|John Stokes||Re: JJ/Tesla ECC83/12AX7 tubes in PJ?|
Lee, microphonics susceptability is a known problem with the Ei 12AX7. I would hazard a guess that most of them are too micorphonic to use in a gain amp. However, not ALL of them are excessively microphonic. I bought a bunch of them from LV that he pre-tested for microphonics, and every one he shipped me is usable. Yeah, I paid him a bit more for this screening, but the result is I got a whole load of tubes and every one is good. When I previously would buy the things, I'd end up with at least a 50% reject rate. So I just decided to pay more and get examples that were known-good. If you are looking for a sweet and warm sounding 12AX7, the Ei is the ticket, if you can get one of the few that doesn't ring like the telephone. Snap them up while you can, I heard the factory was flattened in the NATO bombing of Serbia since the same factory also made tubes used in Serb radars.