My son has a fairly standard PC with PowerDVD and onboard soundcard that only does stereo sound. He wants to connect this to an av receiver that has a standard optical digital input. Could anyone recommend a simple, relatively low-cost sound card with the appropriate output? My problem is that typical Soundblaster cards have an S/PDIF output socket and I would imagine that these are not compatible with a full-size optical input on the amp. Are there soundcards that do have this output or are there adaptors that connect S/PDIF to optical cables? Any info gratefully appreciated!