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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


    Dynaco Mk III to VTA HELP.......

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    tubed1

    Posts : 17
    Join date : 2012-01-03

    Dynaco Mk III to VTA HELP.......

    Post by tubed1 on Wed Oct 07, 2015 2:00 pm

    I realize I can purchase raw or stuffed MkIII boards for my Mk III upgrades via Roy.  Why not a kit?  Having only built one tube amplifier in my lifetime I would welcome the step by step instructions on how to install & test the VTA MK III boards.  Actually trying to modify an old mono block of GSI MK III into VTA MK III.  The chasis are black chrome and look awesome!!!!   Can I keep the power supply from GSI?    

    Am I just missing something?  Apparently so, the instruction set>?

    stewdan

    Posts : 160
    Join date : 2010-03-07
    Age : 78
    Location : Houston Texas

    Re: Dynaco Mk III to VTA HELP.......

    Post by stewdan on Wed Oct 07, 2015 2:30 pm

    Hi -- Unless I am misreading your Post, Roy has VTA Mk3 Boards in the following flavors --- (1) PCBs only, (2) Stuffed Boards and (3) PCBs plus the parts or what you are calling a kit.  

    The only Mk3 Amplifier Full Kits that are out there are what is listed on the Dynakitparts.com and the Triodeelectronics.com websites, but those are clone kits of the original Dynaco Design, but with better Power Transformers.

    I have bought several of Roy's VTA Mk3 kits, in Noval 12AU7 form or Octal 6SN7 form.

    As to how they would interface with the GSI Power Stage, that I don't remember off the top of my head.  I have hooked Roy's VTA boards up to the Triode Quad Cap Replacement Board, but not the GSI.

    If I remember correctly, back in the early 1990's GSI offered some dynaco upgrade boards which  were reported on by Roy (I think) in the Glass Audio Magazine.

    Try doing a google search on GSI Dynaco Upgrades and see if you can locate some documentation???

    Any questions, ask away.

    Hope this helps,
    Stew

    stewdan

    Posts : 160
    Join date : 2010-03-07
    Age : 78
    Location : Houston Texas

    Re: Dynaco Mk III to VTA HELP.......

    Post by stewdan on Wed Oct 07, 2015 2:47 pm

    Hi Again --- I did google scan for dynaco and GSI and got lots of references for the ST70 GSI Board, but nothing for the Mk3 GSI board. There was even a pointer to Roy's Glass Audio article where is talks about the GSI board, but for the ST70.

    I remembered that GSI had a ST70 Upgrade board, but was not aware of the Mk3 Board specifics.

    I also did not find any documentation listed.

    You might have to take some pictures of the underside of you amp to see how it is wired and post the pictures of the forum to get feedback from our readers on how to rewire for the VTA board.......Assuming that GSI Power Transformer is wired the same as the standard Dynaco Transformer.

    Stew

    tubed1

    Posts : 17
    Join date : 2012-01-03

    Re: Dynaco Mk III to VTA HELP.......

    Post by tubed1 on Wed Oct 07, 2015 3:45 pm

    Thanks again for all of your timely assistance and direction Stew.  This will be a challenge well worth the undertaking.

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: Dynaco Mk III to VTA HELP.......

    Post by tubes4hifi on Thu Oct 08, 2015 12:01 pm

    Tubed1 (obi-one) . . .  did you notice I DO sell MK3 full amplifier kits, with the VTA mod?  
    Buy button just below the boards and the tubes. Lots of photos at the bottom of my MK3 page
    I sell several pairs of these every year!    www.tubes4hifi.com/MK3.htm

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