Hi I think you are making this too complicated. You want to compared two sets of speakers: set A and set B. First any SB outputs two sets of digital (optical and coax) at the same time (see http://forums.slimdevices.com/showthread.php?t=65692&highlight=outputs) so you can run identical A+B side by side.
However to switch from A to B and B to A (many times) you need either an amplifier with a A B speaker set button (quite common) or a switch on the digital out (at the DAC or to the DAC). Many DACs (even cheap $100 ones) have digital input switching for optical and spdif (coax). Ignor USB, as already mentioned there is no usb output). So you can switch between the near identical optical and coax outputs. Lets say you are obsessional and want to compare coax (spdif) with coax (spdif) without bringing optical into the equation you can use a coaxial cable splitter ( a high quality one is sold by QED (I think as subwoofer Y cable) which works perfectly splitting one digital output into two (with no quality loss). does that help? -- ajmitchell http://www.last.fm/user/ajmitchell ------------------------------------------------------------------------ ajmitchell's Profile: http://forums.slimdevices.com/member.php?userid=800 View this thread: http://forums.slimdevices.com/showthread.php?t=87592 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles