New to tubes-what the heck does NOS mean?


I checked 50 posts in the forum and saw many references to "NOS" but didn't see what it stands for. Tell me please?
Also, any opinions on good values in EL34 tubes? I've read some good things about EH (Electro-Harmonix) being a good output tube VALUE. Your comments based on actual listening experiences are appreciated.
Thanks and happy listening!
myraj
New OLD Stock . . Vintage or old tubes of suposed higher quality. If you are willing to spend a litle more contact kevin @upscaleaudio.com He will sell you the best thoroughly tested tubes . He is not the cheapest but one of the best .
NOS stands for "new, old stock" The tubes have never been used but they are not newly made (read: not as good). Some people prefer tubes from a certain manufacturer and from a certain time range rather than brand new, just made tubes. Personally I prefer Krell tubes.
NOS means new old stock: new tubes produced mostly 30 to 40 years ago (before the transistor-age).