[geoff]

On 11/02/2019 3:49 PM, Scott Dorsey wrote:
geoff wrote:

And then there is the solid-state v. vacuum tube predominant even/odd
distortion harmonic thang, as you obliquely alluded to in your second
paragraph.

That is a useless oversimplification which is no way correct, and it
comes from an IEEE Spectrum article in the 1980s. I wish people would
stop repeating it.

That article was talking about predominant distortion at low levels
without feedback, caused by the device characteristic itself. The
thing is, we don't actually use electronics that way. We use circuits
designed to minimize distortion using techniques like local feedback
and push-pull amplification, techniques like constant current supplies.
Once you do that, the distortion spectra all change in ways that are
not so cut and dried.

And of course, you can't generalize low level distortion to clipping.
When you clip a waveform, you generate odd harmonics. Generate enough
and you get a square wave. It doesn't matter if you do it with tubes
or transistors, in the analogue domain or the digital domain. That is
what clipping does.
--scott



We are talking specifically in an electric guitar context no ? Hardly an
amp designed to minimise distortion ?

So that would be why distortion from over-driving a solid-state guitar
amp (discount 'modelling amps') is just as pleasing as that from a valve
amp then - not ?

geoff