Take everything you think you know and throw it away.  Everything you’ve ever accepted as truth about guitar amp tone, and what makes for great tone.  Shitcan it.  Seriously.  I’m not claiming that any of these learned notions are inherently wrong, but that we can expand our tonal horizons, and stand a better chance of achieving sonic inspiration if we keep an open mind.  The reason I say this is that guitar amplifiers – much like the guitarists that play through them – don’t really follow conventional rules of making sound.  Let me try to explain.

Whether talking about amps or effects, we’ve all heard ad infinitum that we need perfectly matched output tubes, true bypass, a certain brand and composition of capacitor, or a certain type of resistor.  Things must be hand-wired and hand-wound only.  Anything else is heresy, right?  A lot of this is snake oil, the rest, only marginally true.  But before we dive into this, we have to understand the psychology of sound.

Sound is ephemeral.  Unlike something we can see and observe, or read and interpret, sound is fleeting, and compared to our other senses, can only be described.  Measuring and interpreting waveforms, and comparing waveforms between the many options available to us ranges from impractical to nearly impossible.  So we’re only left with our memory and a sense of the aesthetic of sound.  Much like fashion, it’s quite easy to influence our perception of that aesthetic by applying artificial labels.

Let’s start with matched output tubes as one example.  Have you ever paid extra to ensure tubes were matched within a very small % for both GM and current draw?  Did you make sure the grid stoppers were matched too?  How about the ballast resistors?  The two halves of the phase splitter (of course this is pure fantasy for most LTP designs)?  Did you match the coupling caps between the phase splitter and the grid stoppers?  Dual bias control? What about each half of the transformer primary?   Were the tubes fully burned in before they were matched?  There are a huge array of nonlinearities and mismatches that occur from the time the signal enters the phase splitter until it comes out of the speaker cabinet.  Matching tubes to very close tolerances won’t change that.

So should I buy matched tubes or not?  Sure, it’s not a bad idea to have the output tubes within a certain range of likeness, just don’t pay extra for the ultra-matching.  You’re wasting your money.  By the way – and here is the big kicker – these slight nonlinearities and mismatches accentuate harmonic content (or at least are less capable of cancelling harmonics).  C’mon guys, it’s not a hifi, it’s a guitar amp.  Juicy is good.

The tone world is full of misconceptions like this, misconceptions that product vendors are more than happy to capitalize on.  Like the boutique pedal builders touting carbon comp resistors.  I guess someone forgot to tell these guys that carbon comps only do their magic at high voltages.  So they charged you more for adding noise to your circuit.  Congratulations on that new purchase.

By contrast, I came across a stash of coupling capacitors recently – ones that were used extensively in mid-grade Japanese hi-fi gear throughout the 80s and 90s.  But guess what, they sound great in guitar amps.  Amazingly clear without being strident or harsh.  No, they’re not Mallorys or Spragues or SoZos (or any of the other desirable brands).  They were also cheap – so cheap as to be almost free.  So why not use them?

But my point here isn’t to debunk a lot of the boutique zealot-isms.  It’s merely to encourage you to not worry if an amp is made with Sprague orange drops, cloth covered wire, NOS tubes, transformers wound on the thighs of virgins, or resistors made from mule dung.  Forget what you think you know and use your ears.  The sound either inspires you to play more, or it doesn’t.  And finding that inspiration is what it’s all about.  It just might come from things with no pedigree, just great sound.

Feel free to share your thoughts!

Andy

andy@blastradiuslabs.com