The BYOB amp's stock heatsink is a TO-3 heatsink meant for metal can power transistor. It does not touch the tab of the chip at all, and so it never gets hot. I can only guess that it is there just for looks. The chip has thermal protection, but specsheet says it will sound better with good cooling, not to mention prolong the life of this expensive little amp. I first replaced it with a .06" thick x 3" wide disk of aluminum and that got much hotter. I found a heatsink from ThermaFlo which would have been 3" x 3" x 2" with lots of fins and <2C/W resistance. The online form quote request got no answer from Therma flo, direct email no response. Phone message no response. So I found my local Thermaflo distributor, after a week they wrote back, "You are small peanuts buddy, go play in traffic. You can order 200 pieces for $4,000 and they will be ready in 10 weeks." (paraphrased, they were actually very nice.) So I got out the trusty Mouser catalog and found this nice piece. It is made for a DC/DC converter, and is just the right size. A little heat paste under and screwed it into the wooden base. It doesn't fit the stock holes so I had to drill some new pilot holes. I also had to ream out the mounting holes on the sink, they were too small for the stock screws.
I think it looks better than the looks only stock version, and now it can finally shed some heat. Just before clipping (10W->4R) the chip dissipates >18W! No heatsink is suicide for this little gem. I hope it helps hold off clipping for a little longer.
Mouser part #567-547-95AB Wakefield DC/DC Conv QUARTER BRICK VERT. $9.95
