- Jun 19, 2011
- europe endless
So just a fact: saturation is saturation regardless of whether it comes from tubes or not. Clipping is a physical phenomenon. You can see it on an oscilloscope. It's not little elves in a vacuum. Ok sure a tube amp interaction, preamp and power tubes blah blah bah, but if all you want is "warmth and a bit of drive to your tone" then a good pedal will sound great.
but saturation isn't the same "regardless of whether it comes from tubes or not."
with triodes, basically the waveform starts soft clipping asymmetrically, then it hard clips symmetrically, then it starts getting hard clipped on one side and unclipped on the other, and does this pulse width thing with the differently clipped portions of the wave as it gets slammed harder. even order harmonics are more emphasized at various points. the signal on the grid distorts too.
but it also goes through the power amp, which adds crossover distortion and clips it symmetrically, emphasizing odd harmonics (pentodes and differential configurations). the transformer smooths it out a bit, and may introduce weird notchy stuff. but generally you do end up with something pretty squarish which can look and sound a bit like the output of an OD pedal.
so yeah, it's possible to get a similar sound as the final product of the whole amp riding hard from clipper pedals, or possible to get a similar transfer function as a triode operating at a specific point just clipping the signal asymmetrically. but it requires some effort to get the transfer functions the same or similar enough through the whole range of gain, to get the right response from transients. not many out there actually trying to get SS to do that.
you could argue this all has more of an effect on feel than it does sound, but "saturation is saturation,” is a bit of an oversimplification. the saturation of the device or config is going to mess with its operating point and change how the input maps to the output, and it's clearly observable on a scope.