I continue to be mystified... Nothing has jumped out at me yet to be the culprit in why this thing is idling hot. I haven't really tried to be precise yet in setting the bias since I am assuming that something is amiss, just getting it in a ballpark of 2 or so mv. The bias transistors appear to be doing their job since the readings immediately drop several millivolts when the cover goes on. With the bias approximately correct, I'm still getting the same 112-115° readings today. In looking at the possibility of oscillation, I tested the output with a dummy load and a 150mv 1khz signal. Both channels were putting out just at 1 watt and around 8.2V. This is the output on the scope, which looks very clean to me: And the same output expanded to get a better look at the peak: Didn't grab a picture, but the square wave version of the same signal looked great. Running this signal into the dummy load for 15 minutes or so at the 1 watt level slowly raised the heatsink temp up to around 124°, which is troubling. I am still getting dc offset readings in the 60mv range, but am unclear as to whether the source of those high levels might also be at the root of the temperature issue. Looking at the parade of outputs, I checked them all with the temp probe and found them to all be within a degree or so of each other. Next was looking at individual bias readings for the outputs (the ones I can actually get to) and found one thing that I am curious about. Assuming that the manual's specified 180ma also includes the bias current for the driver transistor, it made sense to me that individual outputs would have a correct bias current of 36ma and testing directly across several of the emitter resistors gave appropriate millivolt readings. I did find however, on the left channel, that the 2 of the NPN outputs were reading 2mv lower than the other, so I am concerned that the necessary current sharing is not happening. The way these are wired, the emitter from the driver is split into two and two on the outputs, with a 4.7ohm resistor in line to each pair. My first thought was that I had mismatched these resistors and the two pairs were getting driven at different levels but all the resistors match. I am afraid of gain mismatch on the outputs, despite all of my efforts to keep them consistent, but the fact that the millivolt readings are consistent on either side of the split from the driver makes me think that maybe there is another explanation. Also makes my head hurt, so that was where we call it a day and hope that inspiration strikes or a helpful reader can point out where I am being really dense.