GE 6L6GC bs RCA

If you can run them Golden Lyon KT66, is a pretty good valve. 

Unless you have a good set of RCAs Most are gone. I have two sets of Mcintosh RCAs 6L6s very VERY special.

I have a quad of Telefunken EL34s VERY special..

GL KT66, I was impressed.. re-issue Tung Sol 7581, reminds me of the old RCA BP. My Carys sure like them..

One other strong performer is the Tungsol KT66. It draws filament power in accordance with 6L6 spec, has the heavy KT66 glass and gives a great sound: mellow, articulated bass and sweet treble.

for what application??

used as driver tubes on Wavac Ec300b in front of EAT and Takatsuki 300b. The KT66 works best with EAT, the Sylvania Winged-C best with the latter

Its surprising to hear your collective comments on some of the Tung Sol re-issues and the Genelax.  Makes me wonder if the NOS craze is all hype.