NOS RCA 6V6GT vs 6V6GTA

You are correct. The 2 watt difference only relates to a change in standards as to how plate dissipation was reported. For the longer story, see this post, all the way through @Bendyha 's post #25, where he gives a great spec sheet. My post #3 gives you the short story. Others fill this out with much more detail and knowledge than I have.

http://www.tdpri.com/threads/opinio...-current-on-vintage-6v6gt-tubes.735738/page-2

 

What about the RCA 7408?

001 by slider313 posted Sep 22, 2017 at 4:37 PM

 

002 by slider313 posted Sep 22, 2017 at 4:37 PM

 

7408 = MILITARIZED 6V6GT: https://frank.pocnet.net/sheets/049/7/7408.pdf

 

I had a similar discussion with Muchxs. The Sylvania 6v6gta was also a 14 watt tube. He put a set of those in my hot rodded Princeton Reverb clone.

 

In general I have not found a currently produced 6V6 that even comes close to the NOS 6V6 tubes in terms of durability. I don't know if the plate dissipation spec has anything to do with it and I am in no mood to analyze the spec sheets. I gave up electronic engineering years ago. There are a lot of subtle differences between tubes of the same type ... to be honest my ears aren't calibrated to be able to tell the difference between them. All I know is that the 6V6 tubes they make these days don't last long. It is kind of sad really. I carry spare amps these days because of tube amp worries ... In the 50's and 60's we didn't worry about it.
The cars they make these days are more reliable than the ones they made 50 years ago.You would thing that tubes would be indestructible by now ... not so. The difference between 12W and 14W is in the eye of the beholder. I think that max plate voltage would be more important than 2W even thought they are somewhat related.
I'm looking forward to the day when I can move back to solid state .... it probably won't be any time soon. Some of that is psychological resistance I think.

 

Just the opposite from my experience if you use JJ's. The JJ 's hold up to today's voltages superbly. I have two 65's: BFDR and BFD right now. The BFDR had the output tranny killed years ago by NOS RCA Black plates. Since then I'm all JJ's. Both these amps run about 460V on the power tube plates. About 10 years ago I had 4 BFDR's, 64-67's. They all ran very high on the voltage.
The EH 6V6's wouldn't last longer than 3 months gigging though... after two sets I went to the JJ's.

 

FWIW the JJ's do seem to hold up better ..... but I could still burn thru two sets or them in a year. I guess a lot depends of how hard you drive them.

 

I haven't had to replace a JJ 6V6 yet. On one amp.... probably 6 years or more at about 50-70 gigs a year. But as I said, the EH's would only last 3 months! I wont use a JJ pre tube though. Nasty things. :>)