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The Dynaco Tube Audio Forum

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


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    Question about A470 transformers screen voltage pins

    kovacslori
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    kovacslori


    Posts : 2
    Join date : 2009-12-25
    • Post n°1

    Question about A470 transformers screen voltage pins Empty Question about A470 transformers screen voltage pins

    Post by kovacslori Sat Jan 02, 2010 4:01 pm

    Hi,

    Could anyone help for me Please!
    I intended to build st70 amplifier, but I'm living in Hungary in the midle of Europe and it is not so easy...and not so cheap to get the output transformers for the amp. I'd like to make it by myself with my friend. The question is...

    The output transformer primer side has 5 pins. The impedance alltogether is 4300Ohm. This understood:-) I understood that the high voltage should be connected to the middle point of the seconder. How should I place the pins of the transformator for the screens of EL34 tubes. What is the rate of windings for the screen voltage pins?
    How can I figure it out?

    Thanks in advance

    lori
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    danf
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    danf


    Posts : 58
    Join date : 2009-01-19
    • Post n°2

    Question about A470 transformers screen voltage pins Empty Dynaco Transformers

    Post by danf Sun Jan 03, 2010 9:05 am

    Hi,

    I think that a do-it-yourself transformer is going to be hard, but have a look at:

    http://www.one-electron.com/trans_p1.pdf

    Regards,
    Dan
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    Bob Latino
    Bob Latino
    Bob Latino
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    Posts : 3272
    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°3

    Question about A470 transformers screen voltage pins Empty Re: Question about A470 transformers screen voltage pins

    Post by Bob Latino Sun Jan 03, 2010 12:01 pm

    Kovacslori,

    A few people have taken A-470 output transformers apart and counted the number of turns per winding and noted the wire sizes. One of the best winding diagrams for the Dynaco A-470 output transformer I have seen is a thread on the Diytube forum at the link below. You could use the diagram at this link to try and wind your own output transformer ...

    Dynaco A-470 winding diagrams for the A-470 output transformer

    Bob
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    kovacslori
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    kovacslori


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    Join date : 2009-12-25
    • Post n°4

    Question about A470 transformers screen voltage pins Empty Output transformer

    Post by kovacslori Sun Jan 03, 2010 2:02 pm

    Thanks for the ideas :-)

    It is very useful for me :-)


    lori
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    Question about A470 transformers screen voltage pins Empty Re: Question about A470 transformers screen voltage pins

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