#1
I just went through my old parts drawer and found this tube...
It came from some of my older amps i guess



can anyone identify it?
is it safe plugging it in my amp to see if it works?

edit:
more photos
http://i223.photobucket.com/albums/dd202/Csight/IMG_2393_zps17695edf.jpg
http://i223.photobucket.com/albums/dd202/Csight/IMG_2394_zpsdb868d98.jpg
http://i223.photobucket.com/albums/dd202/Csight/IMG_2395_zps14cc166d.jpg
http://i223.photobucket.com/albums/dd202/Csight/IMG_2397_zps484ef30d.jpg
Last edited by VeilSide at Aug 4, 2014,
#2
Yamaha branded 12AX7. Probably made by one of the various Japanese manufacturers, though most likely Matsushita.
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#3
The insignia on the tube is that of the Yamaha Corporation:



I did not know that they ever re-branded tubes. I say re-branded because I doubt that they actually made it, but I could be wrong.
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#4
Tough to tell from that angle but the short plates and the smooth round spacer on posts make me think Sovtek. I don't think it's a Matsushita, those all had the pointy spacers that went higher up on the tube IIRC. Does it have a country of origin printed on it anywhere?

No harm in tossing it in your preamp to see if it works.
#5
Looks cool man. Can't make out what's printed after the 12AX7A (which is different than a 12AX7 mentioned above). 12AX7As are much quieter than a 12AX7. I'd pop it in and try it out

I want to say it's a 7025 which were manufactured for military use (although the last number doesn't really look like a 5), and are supposed to be the quietest of the bunch and should offer some clearer, louder tones. I'm pretty sure they were used in the Blackfaces back in the 60s.

I could be wrong on all that. I've seriously never heard of a Yamaha branded tube. I'm just reading the label on this one

EDIT: Tried googling 7023 and just got a bunch of people misreading their tubes. Could be what I keep doing every time I look at that pic lol
Last edited by mjones1992 at Aug 4, 2014,
#6
Quote by mjones1992
Looks cool man. Can't make out what's printed after the 12AX7A (which is different than a 12AX7 mentioned above). 12AX7As are much quieter than a 12AX7. I'd pop it in and try it out

I want to say it's a 7025 which were manufactured for military use (although the last number doesn't really look like a 5), and are supposed to be the quietest of the bunch and should offer some clearer, louder tones. I'm pretty sure they were used in the Blackfaces back in the 60s.

I could be wrong on all that. I've seriously never heard of a Yamaha branded tube. I'm just reading the label on this one

EDIT: Tried googling 7023 and just got a bunch of people misreading their tubes. Could be what I keep doing every time I look at that pic lol


just to clarify for TS: the 12ax7a's and the 7025's were just low noise 12ax7's. they weren't actually quieter (they have the same gain factor as a 12ax7) so much as they had a more favorable signal to noise ratio.
punk isn't dead, it's always smelled that way.

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#7
And these days the A normally just means that it's a 7th generation Shuguang. ie. garbage.

If you took a photo where we can see the internals better we'd have a better chance of identifying it. All we can tell from that photo is that Yamaha have stuck their logo on a tube.
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#9
What an odd one. It doesn't look like Matsushita, Toshiba, Hitachi or Raytheon. Those are the main MIJ tubes I know of. Sorry I can't help more, but that's just weird.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#10
Quote by Cathbard
What an odd one. It doesn't look like Matsushita, Toshiba, Hitachi or Raytheon. Those are the main MIJ tubes I know of. Sorry I can't help more, but that's just weird.


It's a Shuguang based on the plate. Didn't know Yamaha were using tubes that late.
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#11
I did think it looked quite Chinese. If it's an old Chinese valve then it will be a piece of crap, sorry.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#13
i tried to put that in V1 instead of the RFT thats in there...
i should say the RFT went back pretty fast
#14
Quote by gumbilicious
just to clarify for TS: the 12ax7a's and the 7025's were just low noise 12ax7's. they weren't actually quieter (they have the same gain factor as a 12ax7) so much as they had a more favorable signal to noise ratio.


My bad. Should have worded that better Thanks for clarifying.