Sonic differences on High-gain vs Low-gain Amp

It depends on how the gain is changed, if it is increased by reducing the feedback or reduced by increasing the feedback, then yes there will be a change in sound quality.
To what the differences are, are up to how good/bad the amp behaves (technically) ie: stability, oscillations, output impedance, frequency response ect. with these increases/reductions in feedback.

Cheers George

Umm, if you have the amp, why not just try it with the 2 different settings and see what *you* think?

-RW-