I've been using this amp pretty heavily for about 6 years with no issues. Last time I had it out there was significant buzzing going on at about half volume, especially lower notes. Sounded like a snare drum vibrating, but after searching around the room I determined the buzzing was coming from the amp itself. Turned down or plugged into the -15 input and the buzzing went away. The next day I took off the front panel and pulled out the speakers but didn't see any damage or anything that would cause the buzz. I quick used my phone to record a bit of us playing for reference. Any theories??? https://drive.google.com/open?id=0Bx6GwsOJtfulSzUxR2NWYXgzSFE Amp Manual: http://www.ampeg.com/pdf/BA210SP.pdf Thanks in advance!