There are some interfaces which claim lower ADAT clocking jitter, but I've used a lot of
ADAT gear and never had problems in that respect, only with some dodgy optical leads
Just need to make sure about setting the correct clock rate
at both ends and the clocking master/slave so things sync up correctly. I assume you still
plan to use your ADA8000 for D-A duty on the 1820M's ADAT out, so be mindful about that
and about S/PDIF settings too.
IIRC, the 1820M supports 192 kHz on ADAT,
although IIRC the Octopre is limited to 96 kHz. Still, that would allow you to record 4
channels at 96 (or 88.2).
If possible, try to listen to an Octopre before you
decide. And if you only want to record at 44.1/48 (or use any outboard processors), you
might give a listen to a Presonus Digimax also, some nice pre's in there and some models
offered inserts. M-Audio also offered some decent 8-channel pre's with ADAT out. Lots of
options out there (and ADAT patchbays too, so one can even indulge