Alright. I have a Crate BT-350 (hybrid) amp. A while back, it went in after I turned on the power switch, only to see flecks of sparks fly out of it when it cranked on. It finally gave out, and it cost 80 bucks to replace (Some BS like "It was hard to get to the switch). Now, after working fine for a while, during playing, the sound will just drop completly. then flick on, then flick off. Now, the amp seems to be running fine, power is getting to it, no light flick on or off or anything like that, the only difference is that sound mute. Thats what it sounds like, someone muting the sound and odd times. After turning it off, then back on, it relives the problem. It's not a bad cable, and it's not my bass battery....(I don't think. I just replaced it). Unless someone played it and left it plugged in for a long time. But I doubt a battery can go dead in 3 days. The battery life has always been great, so I'm thinking it's a amp problem. I have never replaced the pre-amp tube.... maybe I should?