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    VTA ST-70 adjustment question


    Posts : 11
    Join date : 2010-10-25

    VTA ST-70 adjustment question

    Post by Mikeski on Sun Mar 20, 2011 12:53 pm

    Hi All, I completed the install of my low gain VTA board. Everything is great. What a difference. However, there are two pots on the bottom that the instructions say to use an 8ohm load and a 100hz? signal and adjust the pots to make the measurement 0. I think at least. The instructions are not in front of me. I don't have a sig gen. Is there any other way to make that adjustment? Or just leave them in the middle and go on with life. I'm easy that way.


    Posts : 1463
    Join date : 2008-11-30

    Re: VTA ST-70 adjustment question

    Post by tubes4hifi on Sun Mar 20, 2011 1:48 pm

    best to just leave the pot set in the middle, even with all the great test equipment, it rarely makes enough difference at all to hear.
    Bob Latino

    Posts : 2645
    Join date : 2008-11-26
    Location : Massachusetts

    Re: VTA ST-70 adjustment question

    Post by Bob Latino on Sun Mar 20, 2011 4:35 pm

    Roy is quite correct here. If you just set those 10K AC balance controls to their mid point, that is about as good as it gets. Just measure from the center pin to each outer pin and adjust the control so that you have close to an equal resistance from center pin to each outer pin. The reason those AC balance pots should be put on the BOTTOM of the driver board is because once set, you shouldn't ever have to adjust them again. If you put them on the TOP of the driver board you could accidentally reset them instead of just setting the four DC balance pots. It is a good case of out of sight - out of mind. I have set those controls with a signal generator and could not hear any difference in the sound of the amp as opposed to being set initially with a resistance meter.


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