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    Complete ST-70 restoration



    Posts : 221
    Join date : 2009-02-05
    Location : Central New Jersey

    Complete ST-70 restoration

    Post by Sal on Tue Sep 17, 2013 10:28 pm

    I just completed a complete Dynaco ST-70 restoration including a new chassis and printed circuit board from Kevin at The ST-70 was a mess and I was just going to replace the chassis, paint the transformers and replace all the capacitors etc. The wiring was a complete mess so I decided to rebuild the whole amplifier since I didn't want my name associated with the bad wiring....

    I reused the tube socket, transformers, choke, and a few other parts. Every resistor has been replaced since there is a new PC-3 board and I replaced every resistor under the chassis. The Bias controls were replaced earlier by someone who redid the poor wiring job.

    Here are a few before and after pictures... Just right click each picture and click view image to see the whole picture...



    Posts : 88
    Join date : 2011-09-20

    Re: Complete ST-70 restoration

    Post by kaner on Tue Sep 17, 2013 11:20 pm

    Excellent work! The transformers look brand new. Was that some sort of chrome finish on the unrestored bells? By the way, I like your bench engraving. Is that from your kids? Mine aren't as kind. My kids made a sign for over my bench that say "Nerdatorium". Anyway, your rebuild is something to be proud of.


    Posts : 221
    Join date : 2009-02-05
    Location : Central New Jersey

    Re: Complete ST-70 restoration

    Post by Sal on Tue Sep 17, 2013 11:35 pm

    Thank you for your compliment, the chassis and endbells were brass plated before I restored the amp. The endbells were powder coated and the cores were sanded, 2 coats of primer and 2 coats of black semi-gloss Rustomleum spray paint.

    My daughter occasionally uses my Sharpie marker to write on my bench. Here is another messgae she left me... By the way, my daughter is 22 years old... What can I say.... I'm a cool dad... Embarassed




    Posts : 1336
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Complete ST-70 restoration

    Post by sKiZo on Wed Sep 18, 2013 1:02 pm

    I'm thinking you wouldn't be quite so understanding if she did a few doodles on that shiny "new" amp ...

    Nice job, and incentive for dumpster divers everywhere!

    PS ... you shot peen the inside or splatter paint?


    Posts : 406
    Join date : 2008-12-05

    Re: Complete ST-70 restoration

    Post by PeterCapo on Wed Sep 18, 2013 2:35 pm

    Nice work, Sal


    Posts : 181
    Join date : 2008-11-30

    ST-70 Restoration

    Post by DynakitParts on Wed Sep 18, 2013 9:14 pm

    As always..nice workmanship.



    Posts : 58
    Join date : 2012-09-16
    Age : 43
    Location : amsterdam

    Re: Complete ST-70 restoration

    Post by nerpissad on Thu Sep 19, 2013 9:48 am

    really impressed with the way you re-wired everything. my ST70 looks more like yours in its original state as far as wiring is concerned. someday I will rewire it and aim for something like you have done Wink


    Posts : 221
    Join date : 2009-02-05
    Location : Central New Jersey

    Re: Complete ST-70 restoration

    Post by Sal on Thu Sep 19, 2013 10:29 am

    Thank you all for the compliments.



    Posts : 362
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Complete ST-70 restoration

    Post by arledgsc on Fri Sep 20, 2013 10:34 am

    Wow!   What a dramatic change for the better.  Excellent job on restoration!


    Posts : 233
    Join date : 2009-02-04
    Age : 66
    Location : Texas

    Re: Complete ST-70 restoration

    Post by Luddite on Tue Sep 24, 2013 10:58 am

    Sal always does first class work!

    Best Regards,


    Posts : 81
    Join date : 2012-05-05

    Re: Complete ST-70 restoration

    Post by DarthBubba on Tue Sep 24, 2013 5:45 pm

    Very much a "Beauty and the Beast" transformation! cheers 

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