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    Question about A470 transformers screen voltage pins



    Posts: 2
    Join date: 2009-12-25

    Question about A470 transformers screen voltage pins

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


    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



    Posts: 58
    Join date: 2009-01-19

    Dynaco Transformers

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


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


    Bob Latino

    Posts: 2263
    Join date: 2008-11-26
    Location: Massachusetts

    Re: Question about A470 transformers screen voltage pins

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


    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



    Posts: 2
    Join date: 2009-12-25

    Output transformer

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

    Thanks for the ideas :-)

    It is very useful for me :-)


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