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 products and all products

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    Join date : 2012-01-01

    New to this forum

    Post by grizzinca on Thu Jan 05, 2012 10:14 am

    I'm really learning alot from this forum, but I am new to tube audio. I recently purchased a st 70 off ebay, and not quite sure what I have. When I powered it up, one tube never heated up, but due to my lack of knowledge and lack of patience I ran it anyway. Oh!! The sound was all I heard it was. New tubes on the way. My question is ...what is the cardboard tube opposite the cap cannister? It has writing...30 to 40 MFD, BB0530A, UPN 10779 and the letters AJ. The pics I've seen of st70's show a tube where this part sits. Thanks for the help. Hope to learn much more


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    Re: New to this forum

    Post by GP49 on Thu Jan 05, 2012 1:13 pm

    Sounds like someone has replaced the tube rectifier with a silicon diode rectifier, and added a supplemental power supply capacitor.

    Probably it would be best to take this thread to the regular board, where tech issues are discussed. Bob may be able to do it since he
    runs the forum.

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