I know several people have vintage 6L6's, EL34's, KT88's, etc..
Do you build your own amps? The best suggestion I have is to drive the tubes gently.
Some thoughts:
1] Use a tube rectifier such as a 5U4
2] A power transformer that is no more than 700 volts with a center tap
3] A 5H choke, DCR approx. 50 ohms, 20uf before and whatever you like after it
4] Use tetrode mode wiring and a low screen voltage (290-300v or so)..do not use ultra linear taps
5] OPT's with a primary impedance of around 7K
6] DC Biasing
Output power will be around 18 watts/channel max, not much different than a P-P 6V6 amp. Sound quality will be accurate and full with the proper circuit. Your vintage tubes will LOVE you! Play them every day without concern. As a bonus, this kind of power supply can be insanely quiet. Treat yourself to DC filaments for a 100% quiet background. The B+ will be approx. 350 volts under load with properly biased 6L6GA's or metal 6L6's.
Note: With EL84's try using a 600v w/ center tap transformer and 10K primary OPT's.
