Title says it all ... I've seen some real raves about the sound of the 6L6 variants, and the TungSol new issues (6L6GC-SCR) look like an outstanding deal as well. They certainly do cram a lot of plate inside the bottle, and it looks to have some interesting kinks in the structure as well.
Cathode type: Indirectly heated
Heater voltage: 6.3
Heater current: 900 mA
Max dissipation Watts: 30
Max voltage: 500
I expect there'd be some power loss for total output, but not sure how all that would work or whether these would bias up properly. Real world experience?