Thanks for this posting jhstewart. Out of curiosity, what's the asymmetric triode/pentode in the schematic? It's hard to read. It looks like 6DN8 but that can't be right...
I am particularly fond of the 26 configured as a diode to fix the bias of the 2A3s. The "Sound" article is near identical to the RCA application note available from John Atwood's excellent web archive (here: https://www.one-electron.com/Archiv...mploying Type 2A3 Power Amplifier Triodes.pdf)
I’ve got a couple pair of NOS 2A3’s but finding worthy transformers without selling a kidney is the hard part.
US production 2a3's from the 60's and earlier are VERY NICE. But they are pricy... I have some very inexpensive (actually got them for free) China 2a3's from the 1990's which are really great and are still going strong. Tubelab (George) has run these old cheap China 2a3's at higher voltage successfully too.
If you are looking for some surprisingly decent yet inexpensive 3.5k OPT's for SE 2a3, I have a few Demonkleaner. You can PM me about them - they're Japanese.
If you are looking for some surprisingly decent yet inexpensive 3.5k OPT's for SE 2a3, I have a few Demonkleaner. You can PM me about them - they're Japanese.