QUOTE (LejonBrames @ Feb 2 2015, 11:08 PM)
What does the 'contour' switch do, and what does 'OFF' do?
OFF is still distorting the signal, and my harmonic analyzer shows no harmonic difference between the models, and only the EQ curve changes.
CONTOUR - Switches on extra tone-shaping for added control. ( basically it switches in a different response curve that adds different frequencies )
Your harmonic analyzer shows no harmonic difference between the models, but your ears should tell you a different story. As I said there are subtle differences between the models selected that you can further change with the bass, middle, and treble to get the tone that suits your song.
That harmonic analyzer would show something very similar if you had all the amps at your disposition to test out as the heads and cabinets would show different EQ responses.
OFF means the tonestack is not active, like a bypass, but you can still play with the tone controls. If it distorts maybe the incoming level is too high?