One of my fantasies if I ever have the time again is to build an amp with lots of 12AU7s in the output. One design I considered involved 8 sets of 8 tubes (4 PP pairs). Each set would drive it's own OT. You *could* parallel them all for the right load, or you could run each one individually into one of the speakers in, say, an 8x10.
Why?
Why not?
Yes, you'd want custom OTs, but that's true no matter what.
Then again, I also want to build an amp with 4 pair of 6V6s in PP. Think Fender Deluxe output section but x4.
For bass? Something with just a pair of outrageous tubes never meant for audio. Or 8 sets of 4 6BQ5s or 6V6s. 480 to 700 watts.
The problem, of course, is that if much of anything fails in the output section, you have the potential for a catastrophic meltdown. Which, so long as you have a reliable backup, makes for a great-if expensive- show.
Legend for those not into tube terminology:
OT = output transformers
PP = push-pull