I have a Boss GT6 with the power supply that is 1volt higher than what is needed. The store I bought it from said there wasnt a problem if its one volt higher. when I got home, I plugged it in and it worked, the only thing that was wrong was that there was no sound coming out of it. I checked the cables and they work perfectly fine. Then I figured I would check the tuner. It worked. Then I cranked my amp up about halfways, and I hit the strings hard and you can hear the strings that I hit very little coming out of the amp. Could this be a input/output jack problem? Please help.