Help identify this tube?

[Duke]

I found this one in a box at my local radio repair shop. The legible marks on it are as follows.

on one side in order:
OG (rogers logo) in large letters
underneath is "by M (mullard logo)"
ECC83/12AX7
163
B5E5

on the other side:
Made in Great Britain

finally written down the one side:
what appears to be "1022-547"

The obvious is it's a Mullard produced for Rogers, but I'm not sure when this would have been. Any help identifying would be great.

Annoyingly I can't seem to post pics on this thread.

[DaveW]

Here is the coding info. (It is a .pdf format download)

http://frank.pocnet.net/other/Philips/P ... ListAB.pdf

[Duke]

here are some photos.

[morcey2]

According to this page:

http://www.tube-classics.de/TC/Tubes/Va ... /ECC83.htm

the markings 'I63 B5E5' would be from the Blackburn plant between 1959 and 1969. The comment on it is "Quite Rare". If it's still good, it should be a pretty good sounding tube. Nice find.

Either that or it's a pretty good fake.

Matt.

[Duke]

Thanks man, that's a great website. I also figured out that the 'OG' is part of a Bogen label, not Rogers. That makes a bit more sense. The tube tested very strong and sounds good in P2. I have another Mullard that I can't indentify at all that still sounds even better that I keep in P1 (clearer definition on the low and high end). Looking that the two tubes, they appear itdentifcal in structure. Both have a large halo above the plates. Being new to the tube game, I take chances on these as they crop up. But I get them local from a fellow who repairs old tube radios and such and I doubt they are fakes.

[DaveW]

very clear article on dating etc.

http://ozvalveamps.elands.com/valvecodes.htm

[Duke]

very clear article on dating etc.

http://ozvalveamps.elands.com/valvecodes.htm

Thanks Dave. That was very helpful. I have 3 mullard 12ax7s: B6, B7, B8. Now I know what they are and what to look for from now on.