The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    A470 Outputs [wiring question]

    Share

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    A470 Outputs [wiring question]

    Post by Clik2media on Wed Oct 20, 2010 3:45 pm

    Can output trannies be partially new? or newer?
    I am looking at my ST70 guts and noticed some leads are cloth covered and some are plastic? Leads to speaker outputs are plastic [yellow,orange,brown, black] and red leads to cap is plastic, the other leads to tubes are cloth.
    The bells are in excellent condition tempting me to conclude "new or newer" outputs

    DynakitParts
    Admin

    Posts : 181
    Join date : 2008-11-30

    Dynaco A-470 transformers

    Post by DynakitParts on Wed Oct 20, 2010 4:30 pm


    Hi,
    PVC leads indicate a newer production version. I have seen this mix of
    of cloth & PVC leads on other Dynaco transformers. At one point PVC
    totally replaced cloth covered leads in consumer products. Perhaps the
    transformer provider at the time "Tresco" from Philadelphia was in the
    process of changing over to PVC and had a remaining inventory of the
    cloth lead stock which they used on the transfomers.
    Dynaco's last supply of transformers came from Japan...I have several
    samples of these which I removed the end bells for close inspection.

    IMHO these were poorly made and typical of what one would expect from
    the Chinese today. If I get a chance...I will post a few photos.

    Another indicator of a newer production transformer is the labeling of
    the covers. Early versions were metal stamped "Embossed" whereas the
    later production labeling was an a white ink stamping.

    Regards,

    Kevin

    Clik2media

    Posts : 40
    Join date : 2009-01-18

    A470

    Post by Clik2media on Wed Oct 20, 2010 5:30 pm

    Thnx very much for that clarification.

    "IMHO these were poorly made and typical of what one would expect from the Chinese today. If I get a chance...I will post a few photos."

    Curious just how bad are they? LOL I am rebuilding it and wondering if I should go all the way with it $wise?

    Mine are "stamped" btw.

    thnx

    DynakitParts
    Admin

    Posts : 181
    Join date : 2008-11-30

    Dynaco A-470...Made in Japan

    Post by DynakitParts on Wed Oct 20, 2010 11:19 pm

    Hi,
    Purchased a small mixed lot of Dynaco NOS transformers a while back
    sight unseen...Older gent from Chicago area who did not have internet
    capability or a camera. Trusted his description & sent him off the $$.

    A mixed group of MK III transformers, a few PA-135's, C-354 cokes and
    (4) A-470's. All the power transformers were dual voltage 120/240 which
    was a rare find. All were unused but in need of re-painting since they
    were not propery packaged by the seller.

    The (4) A-470's had the PVC leads...no cloth lead mix like yours.
    Attempted to remove the covers from one of these units for painting
    but they would not budge after removing the hardware. Finally pried
    off one cover which pulled the output leads completely out of the
    windings. The inside of the covers was totally encapsulated with a
    hardened shelac like resin. The remaining A-470's were the same.

    Since this transformer was already damaged..I cut open the windings
    at the face of the laminations which revealed the various layering of
    each of the windings. At the core you could see pieces of wood used as
    a filler to form the core at the center of the winding. The voids were
    also filled with this resin like material. Workmanship was surprisingly
    bad...

    These were not made here in the USA..And I strongly suspect these were
    made in Japan.

    I hope you do not have a pair these transformers..Try removing the covers
    carefully...If the come off easily then you are home free. If not...
    I would buy a small boat in need of an anchor. LOL.

    Regards,

    Kevin








    Clik2media

    Posts : 40
    Join date : 2009-01-18

    A470 - bells off

    Post by Clik2media on Thu Oct 21, 2010 12:07 am

    Hi Kevin, I decided I couldn't wait till tomoro to find out ...LOL
    Turns out mine are fine - bells dropped off after screws were pulled. Inside was light wax/shellac? and paper protecting the windings. Needless to say I was relieved as I would rather buy more Dynaco's than a small boat... Very Happy

    Sponsored content

    Re: A470 Outputs [wiring question]

    Post by Sponsored content Today at 1:04 am


      Current date/time is Wed Sep 28, 2016 1:04 am