Are these Mullards?

[traynor_garnet]

I've been going through some old 12ax7s and trying to see what I actually have. Can anyone give me some info if these are mullards or what they are . . .?

1.) Rogers 12ax7a
Writing is blurred and cannot make out where it was made.
Has the code I (7?) 65 r4BI on the side.

2.) Ge 12AX7A/7025
Made in Japan
Code = A5 JX

3.) Marconi 12AX7A
Made in Japan
Code = PN

Any help would be great. I was thinking of buying some Mullard 12ax7s and thought I should first see what I already have.

Steve

 

[Igneous]

these all sound like maybe not. The true way(if you own any) is just to look at the construction itself. Any pics would likely help.

Look for telltale signs(copper grid posts, strong construction, )

although not all have copper posts. Im pretty sure i can tell you if you send a pic.

fwiw- recently picked up a NOS mullard old logo on ebaY for 69.95 -that is a decent price for new. If youve never had a mullard ax7 why not start at a good reference point and get a new one. That way it doesnt give you a bad im,pression if you get a so-so one.

-Latas-Ig

 

[loverocker]

For safety's sake, I'd look for the 2nd etched code starting with a 'B' (for Blackburn). This weeds out valves that Mullard bought in from elsewhere and added their logo to.

 

[traynor_garnet]

Originally posted by Igneous
these all sound like maybe not. The true way(if you own any) is just to look at the construction itself. Any pics would likely help.

Look for telltale signs(copper grid posts, strong construction, )

although not all have copper posts. Im pretty sure i can tell you if you send a pic.

-Latas-Ig

How do you post pics here? I could take some pics but don't really know how to upload them to the board.

My technical knowledge is too weak to examine the tubes' construction and determine their manufacturer.

Steve

 

[goneracin]

The first tube, the Rogers with the r4b1 code is not, its a canadian made amperex, same construction supposedly as the holland amperex, but they sound a touch different to me, and are not as durable.
Im wondering if the other 2, if they look like mullards are matsushita made. They could also be one of several other japanese manufacturers ,raytheon had some tubes made in japan. Probably not mullard however, at least not the tradititional mullards, which were made in England.
Bob

 

[Blue Strat]

Mullards all have production codes (bottom of 2 lines of codes) which begin with "B" for Blackburn.