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    Low gain VTA70 driver board...has a 12at7 been tried?

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    olds442111

    Posts : 8
    Join date : 2014-01-18

    Low gain VTA70 driver board...has a 12at7 been tried?

    Post by olds442111 on Sat Jan 25, 2014 5:09 am

    Has anyone tried, or is it frowned upon, to try a 12at7 in the low gain driver board? Only reason I ask is that I have tons of these tubes, and didn't know if this were possible with this board or not. Any feedback is appreciated.

    sKiZo

    Posts : 1285
    Join date : 2013-04-02
    Location : Michigan USA

    Re: Low gain VTA70 driver board...has a 12at7 been tried?

    Post by sKiZo on Sat Jan 25, 2014 7:16 am

    Not recommended, and I'm sure Bob will be along shortly to give you a severe frowning ...

    This will have to hold you for now ...  Evil or Very Mad 

    PS ... I've got some nice Amperex Holland 12AT7's here that I picked up before I got the word on the high vs low boards. Make me an offer.  tongue 

    olds442111

    Posts : 8
    Join date : 2014-01-18

    Re: Low gain VTA70 driver board...has a 12at7 been tried?

    Post by olds442111 on Fri Feb 14, 2014 8:16 am

    or not, haha

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-27
    Location : Massachusetts

    Re: Low gain VTA70 driver board...has a 12at7 been tried?

    Post by Bob Latino on Fri Feb 14, 2014 9:58 am

    The resistor set has been altered from the older higher gain board as opposed to the newer lower gain board to optimize the board for the lower gain 12AU7 type driver tubes. (8 resistors on each channel are different from one board to the other) The newer board also has "CCS" (a constant current source in the tail of the phase splitter). I don't recommend the use of 12AT7 driver tubes in the newer lower gain CCS board. It may work but gain will be higher and the 12AT7 tubes that you use will not be operating optimally.

    Bob

    olds442111

    Posts : 8
    Join date : 2014-01-18

    Re: Low gain VTA70 driver board...has a 12at7 been tried?

    Post by olds442111 on Sat Feb 15, 2014 12:18 am

    Thanks Mr. Bob. Just wanted some input on it.

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