NOS tubes


My question is this, why are NOS tubes percieved/ or not, said to sound better than newly manufactured ones, with all the new technology and manufacturing techniques and materials you would think the opposite to be true, but then again I guess it’s the same as solid state vs. tubes,
Thanks,
Rob
wownflutter
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!