NOS Tubes 12AX7

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thomascsmits
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Re: NOS Tubes 12AX7

Post by thomascsmits » Fri Aug 19, 2011 3:35 am

Found 2 old philips/miniwatt ECC83's in a radio which I bought fr 10 euro's on a flea market. They turned out to be relabelled mullards which was a nice supprise. They sound fantastic in just about every amp I've put them in, the new tubes just sound lifeless compared to them.

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AustinTx
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Re: NOS Tubes 12AX7

Post by AustinTx » Sun Oct 09, 2011 7:45 pm

Tested 72 12ax7s today, 63 used old production & 9 unused new production

New production = 1 gold Lion / 1 sovtec / 1 EH / 5 JJ higain from eurotubes / 1 JJ

JJ from erotubes tested the best of the new production
used the specs from the strongest new production tube for comparison

61 of the 63 used old production tubes tested better than the best new production tube
some by a little and some by a lot....some of the used tubes looked pretty used up
and they still beat the new production specs. Didn't have time to test for microphonics,
i am sure some of the oldies will be microphonic and get tossed...always a few that test well
and are no good in a cranked up amp..

Old Baldwin, Thomas and Hammond organ branded tubes that you can get on ebay for $5 to $10
still sound better and last longer than new production tubes. Some folks still get pissed at me for
posting info about the poor quality of new preamp tubes...somebody please prove me wrong,
i want new preamp tubes to great!
Austin Texas
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Joshabr1
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Re: NOS Tubes 12AX7

Post by Joshabr1 » Tue Sep 23, 2014 2:01 pm

I'm sure it's been covered but I am loving a Raytheon black plate(long) in v1&2 and a rft in v3. Great clarity smoothness and nastiness at the same time.

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novosibir
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Re: NOS Tubes 12AX7

Post by novosibir » Tue Sep 23, 2014 7:59 pm

AustinTx wrote:(...)
61 of the 63 used old production tubes tested better than the best new production tube
some by a little and some by a lot....some of the used tubes looked pretty used up
and they still beat the new production specs. (...)

(...)...somebody please prove me wrong
Sorry, but I have to prove you right :what: :mrgreen:

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Re: NOS Tubes 12AX7

Post by Haze13 » Thu Sep 25, 2014 11:43 am

I read all the time that the materials (alloys) for the metal parts of the tube (plates, cathodes, screens...) were different and better then what being used nowadays, and that they are not healthy for human. Well in the 21 century there are more toxic things that are being used in the manufacturing process all over the world than in those tubes... So is it truly that only the alloys that different? Well 6973 pentode from EH looks not like the old one. 12ax7 from Mullard (Reflector will be more correct I suppose...) look different too...
May be there are other things than just the quality of the components?

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novosibir
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Re: NOS Tubes 12AX7

Post by novosibir » Thu Sep 25, 2014 12:04 pm

Haze13 wrote:May be there are other things than just the quality of the components?
The barium & strontium oxide, what was used for cathode coating in the old days is radioactive and hence no longer allowed in production. But more then this the chemicals, which were used (had to be used) for preparing the cathode pipe before coating in the past were so extremely toxic, that they even not in China are still allowed.

Larry
The fault almost always is sitting in front of the amp :wink:

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Haze13
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Re: NOS Tubes 12AX7

Post by Haze13 » Thu Sep 25, 2014 12:15 pm

Well... I am from the city where Atomic Submarines are being manufactured, and I heard of these chemicals to much:) (Actually now I live in the other country...)
But, that explains why the Valves can stand the radiation!

Teleman76
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Re: NOS Tubes 12AX7

Post by Teleman76 » Mon Dec 14, 2015 5:07 pm

Raytheon long black plates. I'm buying them up so I'll always have some around.

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