Optical Shomptical! No joy in Mudville.

[MIDI Life Crisis]

No matter what I do, I cannot seem to get spdif optical connections to work.

SETUP

Mac Pro with optical in/out
V-Synth with optical out
MINI Disc with optical in/out
Focusrite Saffire Pro 24 DSP with optical in

What I've tried:

A: V-synth to Mac, MINI Disc, and Focusrite.

B: MINI Disc to Mac & Focusrite (pre-recorded disc)

C: MINI Disc to Mac

Result:

A: No signal shows up except to the Mac, which shows the signal but is not outputting any sound.

B: Nothing shows up when switching to record (monitor).

C: No signal present at Mac.

What I've tried:

All sample rates, all sync options, all IN/OUT combinations.

What puzzles me is that the Mac Audio preference, when set to optical in, shows the V-synth signal attenuating, but I hear nothing.

[Frodo]

Optical = built in. Hmm.

What DP settings do you have in Setup> Configure Audio System> Configure Hardware Driver?

What settings do you have in your output bundles?

I know you said you tried them all, but there must be some combo overlooked - or- there's a hardware issue or an optical compatibility issue.

Didn't you have this working before?