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


2 posters

    ST-70 rebuild

    avatar
    willieher


    Posts : 8
    Join date : 2009-04-19
    Age : 71
    Location : Ohio

    ST-70 rebuild Empty ST-70 rebuild

    Post by willieher Wed Apr 22, 2009 5:20 pm

    My name is Willie and I finnaly finished rebuilding my ST-70
    I've been working on it off and on for a few months.
    As you can see I have made a few changes from the original
    design. I replaced the 4 small caps on the driver board with
    2 larger MUNDORF M-LYTIC 100-100 uf.caps,under the board I
    replaced the onboard rectifier with a FAIRCHILD TO-220
    high speed soft recovery rectifier I also replaced the
    2,onboard 100uf.-100v caps with 2, BLACK GATE 100uf.-100v.
    I had to move a few parts under the amp. The the quad cap and
    the new WEBER solid state rectifier are now laying down.
    I had to move the power swich and the fuse to get these to
    fit. You can also see that I placed 2,ALPS BLACK-BEAUTY pots
    where the 2,bias controls were this is the only place I
    could fit them ,from the top you can see that I have to
    reach to turn the volume knobs. Most of the board wiring
    is done using KIMBER 19ga. solid core silver wire,the front
    inputs are also KIMBER,I had to file some of the edges off to
    get these to fit. Things under the hood got a little cramped
    but I think I did a good job at wire management and as neet as
    I could get it. I would say that this was quite an undertaking
    for myself and quite a suprise when I turned it on and all the
    tubes lit up. I almost forgot to mention the AMP sounds great.
    This AMP is using the high gain driver board with a compliment
    of 3 JAN PHILIPS 12AT7WC high gain tubes. My ALPS POTS will be
    used as a passive PRE-AMP.

    https://2img.net/h/i943.photobucket.com/albums/ad271/willieher/amplifier006.jpg

    https://2img.net/h/i943.photobucket.com/albums/ad271/willieher/amplifier005.jpg

    https://2img.net/h/i943.photobucket.com/albums/ad271/willieher/amplifier003.jpg

    https://2img.net/h/i943.photobucket.com/albums/ad271/willieher/amplifier001-1.jpg


    Last edited by willieher on Sun Jul 12, 2009 5:21 pm; edited 6 times in total
    Bob Latino
    Bob Latino
    Admin


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

    ST-70 rebuild Empty Re: ST-70 rebuild

    Post by Bob Latino Sat Apr 25, 2009 5:14 pm

    Willie,

    I have never seen an ST-70 with a VTA driver board built the way you did ? You did a helluva nice job. I especially like your heavy duty "star" grounding system next to the choke.

    Bob
    avatar
    willieher


    Posts : 8
    Join date : 2009-04-19
    Age : 71
    Location : Ohio

    ST-70 rebuild Empty Re: ST-70 rebuild

    Post by willieher Tue Apr 28, 2009 10:46 am

    Hi Bob,I want to thank you for the compliment, it means a lot comming from you. Since I posted my ST-70 I have replaced the
    4 EL-34s with a mached quad of TUNG-SOL EL-34B.
    The AMP sounds even better. Thanks for your help with this rebuild.

    Sponsored content


    ST-70 rebuild Empty Re: ST-70 rebuild

    Post by Sponsored content


      Current date/time is Thu Mar 28, 2024 3:51 pm