[Tube-Swap] Substitute for 3-500Z tubes

[John King]

I have five linear amplifiers that use 3-500Z tubes and those tubes have become very expensive. I am TOYING with the idea of replacing some of them with Russian made tubes as they become bad, if I can find a Russian tube that will replace 3-500 Z tubes with just some mechanical modification.

Has anyone on the list replaced the 3-500z tubes in Heath SB 220, Henry 2K3, Amp Supply LK 500ZA or Drake L4B with a Russian ceramic tube or tubes?

I would appreciate your input and advice based upon your knowledge and experience regarding the subject. Thanks and 73, John, K5PGW