I finally got my 12 watt amplifier working and I found out the hard way, by burning a nice impression of the top of a heatsink into my finger. I found one track I had not cut, made that cut, powered up the amp and discovered that what was previously cold was suddenly and very painfully burning.

Anyway, at least it works now, I can build the other channel, build an enclosure for it and get started on the next project. It sounded pretty good by the way.