I don't even have this amp one month. Last night as I was playing the volume drop to barely audible. I turned the FX Loop off & the volume came back. I tried the FX Loop again but was still no there was no sound. I turned the amp off & then on & the FX Loop worked again but it's not as loud & doesn't sound the same it sounds a bit fizzy & much quieter with & without the FX Loop. All pre-amp tubes are glowing & the 2 PT tubes are glowing. I'm shipping it back but I'm curious as to what the problem could be or if anyone else had this problem?