@atmasphere wrote "you hear distortion as tonality"
Could you explain? Thanks!
@o_holter Our ears use harmonics to tell the difference between a clarinet and a trumpet. When harmonics are added to a signal (such as when that signal passes through a preamp or amplifier), they change the tonality of that signal by adding harmonics in much the same way that different clarinets sound different because their harmonic structure is different.
IOW distortion is interpreted by the ear as tonality. The brightness of traditional solid state is caused by low level higher ordered harmonic distortion; the 'warmth' of tube equipment is caused by the 2nd and 3rd harmonics. So you can see that its important for the distortion signature of any amp or preamp to be benign, and also that the 'sonic signature' of an amp or preamp is actually its distortion.