Tube ID

[thetruthisgood]

Hello
Could anyone tell me about these tubes?

Two tubes were sold as NOS Sylvania 12AX7. One of them (1st in pix) had flecks of green labelling and also '12AX7 WA' in white.

The other (was 3rd in the list) was labelled:
(in orange)
Amperex
12AX7A
ECC83 (then something faded, apparently the numbers '138')
MADE IN GT BRITAIN
(then in upside-down white writing)
I63 (the letter I, not 1)
B6G2
**the tube box was labelled 'Amperex / A North American Philips Company / 12AX7A ECC83'

Any tube lore to tell?

III

[danman]

Hello, your first tube is definitely a Sylvania 12ax7...nice tubes and most of mine test quite a bit higher than some of the other brands I own. Your second tube I am not sure about yet...I would have to check my spares to see if I can find anything similar. The third tube is actually a Mullard ECC83, manufactured 2nd week of July, 1976. The code on the base starting with "b" is the Mullard Blackburn factory code. You will usually find Amperex tubes to be manufactured in Holland by the Phillips Corporation (which also owned Mullard) but it was not uncommon for them to rebrand other manufacturers tubes also when supplies ran short. Amperex was simply a North America distributor for Phillips tubes. In Europe the same tubes would have been sold under another name such as "Miniwatt". Providing your tubes test good you should have yourself some very nice tubes!

[thetruthisgood]

Cool, nice. Any others?