I'm a tube head (sounds better than vacuum head) and I've built a number of projects over the years.
I have a stereo power amp I built a few years ago, mostly out of surplus. The whole of the circuit is a hybrid utilizing pieces of other circuits I've felt were good designs: the power stage (not the power supply) is push-pull parallel beam-powered tetrodes, biased pure class A, which drives an output transformer (secondary impedances are typical 4, 8 and 16 ohms); the phase inverter and driver stages were styled after an obscure 50 year old circuit I came across once, which I forget the name of (not like the type commonly found in guitar amps or ultralinear circuits); no elaborate coupling of the stages, though there are stabilization circuits in the power amp section; completely open loop (no negative feedback circuits); and an otherwise relatively common voltage divider network design for the power supply (with two large power transformers wired in paralell, and oversized capacitors). I have a provision on it which allows for adjusting the contour by introducing a tuning circuit in the input triode plate supply.
It has a nice even frequency response from 25 Hz, develops incredible dynamics, and is CLEAN and FLUID at all levels! This amp will crank like hell and not break up at all. Overall sound is amazing. I have had numerous and intense praizes from individuals, sound pros and audiofiles alike.
Who cares about the numbers. Some of the numbers I get when I've bench tested this thing would make anyone the laughing stock of the AES. The only data I will share here is that It will develop 80 watts per channel before clipping on a 1000 Hz sinewave.