Van Alstine MOSFET Amp Info Wanted

Discussion in 'Audio by Van Alstine' started by kve777, Apr 23, 2016.

  1. kve777

    kve777 AK Subscriber Subscriber

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    South Jersey, near Philly
    I picked up this "Dynaco Mystery Amp" from a fellow AK'er recently and found the boards are VanAlsine PC-489, and the outputs are Hitachi 2SK134 and 2SJ49 MOSFET's, but can't seem to find out anything more about it, like a model # or specs. Apparently it's about 55 WPC or so, based on the output devices. I just wish I had a model # or something to verify. It's in a Dynaco ST-150 cabinet, I believe. Any info would be appreciated.

    IMG_1374.JPG IMG_1375.JPG IMG_1376.JPG
     

     

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  2. Pio1980

    Pio1980 AK Member Subscriber

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    Maybe move this to the AVA forum.
     
  3. luvvinvinyl

    luvvinvinyl Aggie! Staff Member Admin Subscriber

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    I can vouch for that.

    I can move this thread for you, if you wish.
     
  4. kve777

    kve777 AK Subscriber Subscriber

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    Bump for info.
     
  5. avahifi

    avahifi AK Member

    Messages:
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    Location:
    Woodbury, Minnesota
    Well! That is certainly an interesting but unauthorized use of AVA circuits. We never built anything like that in a Dyna ST-150 chassis.

    It appears that the AVA circuit boards, and Dyna SCA-80 heat sinks with our Hitachi mosfets installed have been removed from an older Dyna chassis and cobbled into this Dyna St-150 chassis. The toroid power transformer is not ours either and I have no idea of its current or voltage rating.

    I also note that the audio circuits are missing output inductors and critical output circuit damping networds, so its stability is suspect. Here is a more representitive photo of what a real AVA circuit set in a Dyna ST-150 should look like.

    Frank Van Alstine

    Mos-Fet-150.png upload_2016-4-26_9-26-32.png
     

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