I'd have to look at the block diagram in a service manual I have for the SC-57 & do give you my interpretation of the circuit paths. the 57 has similar design topology. when I get a chance today or tonight, I'll take a look.
are you not getting 5.1 out and checking or asking before you try it?
I was thinking about ordering Turtle Beach XP400 Dolby surround headphones which take a 5.1 digital optical input, and it would have been convenient for me to just take that from the AVR's digital output. I guess I'll have to either get a toslink switch (since my output devices have unused toslink outputs) or an hdmi audio extractor to get a toslink signal out of one of the AVR's hdmi outputs.
Added: Since the AVR doesn't ordinarily pass audio to its hdmi outputs, I'm going to get a toslink switch to feed the headphones.
Edited by GregLee - 3/19/14 at 11:59am