I just picked up a new Gibson R8, and plugged it into my CR this morning. I played for a good 15 minutes, both amp and guitar sounded great. I kept everything on while I sat down to my computer, save turning the volume on both pickups down to 0. After a few minutes I started hearing a hum, checked the guitar volume which was indeed off, played a few notes that sounded strained then unplugged the guitar from the amp, and the noise got worse. Looked in back and the right two 6L6's (it's a 100w), were glowing a very hot red, and the smell of overheating circuits became evident. I immediately shut the amp down. I mean I've played 125 straight gigs with this amp and was just remarking to myself the other day how reliable and durable it is. Any theories? Too early still to call Joe or Bill.