OK, here are the results of thermal stress test.
I hooked up input to one channel and let it the unit warm up driving that one channel at 40 watts. I logged THD+N during that time and got this:
View attachment 19779
There is some equilibrium that occurs after 3 to 5 minutes but then thermal effects start to set in and distortion increases a bit (1 dB or so). An arrow to the heart of people who think they should leave the gear on 24/7.
I then jacked up the power to 330 watts or so and started to cook the unit. Here is the above graph again:
View attachment 19782
Here is the power measurement showing the shut down with power dropping to zero:
View attachment 19783
I had hooked up a 4-channel themorcouple and here are the results at the end of warm-up (left) and max power (right):
View attachment 19784
As you see, the large power supply heatsink was the hottest at 81 degrees. Strangely, shortly after I took the above right picture, two of the thermal probe started to glow red in the middle and completely melted the insulation!!! Cheap junk.
Thermal imaging showed I had probed the wrong things:
View attachment 19785
As noted, the hottest components were actually the inductors/transformers! Both in the amp and power supply. Max temp for the large power supply transformer is about 101 degrees C. Wonder what their wire insulations are rated at.
After the stress test, I ran a power versus distortion test:
View attachment 19786
Power increased to 315 watts which is not much more than when both channels were driven. Distortion performance is the same as when the unit was much cooler in the original review.
Now please me go and cry over my damaged thermocouple meter.....