Are these Mullards?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by traynor_garnet, Jun 23, 2005.


  1. Jun 23, 2005 #1
    traynor_garnet

    traynor_garnet Member

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    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
     
    traynor_garnet, Jun 23, 2005
    traynor_garnet, Jun 23, 2005
    #1
  2. Jun 23, 2005 #2
    Igneous

    Igneous Supporting Member

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    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
     
    Igneous, Jun 23, 2005
    Igneous, Jun 23, 2005
    #2
  3. Jun 23, 2005 #3
    loverocker

    loverocker Member

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    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.
     
    loverocker, Jun 23, 2005
    loverocker, Jun 23, 2005
    #3
  4. Jun 23, 2005 #4
    traynor_garnet

    traynor_garnet Member

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    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
     
    traynor_garnet, Jun 23, 2005
    traynor_garnet, Jun 23, 2005
    #4
  5. Jun 23, 2005 #5
    goneracin

    goneracin Member

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    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
     
    goneracin, Jun 23, 2005
    goneracin, Jun 23, 2005
    #5
  6. Jun 24, 2005 #6
    Blue Strat

    Blue Strat Member

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    Mullards all have production codes (bottom of 2 lines of codes) which begin with "B" for Blackburn.
     
    Blue Strat, Jun 24, 2005
    Blue Strat, Jun 24, 2005
    #6

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