Negotiations for time/place to commence shortly. Of course I don't have much to listen to these days but I should be able to provide some interesting sources.

Interesting sources is an understatement! Sounds good to me.

I do have a half dozen 872-A rectifiers, but I need a filament ransformer the size of a lawnmower to run them. Bummer.

I have a couple of those which I found in a surplus store and was planning to use as a giant night light. The local surplus suppliers didn't have a suitable transformer so I ended up using a computer PSU to power the filament. The project didn't get very far since I didn't have a socket for the tube and it was entirely put together with clip leads.

6.75A @ 5V, yeesh.

My RCA book says 7.5A, up to 8A if the V is 5.25. Upshot is only dropping 10v I suppose.

15 amps for a full wave setup? It would make a neat nightlight, but the transformer would be quite a heater.

These things are huge... [ATTACH=CONFIG]2929[/ATTACH]

After more careful measurements I found my input stage's voltage a bit high relative to the output stage, so made some adjustments there. Also had to make an adjustment to my filaments; they weren't floating high enough. It sounds good, and isn't running quite as hot, though still pretty hot. The 12B4As are at 23ma.

I want to try some tweaks with the rectifier next, then have another pair of OPTs to compare.

Another shot in the dark-