Seems hard to find C3g tubes but here I came across an adapter:
Price seems steep - $35 for one.
Meanwhile I am listening to the combination of RCA 6SN7GT power tubes and a GE 6BX7GT as driver. Really very nice. GT means Grand Touring if my amp was a car. Now GT just means Glass Tube.
I'm afraid that my beloved 6N6P-IR tubes will be relegated to the the dust bin......At least they have good company; some 300+ sibling tubes.
Here is some (blah blah) listening impressions:
Super wide, airy and open, extremely spacious 3D holographic sound stage, super detail everywhere without being etched but very musical instead, very powerful, fat and detailed bass that goes really low, pinpoint imaging and instrument separation, sweet midrange etc.
On the con side: A little bright but not sibilant, could be quicker with more slam. It is also interesting to note that this tube combination needs to warm up some 20 minutes to sound its best.
Nah, strike the blah - this is real, this is cracking!
British Slang: Cracking - If something is cracking, it means it is the best. Usually said without pronouncing the last "G". Thanks, Nic.