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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


3 posters

    ST-35 power switch.

    daveshel
    daveshel
    daveshel


    Posts : 169
    Join date : 2011-11-06
    Location : Tucson AZ USA
    • Post n°1

    ST-35 power switch. Empty ST-35 power switch.

    Post by daveshel Thu Mar 31, 2016 9:19 pm

    Still loving my ST-35. When I got it, the previous owner had rigged a power switch in a 1/2" hole on the front panel. The contacts were very close to the edges of the switch, and he had insulated it from the top of the chassis with some duct tape. I thought that was dangerous and ripped it out.

    I'd like to add a power switch using the existing hole. Can anyone recommend a switch that will fit in this small chassis (I have to use the front because the EFB board uses up all the top real estate), clear the top and bottom, and fit in a 1/2" hole?
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    peterh
    peterh
    peterh


    Posts : 1833
    Join date : 2012-12-25
    Location : gothenburg, sweden
    • Post n°2

    ST-35 power switch. Empty Re: ST-35 power switch.

    Post by peterh Fri Apr 01, 2016 2:04 am

    daveshel wrote:Still loving my ST-35. When I got it, the previous owner had rigged a power switch in a 1/2" hole on the front panel. The contacts were very close to the edges of the switch, and he had insulated it from the top of the chassis with some duct tape. I thought that was dangerous and ripped it out.

    I'd like to add a power switch using the existing hole. Can anyone recommend a switch that will fit in this small chassis (I have to use the front because the EFB board uses up all the top real estate), clear the top and bottom, and fit in a 1/2" hole?
    I suggest a solidstate relay, it can be mounted anywhere in the amp, and controlled via
    a DC from the preamp. The hole where the switch is mounted could be filled with
    a rca-connector that is used for the controlling DC.

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    Bob Latino
    Bob Latino
    Bob Latino
    Admin


    Posts : 3262
    Join date : 2008-11-26
    Location : Massachusetts
    • Post n°3

    ST-35 power switch. Empty Re: ST-35 power switch.

    Post by Bob Latino Fri Apr 01, 2016 8:58 am

    The best thing to do (if you want the amp to still have a switch on it) is use a 1/4 inch SPST switch in the hole with two washers to shrink down the hole size to 1/4 inch. Check the sticky at the link below where the second photo down shows an ST-35 with a 1/4 inch switch retrofitted to an ST-35 amp. You could also bypass the switch, plug the amp into a power strip and turn the amp on and off from the power strip.

    Rebuild your Dynaco ST-35 thread

    Bob
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    daveshel
    daveshel
    daveshel


    Posts : 169
    Join date : 2011-11-06
    Location : Tucson AZ USA
    • Post n°4

    ST-35 power switch. Empty Re: ST-35 power switch.

    Post by daveshel Fri Apr 01, 2016 6:25 pm

    I like the idea of a relay - I don't want to use a power strip because I don't want this amp to run when I'm using my others, and I don't like the idea of running that much current through a tiny switch. I've been searching for info about what kind of relay to buy and how to implement it, but I haven't found anything on point.
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    peterh
    peterh
    peterh


    Posts : 1833
    Join date : 2012-12-25
    Location : gothenburg, sweden
    • Post n°5

    ST-35 power switch. Empty Re: ST-35 power switch.

    Post by peterh Fri Apr 01, 2016 6:34 pm

    daveshel wrote:I like the idea of a relay - I don't want to use a power strip because I don't want this amp to run when I'm using my others, and I don't like the idea of running that much current through a tiny switch. I've been searching for info about what kind of relay to buy and how to implement it, but I haven't found anything on point.

    A starting point maybe ? https://www.sparkfun.com/products/retired/10636

    or https://www.ia.omron.com/support/guide/18/overview.html


    Last edited by peterh on Fri Apr 01, 2016 6:38 pm; edited 1 time in total
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    Bob Latino
    Bob Latino
    Bob Latino
    Admin


    Posts : 3262
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    Location : Massachusetts
    • Post n°6

    ST-35 power switch. Empty Re: ST-35 power switch.

    Post by Bob Latino Fri Apr 01, 2016 6:36 pm

    That 1/4 inch SPST switch in that ST-35 rated at 3 amps .. The ST-35 uses slightly less than 1 amp when running. I had that ST-35 in the photo for many years before selling it .. Never had a problem with running that switch. The one at the link below from the "Rat Shack" looks like the same switch ..

    ST-35 power switch. ST-35powerswitch

    Radio Shack 1/4 inch SPST switch

    Bob
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    • Post n°7

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