I have a Behringer BXD3000H amp head. For the last month, it's been randomly failing me, and now it's gotten to the point where it is no longer usable. Upon first startup, it works fine. After a random period of time at rehearsal, I will suddenly not be able to hear myself. I check it out with nobody else in the band making noise, and there is sound coming from it, but barely any. I have to turn the volume up nearly all the way in order to faintly hear myself play, and the amp normally rumbles the walls turned up halfway when it works. I have done all the troubleshooting I could think of, and I am positive the amp head is the problem, and not my bass, cab, cables, or pedals. I have swapped basses, swapped speaker cables, swapped instrument cables, removed the pedals from the loop and plugged straight into the amp. I have also tried my drummer's old Crate B150 head, and it works, so my 410 cab seems out of the equation as well. I am also led to believe this is a poweramp issue, and not a preamp issue because I played through the head without a cab and with headphones for nearly 4 hours straight and the issue did not arise then. So for some reason the amp randomly drops in volume to nearly inaudible levels, and it has to happen at the exact same time my warranty runs out... Sometimes this problem is temporarily fixed by quickly turning the amp off and on, but it only works for a few minutes at most after that. I also take a whiff behind the fan every here and then and I do not smell anything burning. Is there anything I'm missing here? I haven't treated the head bad at all in the time that I've owned it. I even built my own rack case for it when I got it (with proper ventilation). All of the troubleshooting I've done has been out of the case as well. I know it's a cheap head, but the reviews I found on it were great. Does this problem sound familiar to anyone? And can it be fixed, or do I need a new head?