Mk ...
Mk said:
Ahha! So this is why Paul Gilbert
I still have no idea what that says, but amplifiers are different now.
True, amplifiers ARE different now, but so are the tonal qualities they produce.
"Distortion" is one INCREDIBLY complex issue.
"Distortion" is caused by an amp "clipping" the signal it's amplifying. And "clipping" is a pretty good and descriptive term for what's happening to the signal.
Picture a nice smooth sine wave. It's got no really sharp bends in it.
"Clipping" happens when the amp tops out in how much it can amplify the signal. As a result the top of the oh so smooth sine wave gets "clipped" off. So now the sine wave is no longer smooth at all. It goes up smooth, but then, before it reaches the top of the curve where it would normally transition from going up to going down in a gentle smooth curve - it *very* suddenly goes dead horizontal, in a straight line, because the amp isn't capable of outputting a higher amplitude signal. That means that the top of the sine wave is literally cut off, which leaves a kind of flat top to the curve as if you cut off the top of the sine wave (or any other otherwise "smooth" wave) with a razor blade.
Now here's the thing. A pure sine wave HAS no "upper harmonics". None. It's a "pure tone". Which is another way of saying that the signal has no sharp corners to it. It's smooth, and "smooth", as in no sudden changes to the slope of the curve, is analogous to "no upper harmonics".
A saw tooth wave is just the opposite. It has extremely sharp bends in it, i.e. extremely sharp changes in the slope of the curve, which is another way of saying that it's LOADED with upper harmonics.
It's the presence of upper harmonics that make for sharp changes in the slope of any curve.
So by clipping off the top of an otherwise smooth curve, thereby forcing the slope of the curve to change suddenly, you're adding upper harmonics into the signal.
And THAT is precisely what "distortion" in an amp is DOING to the incoming signal. It's adding upper harmonics to it that weren't there originally, even to parts of the signal that weren't just pure sine waves. Which RADICALLY alters the perceived tonal quality of the signal.
Now the thing is, that'd be an easy thing to duplicate if all amps clipped off the same frequencies at the same amplitudes, but they don't. Not even CLOSE. Not only do different brand and models of amps clip different frequencies off at different amplitudes, INDIVIDUAL AMPS of the exact same make and model, "clip" at least slightly differently, due to, for example, tiny variations in the length and path of the wiring inside them!
This kind of over sensitivity is also what makes "tube amps" "moody". As in the very same amp will sound just a tad different, on different days, even though all the settings on the amp are the same. The difference is usually VERY subtle, but trust me, MORE than enough to piss off a musician who KNOWS his amp COULD sound better, just a tiny bit better, if it wasn't in a pissy mood.
Solid state amps have circuits in 'em that try to mimic the clipping dynamics of popular classic tube amps, but VERY few of 'em come anywhere close to "the real thing" to a trained ear.
When musicians say that a particular type of distortion sounds more "natural" they generally mean that the distortion sounds "smoother", less "poppy", or "farty" sounding, more velvety. All of which are very metaphorical terms for variances in how the signal is being clipped that would be EXCEPTIONALLY difficult to boil down to more technically sophisticated, not to mention more accurate terms.
That help?