I read another post earlier about a L1 Compact owner with the same problem I have from time to time. There is no sound when my guitar is plugged in. I have to jiggle the volume control a bit and turn the unit off and on, before the sound comes back. I never know when this is going to happen and it is as bit embarrassing when I'm about to perform and the sound goes out on me. Any assistance you can provide would be appreciated!