Would I have to be constantly playing with my Bongo (18V preamp) at fraction volume? because I always end up hitting the volume knob while playing and it turns, so I always leave it full so I have a set marker to go back to. would full on 18V distort the compressor? should I use a volume pedal in front of everything to get them even? can the bongo function with only 1 9v battery? thanks all.