Newbies to the audio world encounter a lot of puzzling terminology, some of which seems oxymoronic. One such term that took me a while to understand is NOS---New Old Stock. If you parse the phrase out in segments, it actually makes sense...at least, more sense than "jumbo shrimp" or "military intelligence".
Okay: think of "new" as meaning "unused", not, "just made". "Old stock" is pretty much self-evident; think of a general store that's gone out of business after 100 years. Odds are, there will be merchandise that's been on the shelves for a long while, that just never sold: Big Chief tablets marked 5 cents, Wrangler jeans with button flies, crank-style egg-beaters. You get the idea: you've likely seen truckloads of such stuff at flea markets or on eBay. So: NOS means products made some time ago, but unused, likely never sold. Capiche?
I know it's hard to believe, but a lot of folks in the audio and electronics fields are...HOARDERS. I've seen radio and TV repair guys who picked up anything they thought might be useful someday, any time a colleague died or retired. Often times, the goods aren't even related to the gear they usually work on, but are picked up as material for future trades. I've also been to estate sales of audiophiles and ham operators where the surviving family members just had to move 20 cubic yards of stuff. Those are the times that try an audio geek's soul: do I pay a nickel a ton, or do I try to help the family get what this stuff is really worth?
Over the last 40 years, I've done both. And there are some actions that shame me in my memory: I'll do better next time. I hope.
It's not often that a longtime audio dealer goes out of business and you encounter a bunch of now-very-expensive collectable tonearms MIB (mint in box, a term stolen from the world of toy collectors), but it has happened, even to me. More often than not, if you see the term NOS applied to audio gear, it's going to be applied to vacuum tubes---valves, if you're east of the pond.
The last 30 years have seen a major resurgence in the production of new tubes worldwide, but before that happened, there was a generalized panicky sense that tubes would be unavailable, and that whatever tubes were still being made, were junk. That impression was furthered by inferior-grade tubes that mimicked the construction and appearance, down to the packaging, of better-quality tubes from the US, UK, Netherlands, Japan, and Russia. Even recent Chinese and Russian tubes of passable quality were faked, in some cases by scraping off the original silk-screened markings on the glass envelope of the tube, and forging the marks of a more-desirable tube.
Frankly, I think there are easier ways to make a buck. Oh, well.
The result of this mania was to create a halo effect around NOS tubes, the sense that old was always better. Let's be real here: just as there were junky brands of electronics or speakers made in the past, there were tubes that were lesser-grade. It's unrealistic to assume that everything olden is golden---right?
And yet, many of those old tubes were sold at premium prices. They may have been used a bit, for all we know, they may have been gassy (meaning the vacuum was breached, and air has made its way into the tube), they may have been used in a guitar amp by a traveling musician, and have elements just barely hanging together. Such was the mystique of NOS.
These days there's a fair variety of new, high-quality tubes being made. There are also well-established dealers who can properly grade and match old tubes so that you can be sure that you get what you pay for.
I don't doubt that certain old tubes have irreproducible magical qualities. I pulled enough unused Western Electric tubes out of old theaters to catch a little bit of the fever. But I'd be more excited to find an old 16" Presto or Fairchild broadcast turntable new in a crate, stashed, forgotten, in a small-town warehouse. But to go ape over dirty, untested tubes simply because they're old, is naive.
To me, the most exciting use of NOS tubes, speakers, whatever, are when those elements are used by mad scientists like Vu Hoang (check his work in the Tampa show report), jc morrison, Jeffrey Jackson and Dave Slagle, or Jonathan Weiss to create something familiar, but transcendently different and new. In my mind, that's the best of both worlds.
But then: different strokes, right?