"I have no idea what the thing is, but ..."

Actually it is pretty nifty. It is a module with a dual channel 50 watt audio amp self contained and smaller than a PCI card for your PC. you putin 120 VAC, the inputs and you got the outouts. It is a SMPS p[ower supply with a cass D amplifier all on one board. There are no heat sinks at all except the copper on the board.

In this case, the two channels are wired in a BTL or bridged coinfiguration yielding 180 watts. It was in an Eden bass amplifier.

Don't get me wrong, I like the efficiency of class D. I think it is a fine and dandy idea, but when you stick power coomponents on a four layer board and they are al surface mount, it is obviously not meant to ever be repaired. It is a unit, and shall be replaced as such.

And now, comes across the bench a Peavey, coupl hundred watts, class D, weighs nothing. Again, it is not the class D circuitry that is the problem, it is the fact that it is not built to be serviced.

What's more, these things are supposedly for professional use, and as far as I am cincerned, they are not reliable enough. If I put the heftiest transistors available from Digikey in an amp, make sure the fan works and everyrthing, that musician can be fairly certain he won't need to change out amps in the middle of the gig. With **** like this ?I have no control over the process and what fried last time is likely to fry next time.

This **** takes us all out of the loop.

And that is what engineers do.