Buying tubes...do they vary???

@mr_m , you’ve brought up an interesting subject. I like to deal with Andy of VTS not only for his high quality tubes and advice, but also to hear about his experiences in the electronics/tube world. He once told me about after WW II and Korea, the techies would grab all the tubes they could gather and ship them home. The tubes came from radio installations and anywhere electronics were used; that includes the enemy and the Allied forces supplies. Tubes were even scooped up from the battlefield.
I once ordered a rare Amperex tube from Andy, he only had one and said he would look for it on the top shelf of an area he hasn’t used for a while. I received the order and the box was dirty, faded, and tattered, just like it had been through a war. The tube inside was perfect and had incredible low noise.

There is a vast supply of those old tubes out there that never saw daylight outside the boxes they were put in.

Think of all the different scenarios where tubes may have come from.

But, I agree with @elizabeth that there are many, many tubes being sold as NOS that were lightly used and taken from electronic devices. If they test well, they are called new old stock. It’s funny how many NOS tubes come in a generic white box.

Love it when a post takes off! Thanks all for the wonderful responses!

lowrider57 and elizabeth. While I believe there are a lot of true NOS tubes out there, I agree that a lot of those tubes peddled as never used is quite likely fraudulent. Or at the very least the seller isn't quite sure of usage. They can say the tube measures strong, but I believe a tube's microphonics and noise levels are at least a probable indicator of much usage or lack there of. IMO.

I agree with the poster who stated that NOS really means the tubes test well or test “like new.” The designation NOS is not (rpt not) supposed to mean brand new nor does anyone who buys NOS tubes expect brand new tubes. I would obtain NOS military grade 12AX7WA (Sylvania and RCA) from a friend of mine who worked in tech at NASA back in the 70s and while the tubes had been used previously they were spectacular. Caveat emptor. Don’t be hornswaggled. You have to do due diligence. There are lots of deals out there the last time I looked about three years ago. I did quite well on eBay for some hard to find expensive type NOS tubes like Sylvania Bad Boys. But you really need to do due diligence since some tubes advertised as Bad Boys aren’t really Bad Boys, but are very close. And when you find the tubes of your dreams be sure and check out Herbies tube dampers and contact enhancer for the tube pins.

NOS tubes come in white boxes because most tubes were bought in bulk by manufacturers or large scale users of electronic equipment. They came in boxes of 100 or maybe even 500. Individually boxed tubes were a smaller piece of the market.

There are still new tubes around, a lot of them actually, but a lot of tubes sold as NOS are not.