The Dynaco Tube Audio Forum

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


    Value of B+ on 12at7 Mark3 board?

    Share

    garyb

    Posts : 3
    Join date : 2011-01-06
    Location : Iowa

    Value of B+ on 12at7 Mark3 board?

    Post by garyb on Tue Jan 18, 2011 12:24 pm

    Hi, what should the value of B+ on VTA 12at7 Mark3 board be?
    Thanks
    Gary

    quad44

    Posts : 15
    Join date : 2009-06-08

    Re: Value of B+ on 12at7 Mark3 board?

    Post by quad44 on Tue Jan 18, 2011 1:35 pm

    The documented value for B+ for the VTA MK3 board is +400VDC. This is the value of the voltage from the power supply.
    The plate voltage for the first 12AT7 is 150VDC and 300VDC for the phase inverter(second 12AT7).
    Hope this helps.

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Value of B+ on 12at7 Mark3 board?

    Post by Bob Latino on Tue Jan 18, 2011 3:26 pm

    On the Mark III with a VTA driver board anything between about 400 VDC to maybe 430 VDC is normal for the B+ line coming into the driver board at the driver board's "B+" eyelet. Solid state rectifiers and/or a higher incoming AC line voltage will give a B+ near the upper end of this range.

    Bob

    garyb

    Posts : 3
    Join date : 2011-01-06
    Location : Iowa

    Thanks for your responses

    Post by garyb on Wed Jan 19, 2011 3:09 am

    Hi, just wanted to say thanks for your help. The Mark 3 twins have been up and running for a couple of hours and I really like the result. I've had a ST 70 with the VTA high gain board for several months and I was so impressed the twins got the same treatment.
    Many thanks
    Gary

    Sponsored content

    Re: Value of B+ on 12at7 Mark3 board?

    Post by Sponsored content Today at 2:55 am


      Current date/time is Sat Oct 01, 2016 2:55 am