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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


4 posters

    second choke

    golnie
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    golnie


    Posts : 3
    Join date : 2015-12-31
    • Post n°1

    second choke Empty second choke

    Post by golnie Thu Feb 18, 2016 5:56 pm

    I recently put a VTA board in my ST-70 and I love it.  With the VTA board, my ST-70 sounds as good if not better than my Marantz 8B (I hope I didn't start a jihad with that statement) . I would like to put a second choke in the ST-70. Would it be wired in series or parallel to the first choke? BTW the ST-70 has the larger power transformer. Thank you in advance for any help.

    Frank
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    j beede
    j beede
    j beede


    Posts : 473
    Join date : 2011-02-07
    Location : California
    • Post n°2

    second choke Empty Re: second choke

    Post by j beede Thu Feb 18, 2016 6:53 pm

    It depends... if you want to shorten the life of your rectifier put the second choke in parallel with the first. If you want to lower your B+ and alter cathode bias put the second choke in series.

    What are you trying to accomplish?
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    golnie
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    golnie


    Posts : 3
    Join date : 2015-12-31
    • Post n°3

    second choke Empty second choke

    Post by golnie Thu Feb 18, 2016 7:40 pm

    Hi, I noticed that the ST-120 uses a second choke. I would like to use a second choke for more filtering. I have SS rectifying with 3 amp diodes.

    Thank you for your reply.

    Frank
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    nmchiefsfan
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    nmchiefsfan


    Posts : 78
    Join date : 2012-03-21
    • Post n°4

    second choke Empty Re: second choke

    Post by nmchiefsfan Mon Feb 22, 2016 5:52 pm

    Golnie, I am pretty sure the 2nd choke is wired in parallel with the 1st one.
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    Guest
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    Guest
    Guest


    • Post n°5

    second choke Empty Re: second choke

    Post by Guest Mon Feb 22, 2016 7:07 pm

    nmchiefsfan wrote:Golnie, I am pretty sure the 2nd choke is wired in parallel with the 1st one.

    yes it is indeed!
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    Bob Latino
    Bob Latino
    Bob Latino
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    Posts : 3276
    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°6

    second choke Empty Re: second choke

    Post by Bob Latino Mon Feb 22, 2016 7:12 pm

    The VTA ST-70 only needs one choke. The ST-120 and M-125's use two chokes. The primary reason why the two chokes are in there is to handle more current. A single C24-X choke will handle 240 milliamps which is fine for the ST-70. The ST-120 and the M-125's draw more current so the second C24-X choke is used.

    Bob
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    golnie
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    golnie


    Posts : 3
    Join date : 2015-12-31
    • Post n°7

    second choke Empty Re: second choke

    Post by golnie Tue Feb 23, 2016 9:31 am

    Thank you for your replies. I will leave well enough alone and just use one choke.

    Frank
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    • Post n°8

    second choke Empty Re: second choke

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