Ground Loop Issue

[Brillo]

I purchased a used Bottlehead DAC with Bottlebat power supply and just installed it in system (Mac Mini>DAC>BeePre>Paramounts).  I'm having a massive ground loop issue whereas previously I had none.  The only change is swapping of DACs.  I haven't found another thread where this issue has been raised, so asking for insights from the forum on ways to combat this.  The issue persists whether using battery power or the wall wart.  It's playing music, but overwhelmed by the volume of buzz.  No buzz when I disconnect the RCAs.  Thoughts? 

Chris

[Paul Birkeland]

If the DAC is plugged in and powered up but not connected to your computer, is the noise still there?

[Brillo]

Nope.  It stops as soon as I disconnect the USD cable. I have a toslink cable, but the male end doesn't seat fully into the DAC, so need to find another.  Is there a simple fix for the USB?  It's working fine otherwise - the Mac recognizes the DAC and reads the bit rate, no problem.
   

[Paul Birkeland]

I would recommend trying a different computer.  I have never experienced what you're describing, so I wouldn't know where to start!  (The toslink cable is likely going to be the way to go though)