Today it's obvious that a guitar amp has a gain knob to set "the amount of distortion." Many amps have a dedicated drive channel; step on it and deep distortion rises. Distortion has become a function the amp prepares in advance.
But it wasn't always so. For a long time distortion wasn't something the amp prepared — it was something the player added afterward. This piece is about that shift: distortion going from "something you add" to "something you design," and then to "something whose place of design you choose."
The era when it was a byproduct
Early guitar amps weren't built to distort.
A tube amp was a device for making a big sound. Distortion "resulted" when you raised the volume and the power stage or output transformer saturated. Not the designer's intended goal, but a byproduct that happened to appear when you ran it to the limit. But the players of the 1950s–60s discovered that byproduct and began using it actively. The natural distortion from cranking an amp full up is still an object of longing.
The problem was that this distortion came as a set with the condition of "high volume." If you wanted to distort, you had to make a deafening sound. So devices for getting distortion at lower volume were born. Place a fuzz or overdrive pedal in front to crush the signal going into the amp first. Or, hold the volume down with a rear-stage master while pushing the front stage.
In this era, what decided the amount and character of distortion was not the amp's design but the player's touch. The amp provided a foundation, and how to add distortion to it was the player's domain. Distortion was added with an "external device" — the pedal.
Putting distortion at the center of the product
Eventually, amps appeared that made distortion itself the object of design.
A major turning point was the idea of cascading multiple gain stages in series. A tube that only distorts lightly in one stage is passed through many stages in series, distorting a little at each. The Mesa/Boogie Mark series was one amp that early on gave form to this "assemble distortion as a circuit" idea. It builds distortion inside the preamp and separates it from the power stage's volume. Deep, smooth distortion became available without a deafening sound.
From the late 1980s into the '90s, this flow accelerated. The Soldano SLO, Marshall's master-volume amps and the 6100, Mesa's Rectifier — the current called "high gain" stands on this idea. Distortion became not something the player adds but something the amp designs and builds in, in advance. A dedicated drive channel, a footswitch, a Gain knob. Distortion was placed at the center of the product.
What's now in question is no longer the "amount" of distortion. At which stage, in what order, at what density do you distort? Even distortion of the same depth — distorting at the front and lightly tidying, versus distorting a little across many stages — has completely different grain, separation, and return-feel. Distortion became a matter of structure, not amount.
The place of design moves further out
The idea of designing distortion didn't stay inside the amp.
Once depth of distortion was broadly available, what mattered next was "what you put into the amp." Place, in front of a high-gain amp, a booster that deliberately trims the low-mids and lifts the level a touch. Then, at the same amp settings, the distortion changes to something astonishingly tight and clearly outlined. Rather than increasing the amount of distortion, you decide the skeleton of the output by crafting the signal before distorting.
In much of modern high gain, the character of the sound is already decided before the amp distorts. What to cut, what to lift before sending it in — the design point of distortion has drifted outward: from the power stage to the preamp, from the preamp to the entrance, and then to ahead of the amp.
This is the same move CSL keeps writing about. The control layer that decides the sound keeps moving from inside the amp to outside. Distortion is no exception. Distortion went from "something you add" to "something you design inside the amp," and now to "something whose place of design you choose."
Modern metal designs the "input signal," not distortion
At the very outermost is modern metal.
Tight, well-separated chugging with no swelling low end. That sound doesn't come from just deepening the amp's distortion. Rather, it thoroughly designs the input signal before the amp. Condition the bands with a front-stage booster/EQ, tighten the gaps with a noise gate, and only then run that crafted signal through the high-gain amp. More than half of the distortion is decided outside the amp.
In other words, modern players aren't choosing "the amp's sound" — they're designing "the signal put into the amp." The initiative over the phenomenon of distortion moved from the amp's circuit to the signal design ahead of it. This is a far more precise extension of how, in the era when distortion was "added," it was added at the front stage with a pedal.
Designed distortion can't be imitated by amount
Put a recording-and-reproduction viewpoint here.
In the era when distortion was "added," if you captured the raw amp, the rest was a matter of how you add. Pedal and volume could handle it afterward. But once distortion is designed, the story changes. Match the same Gain position and you still won't arrive at the same sound. The layout of gain stages, the state of the front stage, the power stage's feedback, and the input signal it receives — only including that whole make-up does it become that distortion.
That "same Gain equals same sound" stopped working is because of this. Designed distortion can only be grasped, not as numbers, but together with how it's assembled.
What CSL keeps in a profile is exactly there. Not good distortion itself, but what structure of distortion one amp made, under given conditions, with what playing feel. The part you can't reach by imitating amount alone — structure and response — kept, conditions and all. Precisely because distortion is designed, there's meaning in keeping the state in which that design was working, as it was.
In short
Distortion began as something you "add," a byproduct of high volume, added afterward by the player with pedal and volume. Eventually, through cascade circuits and drive channels, it became something you "design" inside the amp, and now it's something whose "place of design you choose," including the front-stage input signal.
So good distortion can't be discussed by amount. What structure, where, in what order was the distortion made? When choosing a high-gain amp or pedal, look at "where is this distortion designed?" before the depth of Gain, and you'll see what that amp, or that combination, was designed to aim at. Listening to distortion by structure, not amount — that's how to listen in the era of designed distortion.