Just in case anyone else experiences this I thought I would mention it and save them some trouble. My V-amp2 began losing patches a while back. Any patch that I changed from factory, when I powered up it would suddenl sound really muffled and buried, no changing of any paramter would help get it out. The ONLY thing that helped was resetting that patch back to factory default. From there I could change parameters, choose amp types, etc. okay. But if I did, and power down and up again back to the same problem. Along with that some of the effects would ping-pong in the stereo field even when I picked some other effect. Even then, after power cycling, the "bad patch" would come back. I figure it is because I cannot save the new patch OR EVEN save the fact that I had gone back to factory default. I know, anytime you save patches you have some kind of battery in the unit, to keep it in memory. Thing is, there is NO mention of it in the manual at all. I emailed Behringer, and they acted all coy...I mean I SPECIFICALLY asked if this was typical of a battery going bad, and they acted like they never heard of a problem like this, and furthermore needed(this is where they get you....ask for ALL kinds of version numbers, when bought, etc. so the person just gives up) mor info to even help me. Took days to exchange email cause they don't answer direct you have to fill in their panel at the website. Anyway, this is a little premature, but I took out the 4 screws on the back, carefully lifted the cover off (it is well built as far as accessibility) and there was the little 3v battery. Taking it in tomorrow to get a new one, but more I think about it the more I am sure this battery is just dead. I'll post here again when I confirm that. But it all makes sense.