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Tubes for my Mac's 275....NOS or just used?

I am getting close to getting some telefunken tubes for my Mac 275's. I will need 12AX7's and 12AT7's.
What is the difference between NOS and just used? I know there is a saving to buy used but has anyone purchased used with success??

Tks!

Rick (RWD)
rwd
albertporter's avatar
albertporter
4,949 posts
 
NOS is supposed to mean New Old Stock, new meaning zero hours (brand new).

There are tubes that fit this description but not as many as advertised. Many sold as NOS are in fact used tubes. That being said, used tubes that test new are typically low hours, test equipment pulls or test spares. Many of my tubes are used and bought at great prices.

If you want NOS and willing to pay top dollar, Andy Bauman at Vintage can supply them, just be prepared for a long wait. He is meticulous.

As for Ebay, a good many of my hundreds of tubes came from Ebay and generally I've been treated well. Unfortunately you have to know tubes before you can shop Ebay successfully as there are about 20 levels of quality there every day.
ontjesr
157 posts
 
Agree w/Thorman -- if you do not have a tube tester -- stay away from those who sell vintage plates and dolls in addition to tubes (just using an example & have nothing against vintage plates nor dolls).
nsgarch's avatar
nsgarch
2,524 posts
 
Rick, I thought you'd already retubed your 275's. Still running those OEM time bombs? The correct term for used vintage tubes is ANOS (almost new old stock) NOS should be reserved for brand new tubes that at most have only been powered up for testing (but nost sellers are just a little sloppy about that.)

OTOH, really unused, but old tubes, can be uncertain performers. They can have developed leaks, or become gassy (which only shows up after they've be run for awhile) or have internal damage (that causes shorts to happen but maybe not right away.) So sometimes (slightly) used is better -- like with used cables that have already had some break-in. Most of the vintage tubes I've bought have been used, but tested new both for transconductance and remaining life, so I'm not concerned about their performance. Let me put it this way: I've had bad tubes test 'good', but never a good tube test 'bad' ;-)

You don't trust eBay thorman? OK, so what's your point? You either take the time to educate yourself, with or without a mentor's help, so you can buy/bid with confidence or resign yourself to paying at least 3 times more (and up) for the same thing from a tube seller. And you stand a better chance of finding what you want faster on eBay.
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rodman99999
6,206 posts
 
I've purchased the majority of my NOS tubes on eBay, or from eBay contacts over the last 5 years. All the purchases(probably 40+) were excellent, but for one(if you e-mail me, I'll let you know his user name). I got four counterfeit Telefunkens from him. Anyway- The majority of tube sellers on the 'Bay are upright and knowledgable(especially the German ones). You just have to know the right questions to ask to find them. Don't buy anything from those sellers in Asia. they are expert counterfeiters. If you visit here, you'll find a comparison chart that indicates what kind of sound to expect from various 12AX7s: (https://www.tubeworld.com/12ax7.htm) The flavor of the 12AT7s manufactured by the same companys will be similar. If you like transparency, lack of colorations/microphonics, no phoney mid-range warmth: try the Siemens and Telefunkens(from the 60's).
thorman
1,262 posts
 
Nsgarch: It probably wasn't a fair statement about Ebay junk..I have done many good tube deals on Ebay..My point was for a newby or Someone that might seem new to the NOS scene,I think it would be the smart thing to buy first from a relaible ( but more expensive ) tube dealer,thus having a better chance of getting exactly what he might think he is getting..I just think there is a higher percentage of satisfaction that way ..As you did mention.The best thing any potential tube guy can do is " his or her Homework " ...I know we all have put our time in and it does pay off down the road.........
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