
A beginner’s guide to what makes tube amps growl, bark, and purr—from preamp tubes to output transformers and every cathode in between.
Fat, bright, warm, thick, twangy, jangly, hot, creamy—guitarists use a lot of adjectives to describe their amps' tones, and the longer you play, the more you come to understand the gist of what these terms represent sonically. But what's responsible for these foundational characteristics? What is it within a circuit that makes one amp sweetly clean while another is raw and crunchy, when both are set to the same position on the volume knob?
There are several factors under the hood that affect the aural characteristics of the signal that passes through your amp, but many of the ingredients that make various classic tube amps so different from each other are found within their gain stages. On top of that, the amps' tonal traits are further determined by how these gain stages interact with each other within the circuit as a whole—for example, how the first gain stage impacts the second, and vice-versa, as the guitar signal makes its way down the line. Even beyond the ratios of clean-to-mean and hot-to-cool that are determined by an amp's gain stages, the various configurations are also responsible for a huge part of its voice—its core tone. In most amps, the EQ stages that we often think of as shaping the tone are there just to take away specific frequency bands from the sonic foundation that has already been formed elsewhere.
Most of the amps we consider high gain use several gain stages chained together—something called "cascading gain"—to achieve a hotter signal than one or two more vintage-style gain stages are capable of on their own.
Looking beyond that core voice, gain stages are what make some amps shimmer while others scream. The Mesa/Boogie Mark IIC+, Fender Twin Reverb, Marshall JCM800 2203, Bogner Ecstasy, and Soldano SLO are all tube amps that run at approximately 100 watts, but their very different types and numbers of gain stages are responsible for making one wail, another crunch and thump, and another chime and ring. Let's dig into the basic building blocks of different gain stages found in several classic amps' preamp sections, and then we'll see how coupling them to a range of different output stages further shapes their tone and response.
Setting the Stage
"Gain stage" is the term used to describe any place within a guitar amp where gain is added to the signal—that is, where its strength is increased. The external clue to a gain stage is often found by the presence of a knob that makes the amp louder in one way or another. It might be labeled volume, gain, drive, overdrive, lead, rhythm, or something else, but if the amp gets louder (and/or more distorted) when you turn it up, chances are the potentiometer behind that knob is interacting with a gain stage.
A look at the schematic for the early-'80s Mesa/Boogie Mark IIC reveals the several gain stages, related level controls, and the tone stage in the complex preamp envisioned by company founder Randall Smith.
In traditional all-tube guitar amps, gain is achieved with tubes, so each of these gain stages we're discussing revolves around a specific part of the circuit dedicated to helping each preamp tube do its thing. In fact, there are two triodes within each of the most common preamp tubes used in modern guitar amps—12AX7s and the like—so each of those little tubes can be wired up as if it is two preamp tubes within one bottle. In other words, the most common preamp tubes can provide two gain stages. (That said, some more esoteric amp designs use an EF86, a pentode preamp tube popularized by vintage Vox AC15s and modern Matchless DC30s alike, and which has only one gain stage per tube but is capable of more gain than a 12AX7.)
Of course, a12AX7—and related tubes like the 12AT7 and 12AY7—can also be used to perform other functions within the circuit, including as part of the tremolo, reverb, or effects-loop circuit, or as a phase inverter, for example. All this means that simply counting your amp's preamp tubes and multiplying by two doesn't necessarily reveal its total number of gain stages.
As complex as it is, the single-channel circuit of the Matchless John Jorgenson Signature Model requires only one gain stage, thanks to the capabilities of its EF86 pentode preamp tube (not shown), which is mounted on the other side of the chassis behind the associated circuitry highlighted here. The EF86 is also used in the Matchless DC30.
The thing about gain stages is that their effect on any amp's overall sound is both micro and macro. That is, the accompanying circuitry (resistors, capacitors, etc.) deployed by the amp's designer plays a key role in further shaping the tonal character of each gain stage. But that sound shaping is also cumulative.
So when several gain stages are involved—and there are at least two in the preamps of most guitar amps—each begins to act upon the other to determine the sound of the guitar signal that comes out the other end. As we'll see below, the amount by which multiple gain stages increase the guitar signal as one chains into the other in a more complex multi-stage preamp also determines how much distortion can be achieved when you turn up a high-gain amp.
Voicing
The simplicity of this Komet K29's point-to-point-wired preamp makes it easy to see the methods used to voice its two gain stages, which employ both halves of a single 12AX7 preamp tube (not shown, but mounted on the underside of the chassis, beneath the two highlighted orange capacitors). Two sets of cathode-bias resistors and bypass capacitors (Box 1) help establish the core voice of each stage, while two .022µF coupling capacitors (Box 2)—one between each gain stage and the level control that follows it—further refine the frequency response.
As mentioned previously, each gain stage requires a small network of capacitors and resistors to deliver the voltage that enables the gain stage to function, and to set its operating bias. The designer's choices of the types and values of components used plays a big part in shaping the frequency range of the signal at that point in the circuit. Signal capacitors are also used between stages (so-called "coupling caps") to block unwanted voltages from straying down the line when the audio signal itself is passed along, and the type and size of these capacitors further shapes the core tone of the amplifier. Clever designers very consciously and deliberately calculate the effect that components of different values and types will have on the audio signal at each stage.
In brief, and without getting overly technical, a designer might make a particular gain stage sound cleaner or hotter by adjusting its bias through careful resistor selection, and then make it fatter or brighter by using the appropriate bypass capacitor linked in parallel to that resistor. (Interestingly, the signal doesn't actually pass through these components: They merely help govern the tube's handling of the signal.) The designer may further sculpt the amp's voicing by placing a coupling capacitor of a relatively high value between that gain stage and the next to allow a full, bassy response, or one of a lower value to enhance a higher range of frequencies. Given the types and values of components available, there are countless possible permutations and nearly endless ways to dial in an amp's tone.
The OT plays a significant part in tone shaping, and its size, design, and build quality all factor into the way it does its job.
Beyond these means of voicing a gain stage and setting its propensity to distort, the ways in which stages are chained together plays a big part in determining how the amp as a whole behaves. We might split amps into two main categories—low and high gain—but in reality there can be a lot of overlap between the two.
Low-Gain or Vintage-Style Preamps
By today's standards, the preamps in most amps of the '50s and early to mid '60s are considered low-gain. These also tend to be simple and have fewer gain stages. They generally apply just enough preamplification to get your signal to a level that the output stage can handle, since the original objective of most guitar amps was to make the guitar louder while keeping it as clean as possible, rather than to intentionally generate distortion. It's no surprise, then, that these amps lean toward a cleaner, less distorted sound when the volume control is kept within reason—maybe up to 4 or 5 on the dial, give or take. Many low-gain or vintage-style amps are also known for their juicy overdrive, of course, which is achieved by turning that volume control up higher, at which point it does start to distort and push the output stage harder. In many cases this distortion would have been considered undesirable by the designers—an anomaly caused by pushing the amp beyond its intended operational parameters—but players quickly discovered that overdriven amps produce delectably dynamic tones.
The Fender "tweed" Deluxe schematic shows the first and second gain stages, tone control, phase inverter, and output stage of one channel. Note the way the 12AX7 is used by the second gain stage and phase inverter.
Good examples of this sort of amp are the Fender "tweed" Deluxe and the normal channel of a Vox AC30—as well as the many amps they inspired. Each has just a single gain stage in the preamp, although the tweed Deluxe also has another gain stage—often called a "driver" stage—right in front of the phase inverter, which is the gateway to the output stage.
Others, such as Fender's "blackface" Deluxe Reverb, Twin Reverb, and similar models, have multiple tone controls (treble, bass, and sometimes middle) in a more complex EQ circuit sandwiched between two tube gain stages. This doesn't always make the amps a lot "hotter," though, because that second stage is necessary to recover some signal level that's lost in the more complex tone network (which, of course, also allows more fine-tuning of the amp's frequency response). The tweed Deluxe and its ilk, on the other hand, have only a simple tone control that acts as a "treble bleed," much as the tone control on a guitar, to pass some of the high frequencies to ground, rather than having the entire signal pass through it and lose gain in the process.
Others still, such as larger tweed amps, the Vox "top boost" channel, and the Marshall plexi-style preamp, have a first gain stage followed by another tube that drives the tone network that follows it—something called a "cathode follower." In the most basic sense, the results are somewhat similar in all of these, in that the ratio of clean to overdrive in these low-gain preamp types correlates fairly directly to their volume levels. Yet each of these amps shapes your guitar signal somewhat differently, leading to variations in tone, distortion, and playing feel. All are technically low-gain circuits, but some players will express distinct preferences for one over the other according to how they perform.
High-Gain Preamps
This diagram illustrates the cascading gain stages, cathode-follower stage, tone stage, and phase inverter of an early-'80s Marshall JCM800 2204 in lead mode.
Consider the sound of the lead channel in modern channel-switching amps or single-channel amps intended purely for rock overdrive, and what you're hearing is a high-gain preamp. Although we refer to these as modern, this topology really roared into existence in its popular form in the late '60s, when Randall Smith introduced his first Mesa/Boogie amps. Shortly thereafter, others also began modifying existing amps' low-gain preamps to become high gain.
As we've touched on already, a single gain stage can be designed to squeeze the maximum amount of gain from that preamp tube, but most of the amps we consider high gain use several gain stages chained together—something called "cascading gain"—to achieve a hotter signal than one or two more vintage-style gain stages are capable of on their own. In amps of this type, the saturated overdrive sound we hear is typically produced by pushing early gain stages to very high levels, often chaining one into the other to continually drive the gain higher and enable desired levels of distortion, and then reining in the signal at the end of the line to create the desired final output level.
There's a broad range of high-gain designs on the market, and different makers' amps often do things in quite different ways. It's also worth noting that they achieve a pretty wide range of gain levels within what we broadly call "high gain." For example, today's metal player might not consider a late-'70s Marshall 2204 high-gain at all, whereas it would have sounded extremely hot to the average rocker of its era.
Familiar names that typify the high-gain genre are Bogner, Soldano, Diezel, Fryette, EVH, ENGL, Fuchs, and, of course, good old Marshall and Mesa/Boogie—plus far, far more than we can list here. Most follow some evolution of circuitry that began with the original Mesa/Boogie designs, which chain together several gain stages. By increasing the gain incrementally from stage to stage (usually with controls labeled drive, gain, lead, or even just volume placed between them to govern how much signal from the previous stage is passed along to the next as you ramp up the signal all along the chain), designers can both conjure much higher levels of gain than a one- or two-stage preamp and still provide the player with the ability to dial in anything from the minimum to the maximum of that preamp's capabilities.
Even a relatively minor change of tubes or components or values or topologies within one little stage somewhere between input and output might change an amp's tone.
Earlier renditions of cascading-gain amps, such as the Marshall 2204 and its ilk, only chained two gain stages into each other, with a master volume control further down the signal path to govern the overall volume. Modern high-gain amps, on the other hand, might have four or more gain stages.
Channel Switchers
Most modern high-gain amps also offer two or more footswitchable channels. The clean or rhythm channels are often configured like traditional one- or two-stage vintage preamps. If there's a channel between the low-gain rhythm and high-gain lead channels, it's usually configured to produce anything from crunch to a more old-school lead, using a couple of gain stages.
In these amps, a stomp of the footswitch merely selects which of the multiple preamp channels is routed to the output stage, which itself is not reconfigured in any way. (A few more elaborate designs do offer some switchable changes in the back end, too. Fryette's Sig:X and Mesa/Boogie's Mark Five amps come to mind, but this is still a rare feature.) Most so-called channel switchers simply incorporate different types of preamp stages that exist in parallel to each other, with only one being active at any time.
On the other hand, some channel switchers with high-gain possibilities introduce their lead modes by enabling an extra gain stage or two after the initial stages that provide the clean/rhythm mode. The original Mesa/Boogie designs were like this, with the guitar signal running through both the clean and lead circuits when switched to lead mode. Similarly, Dumble's legendary Overdrive Special—and the many amps inspired by it—add a two-stage overdrive circuit to the foundation that you're already running through for your rhythm tone when you stomp on the lead footswitch.
Another big distinguisher between multi-channel amps is whether the individual channels have their own EQ stages or share a stage. The former allows the player to tailor tone settings to suit the individual channel, but is obviously more complicated to build and requires squeezing more into the circuit. The latter requires finding a compromise in tone settings that works for both the rhythm and lead channels (and possibly a crunch channel)—although in most well-designed amps this isn't all that difficult to achieve.
Master Volume vs. No Master Volume
This Divided by 13 CCC 9/15 amp uses a post-phase-inverter master volume (PPIMV, highlighted here), with shielded leads running to and from the circuit junction just beyond the phase inverter.
Almost all high-gain amplifiers have a master volume control, which is necessary to achieve the desired overdrive/distortion level at a manageable overall volume. In such cases, the first volume, gain, or drive control (the name can vary) sets the gain of the first preamp stage, while the master volume generally follows any and all other gain stages to govern how much signal is passed on to the output stage.
A master volume can be placed toward the back end of the preamp stage, or in an early part of the output stage, or just about anywhere in between, but will behave somewhat differently in different locations. Many modern high-gain amps with multiple gain stages have corresponding level controls within each preamp channel, in addition to a master control in the output stage to govern overall volume. If your amp has a lead channel with controls labeled gain, lead level, and master, for example, this is most likely what you are seeing: one knob to set initial preamp gain, another to rein it in following a further gain stage, and a final control to set the overall volume level of the amp (which might also determine the final volume level of any clean/rhythm channel that the amp includes).
A late-stage master volume control (also sometimes called a level control, or just volume, if the first-stage control is labeled something like gain or drive) is often configured as a "post-phase-inverter master volume," which you'll often see shortened to PPIMV, so-named because it comes after the phase-inverter but before the output tubes, placing it well into the output stage. Such masters are praised by many players for their "transparency"—the way they preserve the fundamental tone and gain settings of the rest of the amp and allow you to achieve your desired sound at lower volumes, rather than changing the core tone when the master is turned down.
In truth, almost any means of lowering overall amp volume will change its sound slightly. The mere act of reducing decibels makes things sound somewhat different to the human ear. But in many cases, reducing the signal level that hits the output tubes also alters tones in other ways, if only slightly. Even so, several designers have gotten pretty close to perfecting the transparent master volume, and this knob performs superbly in many amps.
That said, the master volumes used in highly acclaimed Marshall 2203 and 2204 amps of the late '70s used potentiometers placed further up the signal chain, right after the tone stack and beforethe phase inverter—yet few players complain about these amps' legendary overdrive tones.
No Master Volume Control
Following the circuit of Marshall's 2204 master-volume amps of the late '70s, this MGL20 has a preamp gain control for its first gain stage (highlighted at left), and a master control that immediately follows its tone stage (right) in the signal chain, meaning it comes beforethe phase inverter.
In the early days of the "boutique" amp craze, and somewhat as a backlash to the high-gain, channel-switching monsters of the '80s and early '90s, there was a lot of buzz about non-master-volume amps—amps built more to vintage-inspired standards and designs.
If your amp has no master volume and just a single volume control (or one volume control per channel), it's probably a low-gain preamp. That doesn't mean you can't push it into overdrive, but you will usually need to crank the volume up to get there—and many players may still want an overdrive or distortion pedal out front for more saturated lead tones. However, not all non-master-volume amps are low gain. The highly prized Trainwreck amps made by the late Ken Fischer (and now being made under license), as well as models by builders such as Komet and Dr. Z—some of which were also co-designed by Fischer—have relatively high-gain preamps. Either way, if your amp lacks a master volume and you can only get your favorite tones at impractical volumes, you can purchase an output-attenuator unit to insert in the signal path between your amp's output and speaker(s). This lets you turn up the amp to achieve the desired level of dirt, then rein in the volume via the attenuator's level control.
Low-Gain with Master
These days, many amps with low-gain preamps also have a master volume. This configuration doesn't usually yield true high-gain tones, but it can frequently allow decent crunch or even vintage-level lead tones by turning up the initial volume and turning down the master volume.
The Output Stage
An amp's output stage comprises everything from the input side of its phase inverter to the jack on the back of the amp that sends the signal to the speakers, including the output tubes and output transformer in between, plus a bunch of capacitors and resistors connecting it all.
The output stage takes the relatively low-level electrical signal that the preamp has already increased in voltage and increases the voltage further, ultimately converting it to a high-wattage, low-impedance signal that will drive a speaker. The output stage begins with the phase inverter, which includes yet another preamp tube that is configured with a network of resistors and capacitors to split the audio signal into two strands, while flipping one strand to the reverse of the other's phase in order to pass along two mirror-image signals to the two sides of the output stage for final amplification.
The split, inverted signal is then passed to two output tubes (or two parallel-wired pairs in larger amps), which act in a "push-pull" configuration—one tube "pushing" one side of the split signal while the other tube "pulls" its reverse-phase partner—to further increase the signal's strength and send it along to the output transformer. The output transformer then converts the signal to one that will power a speaker. (Note that small "single-ended" amps with just one output tube, such as the Fender Champ or Vox AC4, don't work in this push-pull manner, and therefore don't require a phase inverter.)
Power and Distortion Capabilities
This MGL AmpWorks Lead Master 50's output transformer is the larger of the silver transformers, at the center of the row of three transformers behind the row of tubes. To its right is the power transformer, and to its left is the choke.
It's also important to know that the output stage is where an amp's overall power capability is determined: The combination of the type (and number) of output tubes and output transformer used are what make it a 15-watt amp or a 100-watt amp. A pair of 6V6s or EL84s and a relatively small output transformer deliver the former, for example, while four 6L6s or EL34s and a large transformer yield the latter. Any type of preamp stage we've discussed here, high gain or low, can essentially be partnered with any type of output stage.
In addition to determining output level, the output stage plays a big part in shaping the character and degree of the distortion induced when the amp is driven hard. Although in most amps the majority of distortion is generated in the preamp, this signal will drive smaller, lower-powered output stages harder than it will larger, higher-powered stages, thereby inducing more output-stage distortion in smaller amps, which can dramatically change the character of your overdrive sound in some cases.
Biasing Methods
Output-tube biasing might seem a rather esoteric and technical subject, but it's worth knowing a little about because the method by which any given amp is biased can affect its sound and performance. Further, knowing how an amp is biased should tell you a little something about the nature of its playing feel and harmonic content.
All tubes need to be biased—that is, have some control method applied to set their operating level at idle (much the way a car's carburetor is adjusted to set its idle)—but it is most significant with regard to output tubes. Bias is a very involved subject, but you mainly need to know that most amps' output tubes are biased in one of two main ways—by connecting their cathodes to ground via a large resistor of a value that determines this bias, or by applying a low negative voltage to their grids, as supplied by a small network of components connected to a tap on the power transformer. The former method is called "cathode bias," and the latter "fixed bias"—rather confusingly, perhaps, because the bias level on most fixed-biased amps made from the early '60s onward can actually be adjusted, whereas the bias level on cathode-biased amps is preset and cannot be adjusted (not without physically changing the bias resistor, at least).
Bias methods are significant because they help determine an amp's character and efficiency. Fixed-bias amps make somewhat more efficient use of their output tubes, in most cases, and provide a means of squeezing the maximum output wattage from any given design, while also generally sounding a little tighter and firmer, in the low-end in particular. Fender's Twin, Deluxe Reverb, and Bassman, and Marshall's JTM45 and plexi amps are classic examples of fixed-bias amps. Cathode-biased amps, on the other hand, tend to be less efficient, wattage-wise, while being characterized by a somewhat greater level of harmonic overtones when they begin to distort, along with what might be perceived as a softer bass response—and sometimes a slightly more tactile playing feel, too. Classic cathode-biased amps include the Fender tweed Deluxe, Vox AC15 and AC30, Matchless DC30, and Carr Mercury.
Output Transformers
In the vast majority of tube guitar amps, the output transformer (OT) is the largest component in the signal chain. It converts the high-impedance signal from the output tubes to a high-wattage, low-impedance signal. The OT is usually the second largest transformer hanging from the chassis' underside—the largest being the power transformer. Given that this component transforms the electrical signal from the output tubes to one that the speaker can pump through the air and into your ears, the OT plays a significant part in tone shaping, and its size, design, and build quality all factor into the way it does its job.
Roughly speaking, the bigger the OT relative to the output tubes, the bolder the sound and firmer the bass response. OT size also tends to equate to maximum wattage capabilities, although the OT can only translate what the output tubes provide. There are many other design parameters involved, of course, and these are just basic rules of thumb.
None of this means, however, that bigger is always better. An OT needs to be appropriately sized for the tubes that feed it, and appropriate to the designer's overall goals, too. For example, many smaller or mid-sized amps owe some of their juicy, succulent overdrive character to the fact that their output tubes are saturating a relatively small OT. Install a bigger, supposedly "higher quality" OT, and they might sound colder and less characterful.
The Tip of the Iceberg
If you want to learn more about the minutiae of how amplifier gain stages work, there are options out there for a tech deep-dive. But it should be easy enough already to see what a major mix-and-match puzzle any guitar amp is, and how much even a relatively minor change of tubes or components or values or topologies within one little stage somewhere between input and output might change its tone.
In the end, you really don't have to know how every little link in the signal chain functions to find the amp that will work best for you. But a good grounding in their basic operations—and more importantly, how different elements equate to different sound and feel—should help you narrow the search for the amp(s) that will best help you achieve your musical goals.
A Word About Tone Stages
Like many of its "blackface" kin, the Fender Super Reverb has a second gain stage that's essentially a gain make-up stage. The highlighted areas in this photo of a Super circuit show (Box 1) the first channel's first gain stage, gain make-up stage, and related circuitry, and (Box 2) the inputs and volume, treble, and bass controls related to those two gain stages.
Tone stages (aka EQ stages) are also part of the preamp, but are generally considered apart from gain stages per se, although some types of tone stages do contain, employ, or rely upon gain stages provided by preamp tubes.
In smaller or more basic amps, like the archetypal Fender "tweed" Deluxe, a single tone control might not be a stage unto itself at all, but rather a simple treble-bleed network formed by a potentiometer and a capacitor or two that determine how much high-frequency content is tapped out of the signal before it exits the preamp. More complex EQ stages have separate bass and treble controls, and many add a midrange control, too, frequently using a preamp tube either to drive those controls (to avoid signal loss) or as a gain make-up stage following the tone controls to get the signal back up to where it needs to be prior to hitting the output stage.
Although most tone stages' controls feature similar names, they can execute their functions via very different electrical means—and they can have vastly different levels of interactivity and frequency controllability.
Other than the one-knob tone control found on tweed Deluxe-style amps, there are two common tone-stage topologies. In one camp are those found on the Fender tweed Bassman, Marshall JTM45 and plexi amps, the Vox AC30's "top boost" channel, and similar models. In the other are those found in "blackface" and "silverface" Fenders like the Deluxe Reverb and Twin Reverb. The former group uses an entire preamp tube positioned before the tone controls as a driver and cathode-follower (that is, the signal comes out of the tube's cathode, rather than its anode). The latter places the tone controls between the channel's first gain stage and a second traditional gain stage (called a gain make-up stage) that replaces the gain lost by the signal while travelling through the controls and related circuitry. In addition to having controls that interact with each other slightly differently, each tone-stage topology also imparts a slightly different playing feel to the amp, best defined as a crisp and snappy response in the blackface/silverface tone stack, and a tactile, somewhat creamier, touchy-feely response in the tweed/Marshall cathode-follower topology.
[Updated 8/23/21]
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At home in the shop at Gibson USA, where DeCola is R&D manager and master luthier.
The respected builder and R&D manager has worked for the stars—Eddie Van Halen, Paul McCartney, and others—while keeping his feet on the ground, blending invention, innovation, and common-sense design.
As a teenager, DeCola fell in love with surfing, but growing up in Indiana … no ocean. So, skateboarding became his passion. When a surf park called Big Surf—replete with rideable waves—opened up near his sister, who he was visiting during spring break at Arizona State University, she treated him to a day at the man-made sea.
Jim DeCola paid for his first guitar with his nose.
“When the first wave came, it scooped us all up, and I was tumbling under and something hit me bad,” he recounts. “So, I’m in a daze, and my sister runs up to me and says, ‘Oh my god, you have a bloody nose!’” When DeCola looked in the bathroom mirror, his nose was broken and the skin was split. The surf park’s medic sent him to a hospital. “Whatever the bill is, give it to us and we’ll double it,” DeCola recalls being told. “Just please don’t sue.” When a check for $880 arrived, his mother suggested he use it to buy the electric guitar he was pining for. “I ended up with a Gibson SG, because George Harrison had one, but they didn’t have a cherry red one, so mine was ebony.” He also got a Roland Cube practice amp because it had a master volume. “I still have both, and it’s still a great little amp and a great guitar. And that,” he says, “set me on my course.”
It’s been an epic journey in guitar creation: from his apprenticeship at a Lansing, Illinois, shop—which led to a dramatic and well-chronicled bridge fix for Randy Rhoads—to his years with Peavey, Fender, and now Gibson, where he is R&D manager and master luthier. DeCola blanches a bit at the master luthier title, observing that he’d prefer, simply, “guitar guy,” but that’s like calling a tiger a cat. DeCola is an apex builder. Instruments he designed are world-renowned and he’s collaborated with an enviable list of greats that includes Eddie Van Halen, Paul McCartney, Slash, Adrian Vandenberg, Rudy Sarzo, Neil Schon, and Randy Jackson.
Jim DeCola at the Gibson USA offices in Nashville. He spearheaded the company’s current two-pronged product orientation, with original and modern instrument lines.
Photo by Ted Drozdowski
In the Beginning…
DeCola’s family was musical. His dad played many instruments but trumpet was his main squeeze, and his older brother and sister exposed Jim to the Beatles, Stones, Hendrix, Cream, and other deities of the ’60s guitar-rock canon. Thus fueled, at 15, in his second year of wood shop, he decided to build a guitar. Inspired by a photo of Scorpions’ Matthias Jabs, he settled on an Explorer body shape. A friend who already played guitar detailed where the bridge needed to go and what parts were required, and DeCola reverse engineered from there. He even cut the pickguard from a sheet of gray smoke Mirrorplex. But despite two years of electronics classes, he opted to bring his creation to the Music Lab, that guitar shop in Lansing, where he was taking lessons, for the wiring.
“The guy who did repairs wired it up for me, and when it was ready he called and said, ‘Hey, I want to talk with you when you come in,’ ” DeCola recounts. “He asked me to apprentice with him. It was learn while you earn, and while I did learn some stuff from him, really, I was wet sanding guitars and doing that kind of grunt work.” DeCola was at Music Lab part-time for 18 months, and graduated from high school just as the tech left. The owners of the store asked Jim to take over, and, as Suetonius told Caesar, the die was cast.
In January ’82, a caller made DeCola think he was being pranked—until he became convinced it really was Randy Rhoads and Rudy Sarzo’s tech Pete Morton. They explained that Bruce Bolen, then at Chicago Musical Instruments, had suggested him to fix Rhoads guitar in time for the night’s Ozzy Osbourne performance. DeCola grabbed his tools and drove through the snow for 50 miles to the Rosemont Horizon arena, where Rhoads was having trouble keeping the vibrato bridge on his polka-dot Sandoval custom V in tune. After a quick round of introductions, DeCola took apart the vibrato bridge and used a technique inspired by G&L guitars, deleting two of its bridge’s four screws and cutting a pivot with a V-file to countersink the bridge plate. Next, he was treated to a soundcheck of “Mr. Crowley” by Rhoads, Sarzo, and drummer Tommy Aldridge. As the opening act played, Rhoads asked DeCola to make the vibrato “a little slinkier,” and he completed the mod just before Ozzy’s downbeat. DeCola—still in his teens—was standing just off to the side when the iconic photo of Ozzy carrying Rhoads that appeared on the cover of the 1987-released Tributealbum was taken.
Six years later, DeCola received offers from Kahler and Peavey, and he opted to relocate to Meridian, Mississippi, to work with Hartley Peavey as his R&D tech. “I learned a lot,” he reflects. “Hartley was a great mentor. At any time, I’d have a stack of books and magazines, or just single pages ripped from magazines, a foot high on my desk, and he’d expect me to read and give him a report on everything,” says DeCola. “Sometimes it was related to guitars, amps, and effects; sometimes it might be antique radios.” After a few years, DeCola was promoted to supervisor of guitar engineering and began designing instruments. DeCola minted some of Peavey’s most lauded guitars, including the Tele-like Generation, with dual humbuckers, a mahogany body and neck, and a 5-way switch. That guitar gave the company a toehold in the country music market, but was also embraced by Steve Cropper and Dave Edmunds.
“We looked at each other and said, ‘The decade of the “superstrat” is over.’”
Every Best Les Paul Sound
Another pivotal experience during his years at Peavey happened at a summer NAMM show in Chicago’s McCormick Place, when a celestial Les Paul tone suddenly emerged from the exhibition hall’s PA system. “It was ‘Sweet Child O’ Mine’ by Guns N’ Roses,” says DeCola, “and we’re looking up thinking, ‘Who the hell is this?’ It was every best Les Paul sound wrapped up into one. We looked at each other and said, ‘The decade of the “superstrat” is over.’ And it really was.”
That inspired DeCola to create the Les Paul-Tele-style hybrid Peavey Odyssey. He also worked with Adrian Vandenberg on set-neck and neck-through versions of the Dutch guitarist’s signature models, and a host of other artists—including Eddie Van Halen. Peavey’s artist relations head heard that Van Halen had a falling out with Ernie Ball Music Man and sensed opportunity. DeCola quickly made a prototype inspired by Eddie’s EBMM signature model and took it to a gig in Florida, where the band was kicking off the Balance tour. “Eddie rehearsed with it and said, ‘Okay, now I know you can do it; let’s come up with a design.’”
During the development process, DeCola learned that Eddie’s son Wolfgang had a birthday coming. So, as a gift for Wolfie, he decided to make a 3/4-size example of his signature concept for Eddie. Mid-build, Eddie made a surprise visit to Meridian. DeCola invited EVH into his office and showed him Wolfie’s guitar.
“I thought this would be the direction we’d use for your new model,” DeCola explained. “He said, ‘Yeah, I love it! Just make it full size, then.’ And for the headstock, Eddie had done some napkin drawings in the hotel that were like Flying V’s, but smaller.” That wouldn’t work, thanks to the U.S. Patent Office. More ideas were exchanged. DeCola was coincidentally working on a new build for himself at the time, with a three-to-a-side headstock. He painted that headstock black, and then sanded a scoop in its tip. And that was it. Eddie was happy. DeCola wanted to get a prototype into Van Halen’s hands as quickly as possible, so when he found out the virtuoso was leaving Meridian the next day after lunch, he worked through the night.
“When he showed up the next morning at 11 a.m., I was just tuning it up,” DeCola recalls. “It was raw wood, but he played it and said, ‘That’s it.’” Thus, the Peavey EVH Wolfgang was born. “After that, the engineering took longer than making the guitar, because I had to do the blueprints and totally spec out everything,” DeCola adds.
Another important encounter he had in Meridian was with the blues historian and record collector Gayle Dean Wardlow, noted for, among other things, finding the death certificate of Robert Johnson. After they met, DeCola started going to Wardlow’s home weekly to talk about the roots of the genre he’d begun studying as a young player, listen to rare old 78s, and absorb the techniques preserved in their shellac. That study paid off. Hearing DeCola play metal-bodied resonator guitar is a high-order experience, although he also sounds terrific rocking the hell out on a Les Paul. DeCola is humble about his playing, but, really, he doesn’t need to be. “It’s a great release, and great therapy,” he says.
DeCola’s tenure at Peavey ran its course. “I was making P-90 and 12-string versions of existing guitars, a 12-string baritone … and they were turning my operation into a custom shop, which I didn’t want to do, because that’s just low-volume manufacturing. I wanted to stick with designing new stuff,” he says. “I wanted a change. It was five years with a lot of pressure. I wasn’t getting credit for designing and building Eddie Van Halen’s guitars. So, I went to Fender in Nashville, who had what they called the Custom Shop East at the time.”
“Musicians and skaters have the same kind of soul, the same mindset,” DeCola says. “It is something you can do by yourself, as a form of expression, but when you’ve got your crew and you’re skating, it’s like being with your band.”
Photo courtesy of Jim DeCola
“I came up with the idea of teaching people how to use things that every guitar player is going to have around the house for tools—coins or picks—and MacGyver their instruments.”
On to Gibson
There, he worked with Bruce Bolen and pickup guru Tim Shaw. But after Bolen retired in 2011 and Fender decided to close that Nashville location, DeCola found out about openings at Gibson and applied. In June, he was hired as master luthier.
“Gibson’s been a great ride,” DeCola attests. Although it hasn’t always been easy. When DeCola came onboard, the notoriously controlling, sometimes-volatile Henry Juszkiewicz was CEO. “It was fine for me, because Henry respected me, but it was an environment where I felt I had to be measured in my responses,” he says. There were also notorious design gaffes, like “robot tuners” and the dreadful Firebird X—both pet projects of Juszkiewicz that almost literally no one else, especially customers, desired.
“I got blamed for some of that stuff, but I was just the messenger,” DeCola says. But as James Curleigh and, now, Cesar Gueikian took over Gibson’s leadership, DeCola had an opportunity to proactively get his thoughts on the direction for the company’s products before more receptive CEOs.
“I made a bullet list and at one point had maybe 40 things on there, like going back to a thin binding on certain models and changing features,” he relates. “But my main message was, ‘Give the people what they want; we’re not here to dictate what people want.’” Many of DeCola’s ideas were manifested in the roster of guitars at the Gibson display at NAMM 2019—instruments that honored and built upon the company’s legacy. DeCola also had the idea of splitting Gibson’s model line into original and modern categories. “My concept was, we have the original models, which we’re determined to improve, and the modern line where we could have locking tuners, push-pull pots, and blueberry burst finishes—features that aren’t rooted in the golden years of the ’50s.”
Gueikian embraced that practice for Gibson USA and the Custom Shop, and expanded it to the acoustic Custom Shop in Bozeman, Montana, and to the Mesa/Boogie amp line. But DeCola was already on the case with amplification. Before Curleigh stepped down, he’d asked DeCola to look at Gibson’s amp line, and, again, DeCola looked back andforward at once. Inspired by his personal collection of vintage Gibson amps, he mapped out a new product line for 10-, 20-, and 40-watters. “I based my thinking off the greatest hits of those classic amps, and focused on the Falcon, because I have a ’62 Falcon, and when I looked into its history, the revelation was that it was the first amp with both reverb and tremolo,” he says. “So, I thought that would be a cool amp to make.” Then Gibson bought Mesa/Boogie under Gueikian’s stewardship, and the project went to that company’s Randall Smith, who created a stellar original design. Gibson unveiled the power-switching Falcon 5 (which won PG’s coveted Premier Gear Award) and Falcon 20 in January 2024.
DeCola is skilled in every aspect of guitar building, including working in the spray shop, where he is seen here training the gun on a model year 2024 blueberry burst Les Paul Studio.
Photo courtesy of Gibson
Mr. Fix-It
While the profile of most people in the guitar industry went down during the pandemic, DeCola’s went up thanks to a series of how-to videos he made for Gibson’s YouTube channel. They cover such topics as how to adjust action and pickup height, and how to do a proper setup. “I wanted to do something for the guitar community when things were shut down, so I came up with the idea of teaching people how to use things that every guitar player is going to have around the house for tools—coins or picks—and MacGyver their instruments,” he says. These videos have hundreds of thousands of views, and have given him a kind of celebrity status that’s rare among luthiers.
When asked what makes a great guitar, including the signature models he’s worked on at Gibson for Paul McCartney, Slash, and others, DeCola talks about achieving a commonsense, holistic balance of design, materials, and craftsmanship. He adds that there is no shortage of fine instruments now available, and that, moving ahead, he sees the kind of balance between tradition and invention that he has promoted at Gibson remaining its norm. “There are a lot of boutique builders and trends like 7- and 8-string guitars, fanned frets, and different scale lengths today,” he notes. “Some of it can be cyclical. There was a period in the ’80s and ’90s, for example, when a lot of people were adopting 7-strings, and now I see a lot of them again.
“Gibson was built on innovation,” he continues. “Orville Gibson, our founder, got his first patent creating a mandolin built completely different than other mandolins. Prior to that, they were typically gourd instruments, but he applied the carved back and top method from the violin and cello. And with the jazz-box electric guitars, there were so many Gibson innovations, like the adjustable neck and bridge, the humbucking pickup…. But because we’re a legacy company, we have to tread a bit lighter on some of the innovation, which our previous leadership was too forward on, with features the market wasn’t ready for. But in defense of that, I’ll go back to our heritage instruments. The Flying V and Explorer were all designed out of the space race, but initially commercial flops—too ahead of their time. So that’s why I wanted to split the model line—so we have the latitude to come up with some new things, but can still honor what’s expected of Gibson. Right now, we’re looking at some innovation in electronics and other features we will be bringing to the market.”
Now in his early 60s, DeCola is also still working on his skateboard moves. He tries to get to Nashville’s municipal Two Rivers Skatepark and Rocketown once a week. There, he’s found a coterie of fellow veteran skaters—many of whom are also in the music business, as players, producers, and engineers. “I’d say musicians and skaters have the same kind of soul, the same mindset,” he says. “It is something you can do by yourself, as a form of expression, but when you’ve got your crew and you’re skating, it’s like being with your band. It’s even more fun, and it inspires you. It can make you better.”DeCola performs a neck adjustment on an ES-335.
Photo courtesy of Gibson
Some of these are deep cuts—get ready for some instrumental bonus tracks and Van Halen III mentions—and some are among the biggest radio hits of their time. Just because their hits, though, doesn’t mean we don’t have more to add to the conversation.
Naturally, every recording Eddie Van Halen ever played on has been pored over by legions of guitar players of all styles. It might seem funny, then, to consider EVH solos that might require more attention. But your 100 Guitarists hosts have their picks of solos that they feel merit a little discussion. Some of these are deep cuts—get ready for some instrumental bonus tracks and Van Halen III mentions—and some are among the biggest radio hits of their time. Just because their hits, though, doesn’t mean we don’t have more to add to the conversation.
We can’t cover everything EVH—Jason has already tried while producing the Runnin’ With the Dweezil podcast. But we cover as much as we can in our longest episode yet. And in the second installment of our current listening segment, we’re talking about new-ish music from Oz Noy and Bill Orcutt.
John Doe and Billy Zoom keep things spare and powerful, with two basses and a single guitar–and 47 years of shared musical history–between them, as founding members of this historic American band.
There are plenty of mighty American rock bands, but relatively few have had as profound an impact on the international musical landscape as X. Along with other select members of punk’s original Class of 1977, including Patti Smith, Richard Hell, and Talking Heads, the Los Angeles-based outfit proved that rock ’n’ roll could be stripped to its bones and still be as literate and allusive as the best work of the songwriters who emerged during the previous decade and were swept up in the corporate-rock tidal wave that punk rebelled against. X’s first three albums–Los Angles, Wild Gift, and Under the Big Black Sun-were a beautiful and provocative foundation, and rocked like Mt. Rushmore.
Last year, X released a new album, Smoke & Fiction, and, after declaring it would be their last, embarked on what was billed as a goodbye tour, seemingly putting a bow on 47 years of their creative journey. But when PG caught up with X at Memphis’s Minglewood Hall in late fall, vocalist and bassist John Doe let us in on a secret: They are going to continue playing select dates and the occasional mini-tour, and will be part of the Sick New World festival in Las Vegas in April 12.
Not-so-secret is that they still rock like Mt. Rushmore, and that the work of all four of the founders–bassist, singer, and songwriter Doe, vocalist and songwriter Exene Cervenka, guitarist Billy Zoom, and drummer D.J. Bonebreak–remains inspired.
Onstage at Minglewood Hall, Doe talked a bit about his lead role in the film-festival-award-winning 2022 remake of the film noir classic D.O.A. But most important, he and Zoom let us in on their minimalist sonic secrets.Brought to you by D’Addario.
Gretsch A Sketch
Since X’s earliest days, Billy Zoom has played Gretsches. In the beginning, it was a Silver Jet, but in recent years he’s preferred the hollowbody G6122T-59 Vintage Select Chet Atkins Country Gentleman. This example roars a little more thanks to the Kent Armstrong P-90 in the neck and a Seymour Duncan DeArmond-style pickup in the bridge. Zoom, who is an electronics wiz, also did some custom wiring and has locking tuners on the guitar.
More DeArmond
Zoom’s sole effect is this vintage DeArmond 602 volume pedal. It helps him reign in the feedback that occasionally comes soaring in, since he stations himself right in front of his amp during shows.
It's a Zoom!
Zoom’s experience with electronics began as a kid, when he began building items from the famed Heath Kit series and made his own CB radio. And since he’s a guitarist, building amps seemed inevitable. This 1x12 was crafted at the request of G&L Guitars, but never came to market. It is switchable between 10 and 30 watts and sports a single Celestion Vintage 30.
Tube Time!
The tube array includes two EL84, 12AX7s in the preamp stage, and a single 12AT7. The rightmost input is for a reverb/tremolo footswitch.
Set the Controls for the Heart of the Big Black Sun
Besides 3-band EQ, reverb, and tremolo, Zoom’s custom wiring allows for a mid-boost that pumps up to 14 dB. Not content with 11, it starts there and goes to 20.
Baby Blue
This amp is also a Zoom creation, with just a tone and volume control (the latter with a low boost). It also relies on 12AX7s and EL84s.
Big Bottom
Here is John Doe’s rig in full: Ampeg and Fender basses, with his simple stack between them. The red head atop his cabs is a rare bird: an Amber Light Walter Woods from the 1970s. These amps are legendary among bass players for their full tone, and especially good for upright bass and eccentric instruments like Doe’s scroll-head Ampeg. “I think they were the first small, solid-state bass amps ever,” Doe offers. They have channels designated for electric and upright basses (Doe says he uses the upright channel, for a mid-dier tone), plus volume, treble, bass, and master volume controls. One of the switches puts the signal out of phase, but he’s not sure what the others do. Then, there’s a Genzler cab with two 12" speakers and four horns, and an Ampeg 4x10.
Scared Scroll
Here’s the headstock of that Ampeg scroll bass, an artifact of the ’60s with a microphone pickup. Doe seems to have a bit of a love/hate relationship with this instrument, which has open tuners and through-body f-style holes on its right and left sides. “The interesting thing,” he says, “is that you cannot have any treble on the pickup. If you do, it sounds like shit. With a pick, you can sort of get away with it.” So he mostly rolls off all the treble to shake the earth.
Jazz Bass II
This is the second Fender Jazz Bass that Doe has owned. He bought his first from a friend in Baltimore for $150, and used it to write and record most of X’s early albums. That one no longer leaves home. But this touring instrument came from the Guitar Castle in Salem, Oregon, and was painted to recreate the vintage vibe of Doe’s historic bass.