Again, I keep hearing that I need to have a USB or Firewire in the vocal chain in order get the BEST conversion from the ADI-2. Up until not I've had the ADI-2 connected to my Mac-mini via Toslink (optical). And I have "digital" chosen for the input/output device. And I have the Pre mic out going into the ADI-2 analog in (via TRS). This is how I've had my set-up for the last year or more and seems to sound pretty good, though I'm not sure this gets the best conversion from the ADI-2.

I tried adding an MBOX3 (regular) to the ADI-2 via S/PDIF ins/outs:

Amadeus Pro DAW:
MBOX selected as input/output: No signal from the Pre, just the MBOX. Although I see levels on the meter, nothing from the mic changes the levels and I get no sound in.
DIGITAL selected: I have to playback in OPT...sound is super slow with clicks...something is definitely off.

In system sound preferences I have three choices:
Digital
Digital Core Audio
Avid MBOX

I tried Digital and MBOX and get the same slow, warbly sound. When I select Digital Core Audio, it just defaults to the MBOX.

In PT9 Hardware Set-up, I only get a "Pro Tools Aggregate I/O" and can select the Set-up App, Midi Set-up. From Midi Set up when I select "Digital In/Out" and hit record, I get a spinning ball and everything freezes up.

I don't know if there are separate MBOX settings somewhere.

So, should I put the MBOX in the chain? If so, how? Thanks!