Preamp tubes in power amps

Better 6922 for the preamp, but remember that the manufacturer designed your unit with modern sounding tubes in mind so you want something better in that direction meaning linear sounding tubes.
Believing that your pre has Sovteks or EH I would go with Siemens Halske E88CC and Cca up to 1967 production, for a classic tube tone, or their bigger brother E188CC same period, for more bass and treble. But definitely i would try to find some Voskhods 6N23p 74-79 production for their better flow and the info retrieval at a much lower cost.
Of course you can try anything from that family and you can get better results from the ones you already have as long your pre does not push them too much in which case your choices are limited.
A good move is the check with BAT if that is the case before spending your cash.
For the power amp I would check to put the best I could afford in the cathode follower position leaving everything else as is.
A new world.

I’m not familiar with your components, but you want to first upgrade the input tubes or voltage gain tubes, same thing, I think. As to whether the preamp or amp would have the most impact, I’d guess the preamp unless the tubes in your pre are not used for voltage gain and are in the amp.

That’s unfortunate about the 7DJ8s, but it shows why you need to talk to the manufacturer. 7DJ8s are often used as subs for 6922s these days.  Did you talk to Upscale about the problem?

Thanks again.  Yes I did tell Upscale about the issue.  They tested all the tubes and sent the survivors back to me, but I haven’t used them as the only 6922 sockets I have are in the BAT.  I can’t put them back in there.

The only gripe I have about Upscale was his statement about 7DJ8s being a perfect substitute ...”trust Uncle Kevie on this one.” Not “make sure this is ok with your gear.”

Oddly, Victor at BAT seemed skeptical that changing tubes would have much impact.  

See if you can get Viktor to talk to Upscale or get an email from him stating the 7DJ8 is not suitable for his preamp and pursue the matter with Upscale.  Did Upscale know that you planned to use the tubes in a BAT pre?

Some manufacturers advise that you can't do better than the stock tubes because that's what they designed the pre or amp with, others encourage tube rolling. I guess unless you hear from someone who has the same components and had success tube rolling, I'd follow the manufacturer's recommendations.

Thank you. This is helpful advice.

Upscale didn’t know. I don’t think they should be quite so certain in their marketing materials that 7DJ8s work anywhere.  But I couldn’t say that there was anything specifically said to me, or omitted, that was a problem with Upscale. I ordered several sets and had ruined most before Kevin could respond. The tubes DID sound good...

The issue was years ago, and so I’m not going to pursue it with them now. It comes up mainly because at that time I decided not to try NOS tubes in this preamp again. But now that I have it available to my best amp/speaker combo again, I am again wondering if some NOS would add magic.