Can't do that in this case, plus there are only very few tube mfgs left
What's that matter? The surplus supply is still well stocked. No need to use exclusively JAN-CHS 6AK5-ABCXYZ's either. 6AU6, 6BA6, 6DK6, 6DJ8 (well, not a pentode, but often used in RF anyways), 12AT7, 6BQ7, the list goes on for ages. And equivalents, and similar or equivalent European and Russian types.
Assuming you were going to use a tube, what is it about not-current-production types that matters so much? Are you making ten thousand of these things? Now I want to know...
Tim
-- Deep Fryer: A very philosophical monk. Website @
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