the Xpression should be connected to the Mark's FX loop. Isn't there a FX loop bypass on that amp? use that feature to "bypass" whatever's in the loop with a 25 - 50% wet/dry mix. Changing the amp's channel will need a switching system (like a GCX). Since the Xpression doesn't have an external switching (like a G-Major), you might need a switching system along with a
midi pedal to make it all work.
Actually, some midi pedals have external switching so you might have to do extra research on which ones have this feature.
Reg
