I have a Peavey VYPYR75 Modeling Amplifier and after about 10 to 15 minutes of playing on it the sound through the speaker slowly fades out and then I hear a pop from the speaker and there is no sound output what so ever. The tech. from Peavey I talked to said this was a malfunction in the Headphone jack muting switch causing the speaker to cut out. I know this isn't the case as the headphone jack doesn't work after the sound quits. The amp acts and sounds like the main amp board is shutting down. Similar to when I turn the power off on my smaller practice amp the Peavey Rage 158. I was hoping for some useful suggestions. I also asked Peavey for the schematics for this amp, over a week later... still no response.