I agree with Elizabeth. I've had occasion to test a considerable number of 50, 60, and 70 year old NOS tubes, on a Hickok dynamic mutual conductance tester, and they have tested as I would expect a new tube to test.
Also, the prices some audiophiles are paying for certain tubes of that period would seem to provide added confirmation.
Regards,
-- Al
Also, the prices some audiophiles are paying for certain tubes of that period would seem to provide added confirmation.
Regards,
-- Al