilizing method is the conversion of the power tubes to 6L6 or 5881, which I recommended at this point several times. Although the amp has only about one or two watts more output, the increase in headroom is very clear. You get more clean reserves and dynamics. Here I recommend changing the cathode resistor of the amplifier from 250 (typically with 5 watts) to 330 ohms with 10 watts. If you play a jazz guitar with humbuckers, we recommend the low input of the normal channels. Here there are less highs and the output signal of the guitar is more attenuated. It should be noted that the volume pots affect each other on the Tweed Deluxe. By turning the unused channel by not more than 70 percent, the tone is much cleaner, but also quieter.

If you don’t wish to utilize this trick, you can simply remove the cathode of the second stage capacitor (Elko 25mF/25 volts) and reduce the gain of this stage substantially, which in turn increases headroom. The amp will be clearer and somewhat linear, but also a touch softer.

Even more clear sound can be obtained by replacing the output transformer. Something I always do in such tuning. In this case I choose a Mercury Magnetics Tweed Pro Axiom FTPRO-O transformer (available at Tonehenge Amplification) with 8 ohms, which gives much more stability to a small tweed amp.

If you want to use the amp only for jazz, you can also decouple the two volume controls from each other and only one channel and a tone control remain. Now you can adjust the volume much finer and linear. The circuit can be found at www.schematicheaven.com under Fender Deluxe 6G3. Here the channels are completely separate, each with their own volume and tone control. It’s only after the volume knobs on the channels that two 220k ohm mixing resistors are mixed together again.

Since the Tweed Deluxe played with humbuckers has in general somewhat bassy sounds, I also reduce the value of the coupling capacitors from 0.1mF to 0022mF. This makes the sound tighter and more mids. Sprague “Orange Drop” P715-type fit perfectly here.

Finally we get to fine-tuning via preamp tube placement. With a good 12AY7 and a 12AX7 of your choice, you can continue to shape your favourite tone. For those of you who have not had enough, you can play with the value of the capacitor on the tone-pot. The Deluxe was originally installed with a 0005 UF capacitor but also possible are values such as 0.01mF or 0.02mF (as in the 6G3) for a slightly warmer tone. If you want to darken the sound one can bridge one of the anode resistors at the 12AY7 with a 0.003mF capacitor (as in the normal channel of the Brown Vibrolux).

The result is a truly compelling jazz amp for small clubs, feeds back less, offers more clean reserves and could compete with any Polytone but all the benefits of dynamic and harmonically rich tube sound can be enjoyed. Diana Krall’s guitarist Anthony Wilson often used a Tweed Deluxe replica from Clark and his blond Gibson Byrdland in the studio. This sound is very reminiscent of Kenny Burrell and offers a wonderfully unique character. Have fun experimenting!

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A few years ago the guitar playing community experienced a resurgence of low-wattage amps. I’m not sure if it was because of the weight or the sheer volume larger stacks delivered, but the search was renewed for amps that could provide the same tone at an easily manageable weight and sound levels that didn’t make bartenders/engineers/wives scream, “Could you turn that down?”

This brought renewed interest in an obscure Marshall amp, the model 1974, an unassuming 18-watt combo. Originally available as a 1×12 — and closely related to the 18-watt model 1958 (2×10) and model 1973 (2×12) combos — the amp featured two EL84 power tubes, three ECC83 preamp tubes and a 6CA4 (EZ81) rectifier tube. There was even a rare reverb-equipped model, but all of the amps featured both a normal channel and a tremolo channel. The magic of the model 1974 was that with just a Les Paul and a cable players could approximate the beloved Eric Clapton “Beano” tone used on the Bluesbreakers with Eric Clapton album. Although I should note that Eric actually relied on a JTM45 combo, interest in the Beano tone ensured the 1974’s place in guitar lore. As was to be expected, clones of this amp began popping up rapidly once the originals, now extremely rare, began fetching prohibitively high prices.

I was fortunate enough to have quite a bit of exposure to these early Marshall amps, having worked with a shop that had no less than six of the model 1974s in stock during my tenure. One exceptional example was retained for studio use. A number of renowned guitarists had used the amp over the years, and they all agreed that it was one of the best — if not the best — they had heard.

A few months ago I was invited to Houston, Texas, by guitar legend Billy Gibbons, to bring a 2×12 Marshall model 1973 to the studio for a new ZZ Top album. Billy is an avid fan of 18-watt amps and has numerous clones to choose from, in addition to two original 18-watt Marshall combos. While we were listening and comparing sounds, I noticed a green Tolex 2×12 combo called the Retro-King 18 Watt sitting in the studio. Once he plugged into it, I knew both the original of the tone and that I had to check one out for myself.

King for a Day

The Retro-King 18 Watt is a completely custom-built amplifier, with the features you would expect to see in an amp of this class, including a solidly built, Baltic birch cabinet and handwired point-to-point construction. The fit and finish on everything from the cabinet to the Tolex covering was impeccable. The model I tested for this review had a 12″ Mojo Tone British Vintage Series speaker, although builder Chuck Dean will install others by request. The entire enclosure is substantial and provides for a big box tone from a single speaker combo. An impedance selector is included which is great for those planning to use this amp with other speakers or additional cabinets. The transformers are custom-wound to original Radiospares specs (an optional Mercury Magnetics transformer is available by request).

The 18 Watt has a couple of different features that I found to elevate this amp above some of the other 18-watt clones currently available. First, is the Master Volume control. You may ask why a Master Volume is needed for a low-wattage amp; while it does function to reduce the volume when the amp is cranked (bringing us back to that whole bartender/engineer/wives problem), it more importantly regulates how hard the power section is hit by the preamps. How the power section is driven affects everything, including the tone, overdrive and response of the amp, making the Master Volume a critical part of the circuit. The 18 Watt’s Master Volume circuit does not feel or respond like other Master Volume circuits I’ve heard; this one allowed me to get a wide variety of classic 18-watt tones, as well as the sounds of other model 1974 clones on the market. The Retro-King also features a tube biased tremolo like the original — it sounds wonderfully authentic, deep and a little Voxy. A footswitch proved to not only turn the tremolo on and off but to select between two speeds.

The second unique feature packed into Retro-King’s 18 Watt combo is a switch that allows for the selection of a tube rectifier or solid-state diode. The diode setting, while obviously not an original Marshall feature, provided more definition and headroom than the tube rectifier. When tube rectified, this amp has that sweet sag and compression that blues players love. If a player buys this low-wattage combo but is more accustomed to larger amps, this innovative feature will make it fee4l a bit more familiar — definitely a nice touch.

Of course, not all potential users of small amps are blues players. As a matter of fact, when I hooked the amp up to a Marshall Guv’nor pedal and set it for a very clean, high-headroom sound I was rewarded with a great rock sound. The tone was similar to Gary Moore, or even a bit more intense than that, if needed. The amp’s overdrive without a pedal ran from Black Crowes territory to the always-wanted, rarely granted “Beano” tone. Also surprising was that a Strat sounded excellent through this amp — something that I haven’t consistently found in other clones. The harmonics are rich, a la Billy Gibbons, especially when using pick harmonics. The 18 Watt cleaned up nicely and captured my picking dynamics perfectly.

The Final Mojo

I found the Retro-King 18 Watt 1×12 to be louder than the real thing, but with an authentic rendering of the actual tone for which these amps are famous was always there. I was also able to get higher-headroom, punchier tones that I was not able to get with the original. The original produced a slightly more compressed tone when driven hard with humbuckers but this would not have been obvious if the original had not been sitting right beside the Retro-King. In fact, the tones were so similar that I would have been guessing which one was which in a blind taste test. All in all, the Retro-King is more versatile than most other 1974 clones, without sacrificing the reason one buys an 18-watt Marshall-type amp in the first place.

Source: https://mercurymagnetics.com/pages/news/PremierGuitar/PremierG-12.htm

Marshall’s famed 1960s “plexi” and early-’70s 50-/100-watt amps gained notoriety for their fantastic tones. Of course, the downside was that they had to be driven hard to sound their best, which to the player (and anyone else in a milewide radius) meant volume – a lot of volume. And that sometimes meant turning speaker cabinets toward walls or employing an impromptu blanket muffler, sacrificing tone for the sake of band harmony and/or the mix. Then there was the consistency factor from one amp to the next, which meant hunting down the best-sounding Marshalls became an expensive game.

In short, when it comes to plexi tone, maybe those weren’t the “good old days.” Perhaps now, in our world of reissues, reproduction, and boutique guitars and amplifiers, guitarists are indeed in the midst of a golden age. If you doubt that’s the case, let us introduce the Voodoo Amplification V-Plex.

Voodoo Amps was founded in 1998 when hardcore tone lover Trace Allen Davis, a professional guitarist and proficient guitar/amp/pedal fixer, began modifying amplifiers. Largely dissatisfied with the offerings of the day, his idea of good tone caught on, and he quickly earned a reputation as a capable, comprehensive amp repair/modification shop.

We were offered a listen to the 50-watt V-Plex with Voodoo’s propriety-design 4×12″ slant cabinet. The hand-wired V-Plex is a four-input/two-channel amp with three 12AX7 tubes in the preamp and two EL34s in the power section. It has a single set of controls for Presence, Bass, Middle, Treble, Master and Volume – a layout identical to that of a vintage non-master-volume Marshall. The V-Plex’s Master volume is placed between the phase-inverter tube and the power tubes, which gives the player the ability to dial in plexi-like distortion starting at a very reasonable volume. On/off and standby switches, along with a red indicator, also occupy the front panel.

A look inside reveals flawless workmanship and top-quality components. Davis is, as we said, very much about the look and feel of guitar tone, and the research he put into this head is glaringly obvious. The cabinet uses four Celestion G12M “greenback” speakers, which are seen in amps all over the place.

But Voodoo’s cab is a little tricked out; aside from its propritary internal design, it is also capable of operating at either 4 ohms or 16 ohms in mono, as well as 8 ohms in stereo.

No doubt about it – the V-Plex talks the talk. But to see whether it walked the walk, we recruited a Schecter 006 solid body with two high-output humbuckers, and a Fender Stratocaster with three Duncan Alnico single-coils. We plugged in the Schecter and started with the V-Plex’s controls set in a familiar plexi manner; Bass at 10, Presence at 4, Mids at 6, Treble at 2, Master between 8 and 9, and Volume pushed to 8.

Flashback

If you’re a fan of the original Marshall JTM 45/50/100 models (if you’re a fan of real rock guitar tones, that’s you!), plugging in the V-Plex could well be the ultimate experience, especially if you’re not hip to coughing up the money to obtain (and hassle to care for) a vintage Marshal. Tone – gain-rich harmonics, with that clear, articulate crunch we’ve come to lust after – spews from the V-Plex by the truckload.

To test the effectiveness of the Master volume circuit, we rolled off the Master and brought the Volume control up a touch, and heard fistfuls of rich gain at reasonable SPLs. Yes, Virginia, you can get great plexi tone at comfortable levels.

The tone knobs reacted almost exactly like those in the original plexi circuit in that they don’t alter the tone much, but produce different textures. Backing off the volume and increasing the Master yielded a cleaner crunch that never surrendered its true character. “Jumping” input channels (a favorite trick of four-input-Marshall owners) substantially fattened the tone.

We next plugged in the Stratocaster. To keep high-end response where we liked it required rolling back the Treble and Presence controls, but the Strat also proffered fat, meaty tone from every pickup and selector-switch position. Crossing channels again, we got more meat right up until we pushed it too hard, when (in true plexi form) the signal compressed beyond the point of being enjoyable.

If you’re after the ultimate vintage plexi tone, your search could very well end right here, as the Voodoo V-Plex delivers definitive plexi tone, and has the ability to play at comfortable levels. Davis and his crew nailed it. – Bob Tekippe/Ward Meeker

VVT’s Lindy Fralin Model amplifier

Maryland-based amplifier builder Vintage Vacuum Tube Amplifiers (you may know it as VVT) recently fielded a request from renowned pickup winder Lindy Fralin. He wasn’t looking for advice on wire or how hot to wind a pickup for best interaction with a particular VVT; rather, Fralin wanted an amp built to his specs and taste. And not just for him, but for the mass market. VVT, realizing the co-branding possibilities, jumped at the opportunity.

So, what does a tone guru like Fralin want in an amplifier? Well, he says the goal was “a clean, full-body-voiced amp that’s lightweight and able to sound good at low volume.” Sounds like something we’d like, too. So when VVT asked whether we wanted to hear it, we were happy to take up the offer.

At first glance, the VVT Lindy Fralin amp looks boutique in a way we’ve come to expect; i.e. it sports point-to-point wiring with carbon-comp resistors, an all-tube circuit, and a 12AX7-driven spring reverb and preamp. But, go deeper and you’ll quickly discover some seldom-seen features, like a trick self-biasing-cathode design that allows the player to switch between a pair of 6L6s (for 30 watt of output) and a pair of 6V6s (for 15-watts) without having to re-bias the amp. Part of its secret is a custom-wound Mercury Magnetics transformer designed specifically for the Fralin that allows the amp to switch between the 6L6s and 6V6s while maintaining stable impedance for the tubes and speaker load.

The amp ships with a pair of 6L6s, but will also accept 5881s or JJ 6V6s, for an altogether different favor. Another unique feature is Fralin’s choice of a single 15″ alnico-magnet Weber speaker instead of the more traditional pair of 10″ or single 12″ speaker.

The overall look and layout of the amp is different, as well, but still boasts a vintage vibe with a neatly executed off-white tolex, oxblood grille cloth, top-mounted controls, and heavy-duty leather handle. There are no metal or plastic corner protectors, and no extraneous piping or badging. Its look is clean, simple, and classic. The control layout is accordingly succinct, with a single 1⁄4″ input, a switch for Bright, and controls for Volume, Treble, Bass and Reverb, along with switches for Power and Standby. Also worthy of mention is the 11-foot power cord.

VVT shipped our tester with a matched pair of 6L6s by TAD and a matched pair of 6V6s by JJ. We started with the TAD 6L6s and our test guitars – a Fender Relic Strat and a Hofner Verythin Classic with mini-humbuckers. After plugging in the Relic Strat and letting the amp warm up, we set the Volume at 3 o’clock, Bass and Treble at 12, and then we hammered a few chords.

We were immediately impressed with the amp’s complex overtones, its round, punchy low-end response, and its snappy highs. It didn’t take much noodling or knob tweaking to realize that the tone controls on this amp, along with its Bright switch, are exceedingly well-voiced. From a player’s perspective, that means it’s easy to find likeable sounds. The Bright switch compensates nicely for the slightly darker sound of mini- or full-size humbuckers, while the wide sweep of the Bass control keeps its frequencies full and punchy with single-coils.

While the amp is voiced for clean tones, it also does a good job when it comes time to get dirty, and is very responsive to changes in pick attack or guitar output. Simply backing down the volume control on the guitar and easing up on our pick attack, the Fralin cleaned up from moderately dirty overdrive with musical overtones to a sparkling clean sound that didn’t lose any of its life or attitude.

We popped in the matched set of JJ 6V6s and checked the tone at 15 watts output. The amp broke up quickly and had a slightly more boxy sound, with reduced complexity of overtones; still very lively and punchy, just not as big as 6L6s – fantastic for low-volume situations. The tube-driven reverb is also well-voiced. At lower settings, it adds a bit of ambiance that doesn’t get in the way or wash out the amp’s tone, and at higher settings it’s suitably splashy.

The boys at Vintage Vacuum Tube do a killer job on the Fralin signature amp. It’s loaded with big, dynamic, single-coil-friendly tone (that sounds pretty good with humbuckers, too!) in a nice, lightweight package. – Phil Feser

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Let your ears re-discover and re-experience real vintage tone. Imagine having an unlimited budget (and time) to play thousands of amps — including the often spectacular specimens held in private collections all over the world. Then from this exhaustive search you get to pick the one or two that have THE sound.

ToneClone transformers are exact genetic duplicates from these sought-after amps. Many came from amps owned by your favorite players. The same amps that were used to record some of the greatest electric guitar songs we’ve known.

That’s why Mercury constantly seeks only the best-of-the-best transformers to add to our catalog. When an exceptional transformer is discovered, it is carefully studied, analyzed and duplicated. Mercury engineers clone every detail and nuance of these best-of-breed transformers — a process we’ve been refining and improving upon for decades.

ToneClone transformers are designed for upgrades, replacements or custom-built tube-based amps. ToneClone transformers come with both our 10-year Workmanship Warranty and Tonal Guarantee.

To find out more, or discuss to the characteristics of the different transformers sets available for your amps, give us a call or email.