[Boatanchors] What to do about 811A vacuum?

[Bob D.]

If it hasn't crossed the line to the world of BAs, let me know!

My Tentec Centaur HF amplifier was designed to use the surplus Soviet 811
like that was sold as Svetlana brand. In this amp, they are operated at
1800V which is a good bit over spec.

None of the purveyors of tubes from the East will promise 811A operation at
this voltage.

Current 572B offerings are reputedly lacking when it comes to emission life.

If anyone has a better option or caveat, I'll probably be ordering three of
the old stock Cetron 811A from Surplus Sales,

Suggestions?

Thanks.
-bob ah7i em73ts