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    ST-70 rebuild

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    willieher

    Posts: 6
    Join date: 2009-04-19
    Age: 61
    Location: Ohio

    ST-70 rebuild

    Post by willieher on Wed Apr 22, 2009 4:20 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.

    http://i943.photobucket.com/albums/ad271/willieher/amplifier006.jpg

    http://i943.photobucket.com/albums/ad271/willieher/amplifier005.jpg

    http://i943.photobucket.com/albums/ad271/willieher/amplifier003.jpg

    http://i943.photobucket.com/albums/ad271/willieher/amplifier001-1.jpg


    Last edited by willieher on Sun Jul 12, 2009 4:21 pm; edited 6 times in total

    Bob Latino
    Admin

    Posts: 1908
    Join date: 2008-11-26
    Location: Massachusetts

    Re: ST-70 rebuild

    Post by Bob Latino on Sat Apr 25, 2009 4:14 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

    willieher

    Posts: 6
    Join date: 2009-04-19
    Age: 61
    Location: Ohio

    Re: ST-70 rebuild

    Post by willieher on Tue Apr 28, 2009 9:46 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.

      Current date/time is Mon Sep 01, 2014 1:31 pm