Could someone explain what NOS tubes are, what NOS stands for and why they are desirable and also how to know among the various brands which are of the highest quality?

Thanks

NOS stands for new-old stock and refers to tubes that were manufactured perhaps years ago, may not currently be production, and have never been used (hence the 'new' part).

can also stand for- NEW tube with -OLD- STICKER. there are fakes out there. best to deal with known reputable tube stores and dealers.

The conventional wisdom is that there was a golden era of tube production that has ended and that new tubes are bad and old tubes are good. While true to some extent I suspect some marketing hype in the whole NOS market and vintage gear in general...there are some great sounding old tubes, though...

Mike

Were vacuum tubes ever used for any other purpose besides music?

Is there indeed a vacuum inside the tubes?

have you ever seen a big ass TV that wont stick to a wall.
thats a vacuum tube. in some counties they have a switch on the side
of the wall that turns on a tube . I use mine so I don't trip over shit when its dark.

I think a TV has negative 15 PSI?

they were also used in early, punch-card style computers.

Shit, I was bummed when I had to buy 9 tubes for my JCM800. I would hate to retube that thing. WHeew


Neil

New Old stock...


>Were vacuum tubes ever used for any other purpose besides music?

Is there indeed a vacuum inside the tubes?


Like all electronics in the past... there used to be 100s of tube manufacturers.. radio, TVs ancient computers (before PC used too) all existed. Basically tube existed before solid state did. There used to be tons of manufacturers of tubes in the U.S and Europe. Now China, and Russia are the only places that make tubes... and really three factories... between them make most of your common tubes like Ecc83/12ax7s.

Best tubes? Amperex Matched Pairs of 12AX7as NOS is about 150$ a piece... Holland made. tightens up bass on a guitar amp niceley

more reasonably price... NOS American tubes from RCA and phillips made by various factories or Mullards (UK made) run 15- 30$ per tube.

My experience with tubes is mostly guitar amps, but I actually have all of these.

Prior to the mass production of transistors, all diodes, triodes etc used glass bottles and cathode rays to perform the range of functions that has since been achieved with semiconductors (eg silicon). So a vast range of electrical and electronic appliances - including switching systems, data systems, transmission systems and audio systems depended heavily on tubes. Arguably even incandescent light bulbs are also a form of tube (though we don't generally call them that...).

In fact music was only a small sub-set even of the audio part of the electronics industruy in the era of tubes - and most of the music part of the market was radios and gramophones - musical instrument amps and recording equipment represented an even smaller fraction of the market.

FWIW, in the 1960s, you could rip the receiver out of an old broken radio and use the remains as a tube guitar amp (if you didn't mind carting around the clunky walnut veneered boxes they came in).

After a fashion. In most cases it is not a complete vacuum, but most of the air is evacuated - in fact some valves (eg triodes) depend in part on ionisation of the remaining gas. One of the significant things that contributes to the different sound of otherwise identical tubes (even from the same manufacturer and the same batch) is slight variations in the quantity and composition of the gas remaining trapped inside the glass.

You don't necessarily have to find NOS tubes. Many old home stereos and plenty of
old military gear used tubes that will still test good if you take them down to an old
TV or audio repair shop.

So if you like to browse around at garage and estate sales, or GSA auctions you can find very high quality tubes for pennies on the dollar.
An example of a hot item might be an old Grundig or other european made
stereo that used Telefunken, Amperex, Mullard or USA brands RCA, or Phillips.

If you look at the particular makes and model designations at some of the NOS tube
supply stores, you'll get a good idea of what to hunt for.
Then narrow down your hunt for guitar amp related tubes.

12AX7A, 12AU7A, 6L6, 6V6, 6550, EL34, EL84, 5881, KT88, KT66 and so on.

As mentioned above some of these tubes are worth up to $250.00 EACH if they
test good.

The tube stores are also handy as a guide for learning the particular characteristics
of each tube as far as clean headroom or breakup factors.

Your hunt for audio tubes can also lead you to a virtual treasure trove of class A amplifiers.

Military spec gear also presents you with a possible killing on what you can get for your money.

Many of those old military spec components used all GOLD connectors.

A while back, I talked to an electronics liquidator.

They bid $800.00 on two crates of military spec components at a local GSA auction.
They ended up with $11,000.00 worth of gold from those components.

As mentioned in my Trash or Treasure thread, just this week, I found a rack of
perfectly good Mullard pre-amp tubes in an old POS Univox amp head.

The 12AX7A and 12AU7A tubes are probably worth about $40.00 each and I'll certainly put them to good use.

Yeah but how does it SOUND? I'm glad I don't have to do cross-fades on this thing!

That's where the NOS tube store guides come in handy.

Such as

http://www.tubesandmore.com/

Please do not attempt to respond to electronics-related questions if you are not even able to differentiate between "silicone" (a synthetic product used for everything from lubricants to breast implants) and "silicon" (an element from column IV of the periodic table which in crystalline form and is the foundation for the electronics industry.

Action


[QUOTE=DarkSky;1297665]Prior to the mass production of transistors, all diodes, triodes etc used glass bottles and cathode rays to perform the range of functions that has since been achieved with semiconductors (eg silicone).

If you are new to NOS you'll want to spend some money at first to be sure you're really getting a good tube, then learn over time what each brands strenghts are, and eventually shop on your own power, after a few years of this A/B approach using real NOS. If you're smart about NOS you can do well (read: good deals) on Ebay, but this is harder. You will probably get burned a few times as there are some junk tubes on Ebay as well.

www.tubeworld.com - not cheap but reputable
Upscale Audio - Rare Tubes - same

NOS is not dogmatic snobbery, there are some new tubes for guitar amps that are 'good enough' for power tube apps and the occasionally Sovtek or JJ could be just the dirt you need, but for a more open tone that has some real beauty NOS wins most of the time. RCA Black Plates, pre-70s Mullard, Telefunken, Amperex Bugle Boy, even Sylvania for a clean tone, etc. ... each of these has a color that can be useful in a chain.

I have a 22 tube eq and each section uses a different brand in a low noise, matched pair based on that brand's strength (Mullard- Hi Mid boosts, RCA - Low Mids, Telefunken - Hi Shelf, Amperex EF86 Output Gain, etc) ... the difference between this and the stock, select Russian tubes was clear. I paid no more than $25 per tube on Ebay, but that's after 20 years of using tubes. Best to pony up to the dealers that can educate you.

Some more worthwhile information here.

http://www.vacuumtubes.com/

LOL. Thanks for catching that.

And might I add... Please do not attempt to respond to semantics-related issues if you are not even able to differentiate between "silicone" (a synthetic product used for everything from lubricants to breast implants) and a typographical error.

Well we know where your mind was anyway

Must have been one of those Freudian slips.

the other reason for NOS tubes, besides a bias (pun intended) for 'vintage' tubes, is that some tube models are not manufactured today. therefore, in order to get replacement tubes you either have to modify your equipment or buy new-old-stock tubes (or, you could buy used tubes which have an ambiguous amount of life left in them).

this problem seems to have waned a bit in the last several years as manufacturers (electro harmonix, tesla, etc ...) are making more tube varieties including several models that had previously been out-of-production or otherwise unavailable or hard to find.

A"normal" vacuum tube is totally evacuated. As much as possible. I do not refer to tubes with gas. It is a tedious process to pump all air out. Therefore they use that shiny stuff called "Getter". It is a kind of metal powder that deposits on the tube glass when the tube is heated in the manufacturing process. The metal absorbs the remaining (almost) air residues. A TV Cathode Ray Tube (CRT) (youtube still got the CRT in its name) is pumped down as far as it is possible with respect to the production process. If a CRT leaks a little, it is sometimes possible to see a glow inside. That is NOT supposed to be there! Sorry, that tube has to go to the recycling center...
Tubes were used for communication radios, oscilloscopes, multi-meters, radio and TV transmitters (still do) and all kind of stuff before the transistors came. High power transmitters for very high frequencies are still not transistorized.