[AllanS]

Thanks much guys. I’ll take a minute to get the twist outta my knickers and move on.

[JackD]

Until the war in the Ukraine the 6N8S was the standard isssue tube with Supratek preamps and many owners used them for years.  I listened to the pair that came with my first Supratek in 2019 for a bit and found it acceptable and better than the current production tubes I had heard.  As I had a healthy stash of 6SN7 tubes I had aquired in the early 2000's I switched over to what were much better tubes.  I have used them again as driver tubes in a Don Sachs DS-2.  A good emergency tube to have around in case of a tube failure. But no they won't hold a chance against my 40's Sylvania's or Raytheon's or RCA's nor the 50's Tung Sol's.  A tube to try if you find a pair fo a good price are the late 50's-early 60's GE side getter.

[AllanS]

A tube to try if you find a pair fo a good price…

Isn’t this how it starts?

If a Chardonnay had presented itself a couple of years ago I might have my own modest stash by now. I’d been kicking around the idea of a tube pre but Mick’s “Guide to Buying a Tube Preamp” was my introduction to the discussion of tubes in general and the 6SN7 specifically.  I had no idea of the 6N8S history with Supratek.
Thanks Jack. 

I’m still a bit blown away that modern equipment and enthusiasts rely on actual components 60+ years old and that there are still enough around to keep it going.

[Rusty Jefferson]

....Maybe I'll just order with 6N8S and listen to them for a bit as Rusty suggested before swapping in the 6SN7.  $50 is hardly throw away but maybe they're doing me a favor.  I've pissed away a hell of a lot more for worse reasons.

Yes, it's an easy/good decision to have a baseline to listen to. It will also make it easier to determine the improvement or lack thereof when you install the NOS tubes with consideration to the added expense. If you don't have a baseline, you're flying blind.

Hopefully, you'll share your opinions about this, it may help others in a similar situation. 

[FullRangeMan]

Best place to buy Russian tubes is GSTube, they have 6N8S (novosibisk or Foton) now for $3 and 1578 Metal Base for $45.
https://www.gstube.com/catalog/?key=6n8s&submit=Find