NOS tubes

To answer the OP's question.  And I'm talking about preamp tubes not power tubes.  Tube quality was very important back before transistors replaced tubes,  when tubes were used in essential functions in airplanes, radar, early computers, television broadcasting, medical equipment, etc.

They are getting better at making tubes but the really good ones often cost as much as NOS.  You would think that eventually they will make tubes that sound better than NOS with the technology available today, and I think they probably will, but for now I prefer old stock to the new production tubes I've had in my system.

Tim deParavicini (EAR-Yoshino) told me old tubes are better because the people making them did so as a career, with a lot of experience under their belts before they were promoted to the position of making them. To the people making them today, doing so is just a job for now---they are not experts in the field, as were the old-timers. He told me he prefers old Mullards, which may be partly because he is British.

Vacuum Tube Valley had a report on this. Look it up! It seems that the cathode-coating chemicals were of a much purer quality. Vacuum pumping went on longer, resulting in a better vacuum. Grid wire spacing was held to tighter tolerances.      Speaking from my experience as a longtime tube user I prefer using vintage used tubes that still test GOOD over present day production!

+1 bdp24!

+2 bdp24!