I haven't struggled for so long with a problem in many moons.
I am trying to do my first surround mix project (post production) and I THOUGHT I had it all figured out.
 
In prefrerences, I can see all my adat outputs.  In the Surround section, I select what I presume is the order of speakers.
I connect the adat outs (9-16) from my profire 2626 to the adat input of the Sony or Onkyo surround amp (I've tried both).
No dice.  No sound, actually.
Now I'm starting to think that spdif and adat only carry encoded signals to the surround amp.  I thought only the spdif did that.
 
I am ignorant about consumer surround (or any surround for that matter).
 
help.
 
 

Unless things have changed since I was in the hi-fi business, those optical connectors on your surround processor are not ADAT inputs.  They are in fact optical S/Pdif ins.  To feed those with a surround signal you would need to be sending a Dolby Digital AC3 (or DTS if your unit supports it) encoded digital format.  What you are trying to do will not work.
 
If you have 6ch analog inputs on your surround processor(s), then you could feed analog outputs from your 2626 (assuming it has enough outs) to that input.