I guess you mean the isolation being internal...... That's a nice idea, except for one little problem- Much of the RFI goes through on the common side......... So if you use a coax with isolation inside the DAC, for example, much of the RFI from the transport will still get through via the S/PDIF shield and then the DAC chassis. (This is why I don't like plugging analog devices into the same outlets as the digital devices.)
Now if you can somehow do this with a balanced line (AES/EBU), it should work..........
