OK, my Trace arrived today. Now, I do not have cabs that are powerful enough for the amp, but obviously I'm thinking I can play at low volumes. Well, i plug in, and to my unknownst, the mute switch is on. The mute switch is different from the other Trace i've used previously. I'm thinking it's off, when it's on. I am still getting some sound, so I think, for some reason, that it's just 'cuz the speakers won't pull any power, hence low vol. however, when i go test the mute switch, I've got the gain knobs set at 9. FEEDBACK. INSANE FEEDBACK. Enough so that, one of my speakers has a small tear in it. I unplug, and give both the amp and cabs a while to settle down. I mean, it was so intense I almost crapped myself. Took away a few years of my life at that I'd think. After letting it settle, I turned back on, and played for a good 30mins, and all was well, all knobs and sliders work great. SO i go for a shower, lunch and misc things, so about an hour at least later I go to try 'er out again. Same bass, same set up, and for 2 minutes the volume was coming and going - like a wave; as if someone was very slowly turning up the volume to it's current setting, then turning it back down to almost nothing. ...What have I done to my power amp!? Ahhh! What I'm running: Trace AH250 GP12SMX two Laney 1x12 cabs, 100 watt RMS, 8 ohm each cab is in a different channel on the amp. Thoughts?