New to tubes-what the heck does NOS mean?

I thought it was Never On Sunday. You mean i've been giving them a day of rest all these years for nothing? I guess I have to read the manual again.

Sincerely
I remain

new old stock. the reason that nos tubes, for the most part sound better and last longer is because of the vacuum pulled on the tube in the manufacturing process. because of current high production rates vs nos tubes "they were allowed the time to pull a stronger and longer vacuum".
tim

buy your tubes here, Vintage Tube Services, I found him to be WAY more friendly and helpful than Kevin Deal (at Upscale).

His tubes are just as well tested and he will talk and help.

http://vintagetubeservices.com/

Tim -

there's a lot more to it than how strong of a vacuum was pulled. Cathode coating mix, design, manufacturing skills, many tricks of the trade that are now long lost forever. All of these contribute to the difference between NOS tubes and current manufacture. I was an unbeliever initially until I tried old tubes for the first time. Now I have thousands of them.

-Ed