I have an Ampeg B50R that has a problem with the gain (volumn) knob. If you turn it all the way down and then slowly start turning it up you get no sound until it's at about 1/8 of a turn and then it's too loud. I can't play at a real quite practice volumn. It's still under warrantee but if there is something easy I can do that would beat sending it back to Ampeg. Thanks.