Trying to identify this 12AX7 tube

50MkII

Member
Messages
344
Hey Thom-

Thanks but it does read "12AX7A" and I can make out a "T" followed by a space and "BRITAIN" all lettering in yellow. The lettering before the "T" is rubbed off.

That Hitachi tube looks similar, but the halo getter on mine is raised higher than that one. Without more pics of that Hitachi it's hard to give you more info but the plates look similar except maybe the top of the plates connecting the mica is a duplicate of the bottom unlike that Hitachi where the top is missing the same connector to hold the plate in to the mica, if that makes sense.
 

Timbre Wolf

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I would not hold too tightly to the "Britain" paint job... Lots of tubes that originated elsewhere (Russia, Hungary, and others) have also been labeled with Britain or England.

- T
 

50MkII

Member
Messages
344
Interesting. As a guitarist, what should one watch for when these things pop up (anything in particular that gives it away)?

Sounds like this might confound anyone id'ing tubes.
 

Timbre Wolf

Hyperspatial Gravity Surfer
Platinum Supporting Member
Messages
9,987
It takes experience, training one's eye for minute details - and caring about things that most people would rather not make the effort to learn. There is a bit of deductive reasoning involved, too.

I could be wrong about the Hitachi origin. But the other piece is that the tube does not look like it was made in Britain. GEC made 12AX7, but stopped way before the 12AX7A was first produced. That leaves Mullard and Brimar, and that tube does not look like either. So that leaves another country of origin... Behold, the tube looks like other Hitachi tubes. But it still may not be...

The best advice I can give is to learn to look inside the tubes for clues to true origin. Tubemonger.com is a good place to start, since they've got their photo library. Study the details of construction (which you're already doing), and look to the paint only as a secondary clue.

- T
 




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