thanks for all the replies everyone. i remembered later that "common
mode" often has to do with hum on an ac line, but these descriptions
were very clarifying.

i haven't heard the box yet. i'm doing lots of organizing in july.
and then starting in august, i'm going into listen/buy mode.

there are two things that "concern" me about this new emu box. one:
the clock..how good could it be at this price point? that can be
solved since it has word clock input.

but the second concern: the power on the breakout box comes from the
ethernet cable (there is no ac mains cord on the breakout box). how
much juice can an ethernet cable deliver, and isn't it a bad idea to
have power and digital signal going down the same line?

i guess a third concern would be the quality of the analog circuits
surrounding the converters.

but i think it's cool that emu is using the top of the line converters
that the expensive digi boxes are using. and the layout of the box is
very appealing.