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    Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

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    Bob Latino
    Admin

    Posts : 2411
    Join date : 2008-11-26
    Location : Massachusetts

    Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

    Post by Bob Latino on Tue Sep 17, 2013 1:12 pm



    At one time in the 1990's a Chinese manufacturer (Shenzhen Valve Audio Lab) attempted to sell a "clone" of the Dynaco ST-70 amp in KIT form. Evidently it was poorly designed with a really bad driver circuit using a single ECF82 tube on each channel (never even heard of this tube before ?) and cheap output transformers with very high distortion in the treble area. See the link below about how a user did some upgrades on the amp ...

    Fixing the Chinese VAA-70 MK II

    Another link below on the Diyaudio Forum about this amp ...

    Chinese VAA-70 MK II on the Diyaudio forum

    Bob

    anbitet66

    Posts : 132
    Join date : 2009-12-23
    Location : Valley Stream, NY

    Re: Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

    Post by anbitet66 on Tue Sep 17, 2013 3:31 pm

    Thank you Bob!  I knew about these amps back about '96 or '97 from both Parts Express and MCM Electronics.  They sold for about $300 to $350  or for about $50 less they were available in kit form, and a matching preamp was available.  I saw the input tube was a 6F2 (no clue what that was) so I held off until about 1999 to purchase one only to find out it had just been discontinued.  

    I've always felt that I missed out on something, and that was why I eventually sourced the parts to build an ST70 clone.  Now I don't feel so bad that I didn't pull the trigger sooner.  Still, for the money, it might have been fun to try to make a silk purse out of a sows ear silent .

    peterh

    Posts : 679
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

    Post by peterh on Wed Sep 18, 2013 2:02 am

    ecf82 is a common tube in europe, it is somewhat similar to 7199 . Not unusual at all !

    sKiZo

    Posts : 1308
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

    Post by sKiZo on Wed Sep 18, 2013 12:56 pm

    ... and if I'm reading it correctly, the final verdict, after all the work and upgrades, was ... eh.

    Still, looks like a fun experiment if you ever find one laying about. Lot of good groundwork laid, and just need to find that certain something to make it sing ...

    eh
    ooPs
    eh
    argh
    eh
    AAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHH!!

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    Re: Chinese Dynaco ST-70 type amp KIT of the 1990's - the VAA-70 MKII

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