Just been trying to get tv sound through my hifi. I attached the tv via optical to my 740c digital input to use the dac in my cd player and all I got on the hd channels was a constant clicking sound. The SD channels worked fine. I then tried it via RCA into my amp and the sound on the hd channels worked. Why can I not get any sound on the hd channels via optical? Is it because of the signal output on the hd channels? Any help would be great.