I'm just downright confused. I realize that a computer power supply may not be the best choice for this application, but it's what I had around. Also, it doesn't seem to be exhibiting any unstable behavior.

The label on the side of the PSU says the following (i'm trying to use their formatting):
Max DC output
+12V
0.3A~
9A

Does that mean it puts out between .3 and 9A? I've measured the voltage and current going into the empeg player under every condition I can think of. Here is a table:

standard empeg AC adapter:
15V 0.4A
computer PSU:
11V 0.4A

Both the current and voltage coming from the PSU are very stable. During the 'power failure' the current and voltage remain the same, until the empeg switches back on (it comes back on about 2 seconds after it goes off), then the current jumps to 0.7 amps and then settles back down to 0.4.

Rob, what is the best way to test the PSU to see if the thermal cut-out is happening? If the problem was the PSU wouldn't I see a drop in voltage/current when the 'event' happens?

I appreciate any help, thanks!