The Dynaco Tube Audio Forum

Would you like to react to this message? Create an account in a few clicks or log in to continue.
The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Tubes4hifi VTA tube amp and preamp kits and all Dynakitparts.com products


3 posters

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

    avatar
    olds442111


    Posts : 8
    Join date : 2014-01-18

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

    Post by olds442111 Sat Jan 25, 2014 12:09 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
    sKiZo


    Posts : 1530
    Join date : 2013-04-01
    Location : Michigan USA

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

    Post by sKiZo Sat Jan 25, 2014 2:16 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 
    avatar
    olds442111


    Posts : 8
    Join date : 2014-01-18

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

    Post by olds442111 Fri Feb 14, 2014 3:16 am

    or not, haha
    Bob Latino
    Bob Latino
    Admin


    Posts : 3260
    Join date : 2008-11-26
    Location : Massachusetts

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

    Post by Bob Latino Fri Feb 14, 2014 4:58 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
    avatar
    olds442111


    Posts : 8
    Join date : 2014-01-18

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

    Post by olds442111 Fri Feb 14, 2014 7:18 pm

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

    Sponsored content


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

    Post by Sponsored content


      Current date/time is Thu Mar 28, 2024 2:29 pm