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    Which hammond power transformer for a ST70 clone

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    starwatcher

    Posts : 11
    Join date : 2018-02-26

    Which hammond power transformer for a ST70 clone

    Post by starwatcher on Wed Aug 22, 2018 6:53 pm

    Hello.

    I am currently plan to build a ST70 clone for a friend.

    I already have a pair of hammond 1650k i got for cheap who are used in a project on DIYaudio.

    http://www.diyaudio.com/forums/tubes-valves/298927-dynaco-st-70-original-mod-6.html

    But he seems to use a separate filament transformer with a 363CX.

    Solid state or tube rectifier don't really matter.

    Regards.
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    peterh

    Posts : 1054
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Which hammond power transformer for a ST70 clone

    Post by peterh on Thu Aug 23, 2018 2:02 am

    starwatcher wrote:Hello.

    I am currently plan to build a ST70 clone for a friend.

    I already have a pair of hammond 1650k i got for cheap who are used in a project on DIYaudio.

    http://www.diyaudio.com/forums/tubes-valves/298927-dynaco-st-70-original-mod-6.html

    But he seems to use a separate filament transformer with a 363CX.

    Solid state or tube rectifier don't really matter.

    Regards.
    I think the title is wrong. The amp describes is no st70, it's another EL34 based amp and has
    no place in "dynacotubeaudio" .
    avatar
    ViperZ

    Posts : 63
    Join date : 2010-03-26

    Re: Which hammond power transformer for a ST70 clone

    Post by ViperZ on Thu Aug 23, 2018 9:38 am

    The question can easily be rephrased to - which Hammond power transformer could be used to replace the original PA-060 transformer...
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    Peter W.

    Posts : 966
    Join date : 2016-08-07
    Location : Melrose Park, PA

    Re: Which hammond power transformer for a ST70 clone

    Post by Peter W. on Thu Aug 23, 2018 1:29 pm

    https://www.hammfg.com/electronics/transformers/classic/300

    Is a link to Hammond transformers that include the one you linked.

    This is the spec for the PA 060: Secondary B+ winding is 720VCT (360-0-360) at 300 ma with 55V bias tap, plus two 6.3VCT 5 amps & one 5V 4 amp tube filament & rectifier windings.

    As you can see:

    a) The transformer you specified has a very low B+.
    b) The reason for the outboard filament transformer is that the CX lacks any 6.3V winging(s).

    That is no Dynaco Clone.

    zx

    Posts : 205
    Join date : 2011-08-05

    Re: Which hammond power transformer for a ST70 clone

    Post by zx on Thu Aug 23, 2018 1:56 pm

    Here are great ST70 replaments parts….http://triodeelectronics.com/st70boards.html

    http://triodeelectronics.com/mq060.html

    good luck have fun...



    thanks for the site Bob...…….

    starwatcher

    Posts : 11
    Join date : 2018-02-26

    Re: Which hammond power transformer for a ST70 clone

    Post by starwatcher on Thu Aug 23, 2018 7:28 pm

    Thanks for your answers.
    I finally order a suitable Tomiko toroidal transformer for 140$
    The amp is for a friend so final price is a issue. I check before for Edcor transformers ans final cost in CAD is 2X the price in USD.
    The original circuit board will come from China and i will use the tubes i have in hand.
    I plan to use 6gh8 and 6L6 or 6BG6.
    Final cost will be under 400$ CAD.
    Regards.
    avatar
    ViperZ

    Posts : 63
    Join date : 2010-03-26

    Re: Which hammond power transformer for a ST70 clone

    Post by ViperZ on Mon Aug 27, 2018 11:04 am

    Can you show a link to the transformer that you ordered? Thanks.

    This one?
    http://dynacotubeaudio.forumotion.com/t937-power-transformer-options-st-70

    starwatcher

    Posts : 11
    Join date : 2018-02-26

    Re: Which hammond power transformer for a ST70 clone

    Post by starwatcher on Tue Aug 28, 2018 12:59 am

    Yes it's this one.
    There's no link for now, i know the guy i buy parts from him in the past.

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