I have an EBS 350 head that I recently sold to a respectable member here. I had to give the guy a refund because he says the amp began to make crackling noises after a couple hours. He shut it down and wouldn't turn on again for a while. Then he took it home and ran it without an instrument plugged in. Turned it off after an hour and it wouldn't start back up for 30 seconds or so. I've never had any probs with the head but B4 I sold it though I had never tried to restart it right after running it for any length of time. I just got it back and it is doing what he said. Any Ideas? Is this just normal for this amp? It runs cool. It's definitely not overheating. I will probably have to sell it again because I'm still pretty short on funds, but I guess I may have to take it to a repairman first.