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    Tung Sol Black Glass 12AU7 square getter

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    simonfck

    Posts : 15
    Join date : 2013-03-04

    Tung Sol Black Glass 12AU7 square getter

    Post by simonfck on Wed Aug 21, 2013 4:41 pm

    Very strong Bass. Sweet natural vocals, graceful and  transparent.
    Nice tube for the money.

    just Don't know what year.





    ts 12au7 1



    ts 12au7 2



    ts 12au7 3


    peterh

    Posts : 679
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by peterh on Wed Aug 21, 2013 4:49 pm

    simonfck wrote:Very strong Bass. Sweet natural vocals, graceful and  transparent.
    Nice tube for the money.

    just Don't know what year.







    ts 12au7 1



    ts 12au7 2



    ts 12au7 3

    What's the point with this post ????

    simonfck

    Posts : 15
    Join date : 2013-03-04

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by simonfck on Wed Aug 21, 2013 8:51 pm

    I did some tubes rolling with VTA70
    I have Jensen PIO coupling capacitors, some tubes too soft for me.

    Mullard long plate square getter. Mullard 10M They are rich and warm smooth and detailed. But too much money, still love it.

    60s Amperex  Bugle boys D getter too bright
    GE JG 581A too much Bass
    Brimar 13D5 too bright
    RCA Clear Top  warm,but less detail.
    Tung Sol Black Glass well balanced

    sKiZo

    Posts : 1308
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by sKiZo on Thu Aug 22, 2013 1:28 am

    Date codes can be fun ... in this case, I do know that "322" is the TungSol manufacturer code, but that would usually be followed with four digits for year and week.

    Just to complicate things, they did occasionally use an alternate code string that dropped the first digit of the year. So that leaves us with "2". Most expect the single digit date code to designate the 1940's ... but wait ... the 12AU7 didn't show up in the tube registry till 1946. So ... the earliest production date based on that information would be ... (drumroll please) ... August, 1952.

    That was fun ... and maybe even right! tongue 

    The reason I say that is, the same alternate date code was used by some companies into the 1970's ... don't know about TungSol specifically ...

    Then again, I see some hints that they only did the black glass up thru the 1950's ... probably too many plant workers glowing in the dark due to the manufacturing process ...

    And, if you can find one with "JTL" preceeding the code, that's the military version and commands a premium price.

    Either way, one fine tube there ... consensus is smooooooooth ... only complaint is they tend to be a bit microphonic, so you may want to think about damping it if that's a problem.

    simonfck

    Posts : 15
    Join date : 2013-03-04

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by simonfck on Thu Aug 22, 2013 1:59 am

    sKiZo wrote:Date codes can be fun ... in this case, I do know that "322" is the TungSol manufacturer code, but that would usually be followed with four digits for year and week.

    Just to complicate things, they did occasionally use an alternate code string that dropped the first digit of the year. So that leaves us with "2". Most expect the single digit date code to designate the 1940's ... but wait ... the 12AU7 didn't show up in the tube registry till 1946. So ... the earliest production date based on that information would be ... (drumroll please) ... August, 1952.

    That was fun ... and maybe even right! tongue 

    The reason I say that is, the same alternate date code was used by some companies into the 1970's ... don't know about TungSol specifically ...

    Then again, I see some hints that they only did the black glass in the 1950's ...

    And, if you can find one with "JTL" preceeding the code, that's the military version and commands a premium price.

    Either way, one fine tube there ... consensus is smooooooooth ... only complaint is they tend to be a bit microphonic, so you may want to think about damping it if that's a problem.

    Thanks for your info.  
    may be 50s  
    will try some JTL military version too. around 60 to 70
    thanks again

    sKiZo

    Posts : 1308
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by sKiZo on Thu Aug 22, 2013 2:48 pm

    PS ... thanx for the tube reviews. I've got a couple Brimar's that I want to try as side drivers on the ST120 when I get it up and running ... I was also planning to start out with three RCA clear tops as they're inexpensive and get good reviews.

    I have high hopes for these too ...



    The Tele is a diamond bottom that tests new (not sure on the date) and the Gulbransen's are matched, rebadged Amperex Bugle Boys.

    simonfck

    Posts : 15
    Join date : 2013-03-04

    Re: Tung Sol Black Glass 12AU7 square getter

    Post by simonfck on Fri Aug 23, 2013 4:29 am

    Amperex "triangle" or "delta" date codes  Holland Heerlen,
    2K2 maybe 1962

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