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Help with Identifying 12AX7s

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AbaddonD

Member
Joined 2015
#1
Hi!

So a few months back I got an old Ahuja HRC-32T tube amp with 2 EL84s in class AB and the seller told me that it has 3 ECC83 (12AX7) in it.

Well, the labels have come off and 2 of them seem similar while the other one looks a bit different.

Can anyone help identify these tubes? If they are 12AX7 or not and the manufacturer.

The 2 similar ones have filament flash, their plates are shorter than the other one, and they have circular (not oval) holes on each sides of the plates while the other one has no holes. Also, the 2 similar tubes are a tiny bit (1-2mm) shorter than the other one, but that could just be a tolerance thing.

I have attached the pictures of the tubes down below.

Thanks everyone!
20200326_171059.jpg

20200326_170937.jpg

20200326_171200.jpg

20200326_171242.jpg

P.S. Sorry about the upside down pictures. They were fine on my phone, don't know what happened.
 
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#2
As I don't recognize any etch code on any fo your tubes, these ECC83's (not 12AX7's) could have been made by any European manufacturer. I own a considerable collection of pulled, old ECC83's of different provenience. They all look very similar. And they all look very similar to most of my European ECC82's. So be careful, as both can be discerned reliably only by measurements.
Best regards!
 
#3
Kay Pirinha said:
As I don't recognize any etch code on any fo your tubes, these ECC83's (not 12AX7's) could have been made by any European manufacturer. I own a considerable collection of pulled, old ECC83's of different provenience. They all look very similar. And they all look very similar to most of my European ECC82's. So be careful, as both can be discerned reliably only by measurements.
Best regards!
Click to expand...

Yes, there are no etched codes on them, except the crude "A" and "B" lightly carved on the 2 triode sections of the long plate one.
 
#4
AbaddonD said:
Yes, there are no etched codes on them, except the crude "A" and "B" lightly carved on the 2 triode sections of the long plate one.
Click to expand...

I was looking through some of my CV4024 tubes. I bought a job lot, and it is mixed production from Brimar and Mullard. I noticed that some of these have etched letters on the plates - does anyone know at what stage in production these were added, and if they have any significance?

I'll see if I can rustle up a pcture later ...
 
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