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In Reply to: How many NOS tubes still exist? posted by brobertson on August 11, 2002 at 15:08:04:
More than anyone knows.... hardcore collectors that started buying tube gear for 10 cents a pound in the 70s have enormous collections... I know a guy who has over 300 AMPS! And they all have tubes and four or five (or 12) sets of backup tubes. Suffice to say these are certainties; this is an "angels on the head of a pin question," and it will be a close race as to what disappears 1st, life on earth or NOS tubes.
Follow Ups:
yes, I'd say a shit load, for sure. Just look at what's on EBAY, from a numbers pov.
Hi Chris, This may sound like a silly question, but if a tube made today is stored away for a 100 years would it be classed as NOS, so in theory we would never run out of NOS.
[Badfinger]
You are correct; it is getting to the point where a new term needs to be coined for NOS from the "golden age"-- 1930-1970s era. My mindset is such that I laugh when I see 1980s Tungsram 12AX7s, 1980s East German EL34s and others refered to as NOS... I think the original post specified 1970s vintage. Also all tubes slowly lose vacuum, so perhaps this is another debatable point. Chris
You said 'Also all tubes slowly lose vacuum, so perhaps this is another debatable point.'
So how long does it take to lose vacuum then Chris ? I have 1920's pip-tops which show no signs of going soft , gassy or otherwise and test spot-on as new so it is a 'debatable point' that you actually made . Put your money where your mouth is or otherwise keep it shut . Thank you ! (and please stop making posts with no technical foundation . Guesswork and hearsay comes second place in this world .)
"I have 1920's pip-tops which show no signs of going soft , gassy or otherwise and test spot-on as new"Well, that's about all the scientific proof I need!
How long it takes to lose vacuum depnds primarily on the strength of the vacuum to begin with, the quality of the sealing process, and the amount of residual gas left in the tube.You may notice if you have a large stock of pre-1950's tubes that some getters are becoming smaller and are getting discolored.
You may also notice that pre-1940 tubes are becoming hit and miss. I have several early 45's and 80's that have become gassy over time. There is also the issue of cathode sleepiness in these older tubes.
It is probably true that the majority of tubes with weak vacuum are gone already, by natural selection process.
There is no perfect vacuum, even space is not a perfect vacuum. Consequently, there is no way these tubes will have an infinite shelf life. As to how long, this is indeterminate, as every individual tube will be different. Personally, I'm not greatly worried about my stock in my lifetime. But I wouldn't bank on my 1930's tubes being around in 2030, at least with certainty.
Hi,
Otherwise one starts to see references to russian tubes as "NOS of early production" and such.
I would guess that in a few years time people start to be more specific about russian / chinees tubes like we now are about what runs of 'put in whatever' that are the ones and what are not of the european and american tubes.
Are there evidence (apart from theory) that ALL NOS tubes lose vacuum albeit slowly?If it would take over 100 years for the vacuum-losing process but NOS tubes from the golden age (pre-1970) will be consumed up in the coming 10 to 30 years, there is no point to stress on this possible risk.
Besides, vacuum containers lose vacuum TOO even more readily than NOS tubes! :)
Pack those NOS tubes in a vacuum-sealed container. I started that thought as a joke, but the more I think about it, the more I like it.
Matthew
n.t.
so it really sucks!
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