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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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    st-35 triode output

    altecboy
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    altecboy


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    Join date : 2013-09-23
    • Post n°1

    st-35 triode output Empty st-35 triode output

    Post by altecboy Mon Sep 23, 2013 4:44 am

    I built a clone st35 using Dynakitparts boards. I'd like to run it in triode. In the St35 the ultralinear connection has a feedback connection. Other than removing the UL connection at the output tube screens, and using a 100 ohm resistor between the screens and the plates, what more need be done?

    thanks.
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    Bob Latino
    Bob Latino
    Bob Latino
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    • Post n°2

    st-35 triode output Empty Re: st-35 triode output

    Post by Bob Latino Mon Sep 23, 2013 8:51 am

    altecboy wrote:I built a clone st35 using Dynakitparts boards.  I'd like to run it in triode.  In the St35 the ultralinear connection has a feedback connection.  Other than removing the UL connection at the output tube screens, and using a 100 ohm resistor between the screens and the plates, what more need be done?

    thanks.
    What you mentioned above is all that needs to be done .. Just remember to insulate the end of the ultralinear wire. That wire is carrying about 380 volts ..

    Power will be reduced to about 9 or 10 watts per channel on the ST-35 if you run it in triode ...

    Bob
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    altecboy
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    altecboy


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    • Post n°3

    st-35 triode output Empty Re: st-35 triode output

    Post by altecboy Mon Sep 23, 2013 9:57 am

    Thank you Bob. There is this feed back capacitor associated with the screens. I think it should be removed as well. Do you agree?
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    Bob Latino
    Bob Latino
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    • Post n°4

    st-35 triode output Empty Re: st-35 triode output

    Post by Bob Latino Mon Sep 23, 2013 12:05 pm

    You could probably try it both ways ... Leaving it in and removing it and see if it has any affect on the sound ..

    I think that 18 pF (C6) cap is in there to assure that the circuit is stable - BUT - I have a feeling that if it is removed, the circuit will still be stable ..

    Bob
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    altecboy
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    altecboy


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    • Post n°5

    st-35 triode output Empty Re: st-35 triode output

    Post by altecboy Mon Sep 23, 2013 12:30 pm

    Thank you Bob.
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