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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


    1st ST 70 - Low Volume

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    Russ

    Posts : 2
    Join date : 2011-02-05

    1st ST 70 - Low Volume

    Post by Russ on Sat Feb 05, 2011 8:58 pm

    Ok, I'm new here so it may take a little while for me to catch up and I won't be insulted if I'm told that I need to find a more elemtary forum so lets get started. I just got my first ST-70 and set it up to check it out. After replacing one of the the bad 7199 tubes which got rid of an annoying buzz in that channel it played ok except for the volume seems quite low. I say this because I also run a Mcintosh MC240 and though I don't expect the ST-70 to match up, it only produced about 50% of the volume of the MC240. Any suggestions where I start looking?

    Bob Latino
    Admin

    Posts : 2378
    Join date : 2008-11-26
    Location : Massachusetts

    Re: 1st ST 70 - Low Volume

    Post by Bob Latino on Sun Feb 06, 2011 8:33 am

    Hi Russ,

    If the low volume is common to both channels then you have to think of something that is common to both channels. Usually the high voltage DC power supply is common cause of low volume on BOTH channels. This includes the rectifier tube, the quad cap and the resistors on the quad cap. Go to the web page below ..

    Dynaco Tube manuals

    and download the ST-70 manual. On page 9 of the manual there is a voltage check for the stock ST-70. Do a full voltage check on your amp and let us know what you find?

    Bob

    Russ

    Posts : 2
    Join date : 2011-02-05

    Voltage Checking

    Post by Russ on Sun Feb 06, 2011 4:55 pm

    Bob
    Thanks for your reply. I did download the manual and I will go through the voltage checking procedures. I'll let you know what I find. Thanks for giving me a place to start.

    Russ

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