Hi all, I was wondering if any of you had ever seen anything like this problem. I have this WT550 that I've owned for about 15 years. I also have a number of Avatar cabs that I've owned longer. I was using the SB112 and the eden as a practice rig, and I noticed that the volume would fluctuate and drop off almost completely after about 15 minutes of playing time. It's a really reproducible problem, and it happens with all 3 of the cabs I have (all 8ohm, an SB112, and SB126, and an SB115). So I took it to a good tech in the area, figured it was the thermal circuit. He kept the amp for about 2 months and eventually just cleaned it up some and returned it. He could not reproduce the issue. So I get it home, and I can reproduce the problem just as before. So out of curiosity, I hook up 2 of the cabs instead of just 1. With 2 cabs at a 4ohm load I can't get it to fail. What's happening here?