>>There is a place marked L10 which is directly in line with the AES OUT signal pin from the motherboard and the output connector where there's nothing-<<
is there an AES-type signal at where L10 ought to be, at least?
a component with "L" would usually be an inductor; can't think why there'd be an inductor in line with the AES output unless the actual signal is a bit ringy or there's some HF noise in the unit that e-mu felt need calming down a bit.
of course, you could just go analogue... :-)
duncan.