I bought a sound card for my PC last week that has digital optical input. Today I tried to hook it up to the digital optical output on my Denon 1803 and to cut a long story short it doesn't work. Its not the sound card because if I hook up my optical sources (DVD or CD) to the sound card input directly, then it works a treat. The only thing I did notice was that, looking at the end of the cable when it is conected directly to a source, then the red light dot at the end is very bright. If I look at the brightness of the light at the end of the same cable when it is connected to the output of the Denon 1803, it is about half as bright. Ideas anyone?