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    Cooling Options for ST-120

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    arledgsc

    Posts : 340
    Join date : 2012-11-30
    Location : SF Bay CA

    Cooling Options for ST-120

    Post by arledgsc on Thu Mar 21, 2013 10:56 am

    The ST-120 seems to run on the very warm side and with summer around the corner thinking about cooling options. A lot of heat builds up in the power tranny while the already hot running Weber SS rectifier and capacitor can are in very close proximity (and the KT88s). I'm most concerned about the cap can baking. As a general rule in electronics for every 10 deg C component temperature rise reduces its life in half and hold especially true for electrolytic caps.

    It seems normal convection can't remove all the heat from the amp. Experimenting with a desktop fan blowing gently on the power transformer rear reduces its temperature dramatically to almost room temperature. It doesn't take a lot of air movement but this fan is too loud so need something quieter. Anyone have a other solutions to consider? Thanks as always... Scott

    Bob Latino
    Admin

    Posts : 2411
    Join date : 2008-11-26
    Location : Massachusetts

    Re: Cooling Options for ST-120

    Post by Bob Latino on Thu Mar 21, 2013 11:24 am

    Hi Scott,

    All tube amps are made to be run "hot". The transformers, quad cap and all the parts inside can take the heat. The heat will not shorten the life of the amp. See the link below on a previous post on the temperature of a VTA ST-120 amp.

    VTA ST-120 temperature link and photo

    Bob




    hawaii.ken

    Posts : 157
    Join date : 2012-01-31

    Re: Cooling Options for ST-120

    Post by hawaii.ken on Thu Mar 21, 2013 11:33 am

    Maybe something like this:
    Lasko Clip Stik

    arledgsc

    Posts : 340
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: Cooling Options for ST-120

    Post by arledgsc on Fri Mar 22, 2013 11:16 am

    I'm not trying to ruffle feathers but just asking for cooling options for my environment. The temperature readings indicate at an ambient temp of 69 deg F the cap can outer case measures 129 deg F. What if the ambient temp is 20 deg F warmer? The can cap would be about 129 + 20 = 149 deg F (65 deg C). Cap life would be 20,000 hrs. @ 65 deg C in this case. I'm just going by the Authenticap datasheet at the rated ripple current (pg 2).
    Authenticap Datasheet

    tubes4hifi
    Admin

    Posts : 1291
    Join date : 2008-11-30

    Re: Cooling Options for ST-120

    Post by tubes4hifi on Fri Mar 22, 2013 2:05 pm

    that's about 14 years of life if you're lucky enough to spend 4 hours a day listening to them!

    sKiZo

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

    Re: Cooling Options for ST-120

    Post by sKiZo on Thu Apr 04, 2013 1:43 am

    Laptop cooler?

    I got one of these at Wallyworld back when I had an HTPC that was toasting in the hot August doldrums. Too cheap here to run AC ... 8" fan moves a lot of air but is dead quiet.



    You could probably just prop one up behind the amp. Then all you need is a 5v power source ... they make wall warts you can plug the usb cord into ...

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