First of all, your headset is not the issue. Jus patch the sound out from the card as explained above. If you want to run both computer speakers and Stereo amp you simply buy a 1/4" splitter. You are confusing yourself here. The headset and sound out are not connected directly. If you want to install a USB soundcard, that would accomplish the same thing....you would still need to patch to the stereo from a separate source different from the headset.
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