Having connected the output wiring properly this time (had wired my output jacks to metal-rimmed mounting holes near the contacts rather than the contacts themselves), I was eagerly awaiting the new transformer. It came yesterday. Like Christmas in May - which, having been raised Jewish, is saying something.
Soldered the transformer wires where they needed to go, hooked everything up, powered it on, turned on the amp, turned off the mute switch, turned up the volume, and - Music! Yee-hah!
Disappointing news from the trial run (no chassis or ribbon conductors, just everything laid out and hooked up with regular wire for testing):
Everything is soldered and connected, with a 1A fast blow fuse in the IEC inlet. When I plugged it in this morning, the transformer (an R-core transformer I purchased separately from the boards) got piping hot to the extent that I smelled plastic and was afraid to leave it plugged in long enough to listen to anything. One thing I did, though
A very nice person has provided me some DAC innards, which will give me the opportunity to put together a semi-customized DAC that employs some thoughts I've picked up from various smart people along the way. Said nice person has requested that his/her identity and that of the innards remain confidential. Out of respect for that request, I'd ask anyone commenting as this project proceeds to please refrain from speculating on those points.
The thoughts I'd like to try to put into operation: