Well... it works... and it sounds amazing. All my worries about hum were completely unfounded. This is the quietest amplifier I think I've ever heard. That is until I play some music through it and turn the volume up. My wife came home while I was testing it so I put some jazz on (something she can appreciate) and her jaw hit the floor (which, believe me, is not a common sight). I've heard the sound will improve over the next few days as it 'burns in'. What? It can get better?
The sound is strange -- hard to describe. It's really clear and detailed while at the same time kind of full and deep. The bass is amazing and it has this old-time fullness that is often lacking today; I guess that could be the 'triode' sound. Whatever it is, it's great. It's also amazing how loud 5 watts per channel can be. I was expecting much less volume at maximum. It's way more than enough for my living room. This was definitely worth all the blood, sweat and tears. The only thing left to do is put the feet on the bottom plate.
Thanks to everyone, in particular Tom, without whom I would probably not have succeeded. And Shannon, if you're reading this, thanks for making your designs and circuit boards available for everyone to enjoy.
I'm very happy
John