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Old 22nd February 2013, 03:22 AM   #1
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Default Help Identifying a Tube - Westinghouse 12AX7A

I recently bought an amp and it had Westinghouse 12AX7As in it. I've been trying to find some reliable information on them and it is a little hard to come by. I have a suspicion that they might be rebranded knockoffs, but there is a very similar looking one on eBay for quite a lot of money. Any insight into these tubes would be appreciated.

http://www.flickr.com/photos/isadore1/8495718987/
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Old 22nd February 2013, 05:36 AM   #2
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They look genuine. Made in Germany is generally good. I would keep them rather than sell. Also sometimes people list things on eBay for outrageous prices hoping someone will bite. If they test good I'd run them.
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Old 22nd February 2013, 05:42 AM   #3
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Those are Chinese preamps man unmistakable plate structure, shuguang 9th gens most likely that shiny silver shield on side of plate its a dead give away.
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Old 22nd February 2013, 10:10 AM   #4
DF96 is offline DF96  England
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Yes, genuine Chinese. The screen/shield says it.
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Old 22nd February 2013, 05:01 PM   #5
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Wondering why the Chinese put that shield there.
I don't know any other ECC83/12AX7 with a construction like that.
Considering that they are copyists, they must have had some inspiration (example)?
The ECC808 is like an ECC83 with a shield, but not one that wraps around the plates.
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Old 22nd February 2013, 06:15 PM   #6
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the Chinese examples are copies of 6n2p whit changed heater connections.
the first chinese tube factories where set up whit western help, the later whit russian technology.

the 6n2p is a noval replacement for the octal 6sl7 in Newly designed equiptment.

the chinese 12ax7 will have comparable gain to a 6n2p:80 instead of 100

Midnightmayhem: They look genuine. Made in Germany is generally good. I would keep them rather than sell. Also sometimes people list things on eBay for outrageous prices hoping someone will bite. If they test good I'd run them.

you sir, made me laugh my *** off

except for the diamond marks, and Fat bulbs slim short plates(RFT) http://www.tubemongerlib.com/gallery...st+Germany.jpg

here's a nice rule of thumb, if the inside connections are copper, its made by communists

Last edited by v4lve lover; 22nd February 2013 at 06:19 PM.
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Old 22nd February 2013, 07:43 PM   #7
DF96 is offline DF96  England
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Quote:
here's a nice rule of thumb, if the inside connections are copper, its made by communists
Interesting. I have not thought of that before. Did they have better accesss to copper than the nickel alloys used in the West?
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Old 23rd February 2013, 07:29 AM   #8
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Quote:
Originally Posted by v4lve lover View Post
except for the diamond marks, and Fat bulbs slim short plates(RFT) http://www.tubemongerlib.com/gallery...st+Germany.jpg

here's a nice rule of thumb, if the inside connections are copper, its made by communists
RFT is East German, right? So communist as well.
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Old 23rd February 2013, 10:05 AM   #9
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Okay maybe someone more knowledgeable than me can shed some light on the difference between the As and Bs Chinese/Shuguangs 12AX7s?. I have some that are labeled the Bs and they have this badass mid range grind like no other, really gainy more so than my JJecc83. I think the Bs are 9th gen designated and I have read and heard the As were 8th gen, is really any difference at all? and I seen there is actually a C version is it even more gainy?
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Old 23rd February 2013, 03:33 PM   #10
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Quote:
Originally Posted by Parafeed813 View Post
RFT is East German, right? So communist as well.
exactly.
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