The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all Tubes4hifi.com products and all Dynakitparts.com products


    Power switch (re)location

    Share

    GreggW

    Posts : 56
    Join date : 2015-07-15

    Power switch (re)location

    Post by GreggW on Thu Aug 20, 2015 8:50 pm

    My ST70 is located on a fairly high shelf for safety. I have a couple of curious grandkids that think the tubes are pretty lights. The power switch is difficult to get to, but I always find a way. The unused mono/stereo switch is a convenient location, but I'm skeptical of running AC from the back of the chassis to the front. Recommendations are welcome.....

    peterh

    Posts : 679
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Power switch (re)location

    Post by peterh on Fri Aug 21, 2015 4:03 am

    My recommendation for powerswitch :
    Install an SSR ( solid state relay) inside, connect it in paralell with the existing power switch,
    and install a rca connector that is used for the 3-32V control circuit.

    Then tap your preamp for a DC withing the range ( PAS3 already has a suitable DC), on anything else
    if no DC available, rectify filament and use as control.

    This will give a convenient remote power control.

    An alernative ( not as fun) is to purchase a AC distribution panel where one outlet
    will control the others, connecting the preamp to the controlling outlet will
    enable the other outlets that may be used for the ST-70.

    Don't rewire AC to the front switch !!

    audiobill

    Posts : 270
    Join date : 2014-03-13
    Location : Philadelphia

    Re: Power switch (re)location

    Post by audiobill on Fri Aug 21, 2015 11:17 am

    How about a switched outlet strip of sufficient current?

    sKiZo

    Posts : 1310
    Join date : 2013-04-01
    Location : Michigan USA

    Re: Power switch (re)location

    Post by sKiZo on Fri Aug 21, 2015 2:07 pm

    I'm still kinda partial to my power switch ... ;-}



    Not sure what your issue is with just rerouting the power switch to the spot used by the mono switch? Kinda tight, but seems to me I've seen it done. Wires for mine go a whole lot farther than yours would in a stock chassis, and I've not had any noise issues or such.

    Plan B - reroute all the bias connections to just one of the bias sockets to make room for a power switch there?

    Or just drill a hole in the side of the chassis for a toggle.

    Or just add an inline switch to the power cord and bring that to the front under the chassis?

    Lotsa options, eh. Some that might even work!


    GreggW

    Posts : 56
    Join date : 2015-07-15

    Switches n' amps

    Post by GreggW on Mon Aug 24, 2015 12:05 am

    I read the replies and decided to take another look at my amp. Seems like there are a lot of extra parts in it like a second choke and some extra capacitors. The power transformer has the same height as the one on the 120. The ST70 is a ST120! Never looked at the ST120 on the Tubes4HiFi page as I "assumed" it was a 70. No wonder my electric bill is a little high. Anyway, I'm going to move the power switch to the front and see what happens. If I get negative (60-cycle) waves, it will get moved back. Thanks for the good tips.

    peterh

    Posts : 679
    Join date : 2012-12-25
    Location : gothenburg, sweden

    Re: Power switch (re)location

    Post by peterh on Mon Aug 24, 2015 3:14 am

    GreggW wrote:I read the replies and decided to take another look at my amp. Seems like there are a lot of extra parts in it like a second choke and some extra capacitors. The power transformer has the same height as the one on the 120. The ST70 is a ST120! Never looked at the ST120 on the Tubes4HiFi page as I "assumed" it was a 70. No wonder my electric bill is a little high. Anyway, I'm going to move the power switch to the front and see what happens. If I get negative (60-cycle) waves, it will get moved back. Thanks for the good tips.

    You don't really listen ehh ?

    Luddite

    Posts : 235
    Join date : 2009-02-04
    Age : 66
    Location : Texas

    Re: Power switch (re)location

    Post by Luddite on Wed Aug 26, 2015 6:18 pm

    audiobill wrote:How about a switched outlet strip of sufficient current?

    IMHO this would be the best option (K.I.S.S. principle).  You probably just need a temporary solution until your grandchildren are old enough to have learned not to touch hot objects.  At that point you could rearrange your hi-fi components so that the amplifier is more easily accessible.  FYI, I built an ST70 in the early 90's from NOS Dynaco parts, obtained from Sound Values.  Not only did I locate the power switch on the front, I also located the fuse holder on the front.  Furthermore, the audio inputs were relocated to the rear of the chassis.  These modifications caused no problems whatsoever.  Thanks and...

    Best Regards,
    Charlie

    Sponsored content

    Re: Power switch (re)location

    Post by Sponsored content Today at 10:29 pm


      Current date/time is Sun Dec 04, 2016 10:29 pm