What are you trying to do exactly? Your question is very poorly written and I don't understand all of it.
Here is the setup I have. Perhaps it will work for you as well. I have my 5.1 PC speaker system plugged into my motherboard. I also have a 15' optical cable plugged into the onboard sound card and my 5.1 home stereo system. Using VLC I output the audio for DVD/video files over the optical jack. This allows me to have the kids or wife watch a movie over the home speakers, while I game with headphones. If you are trying to do something similar that's all you need. No adapters needed.