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29414Re: V9 output to audio card?

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  • Ken
    Jan 1, 2009
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      OK, it's getting better now - OR maybe I'm just more confused.

      By "mains frequecy" you mean the 60 (or 50) cycles of the power line?
      A "lowish" value (such as in the pF range?) will loook like a brick
      wall to the low freq while allowing the "spiky" USB signal to pass....
      Is there any signals as such on the ground wire of the USB connection?
      AND does the ground wire not need to be a DC ground that would be
      blocked by a capacitor? I guess I am still confused.... I'm starting
      the new year in my "normal" state of mind- CONFUSED.

      OR are you suggesting putting this "lowish" value capacitor on all the
      USB wires to isolate them to prevent any ground loops?

      Thanks to all for info shared in these forums.

      73 de Ken H> K9FV


      > Well, the current through ground loops is basically at mains
      frequency and
      > its lower harmonics. A lowish value capacitor will have a highish
      impedance
      > at these frequencies so little current will flow.
      > The capacitor offers a relatively low impedance at the higher
      frequencies so
      > passing the spiky USB signal. In my case the impedance of the ground
      > connection must have been high enough to suppress this signal.
      >
      > 73 Alan G4ZFQ
      >
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