If I get this right:
The unbalanced ADI-2FS's SPDIF OUTPUT is connected to the balanced ADI-2 Pro's AES INPUT?
I tried with another sources, to make use of the AES's galvanic isolation.
Didn't work at any samplerate.
The 0.5V SPDIF level is simply too low to drive my ADI-2 Pro's AES here.
I even connected an oscilloscope to check the level:
Due to the 110 Ohms AES termination (instead of SPDIF 75 Ohms) the SPDIF delivered even higher ca. 0.7V.
So my ADI-2 Pro's AES input works within specs, demanding 1V (manual page 67) - unfortunately, as lots of AES inputs works from 0.3V up.
I didn't take the effort to wind a little transformer (not a big deal), but switched to TOSLINK optical.
I have no music higher than 96 kHz samplerate.