Hello, I've bought a used SVP Pro preamp and it really worked fine for me, but since the last rehearsal the preamp really made me mad. After playing for about 2 hours the svp was still under power but there came no sound out of it. I had to turn it off and wait some time and then it worked fine for about 10 minutes and the same problem came along again. Was the preamp just overheated? What if it happens on a gig........ Anybody who had problems like this before? Please help!