That is not the Xonar card I was recommending. The Xonar "DS" model is a 7.1 audio gaming card. It does have an spdif output, but you will have to do a mod to wire it into an RCA output, like this:
https://www.youtube.com/watch?v=v7CLneUAnRw
By the way, this guy is a total amateur with regards to soldering. I'm cringing just watching him do those solder points! ack. The "DS" model does not have the two crystal clocks for the proper audio sampling right timing. It can be used, but the Xonar Essence "ST" model is highly superior.
It does not look like there are any Xonar Essence "ST" cards on ebay right now, but they do come up for sale fairly often (there have been 3 sold in the last month).
There are some "STX" PCIE cards available right now on ebay, such as this one:
http://www.ebay.com/itm/ASUS-Xonar-Essence-STX-/253196117652?epid=77162604&hash=item3af3aa2694:g:rokAAOSw6HJZ2RY-
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Take a look at the details on this page:
https://www.asus.com/Sound-Cards/Essence_STX_II_71/
This is the newest version of the card, the "STX II". It appears that it uses TCXO clocks, which are highly superior to the normal crystal clocks in the older ST/STX versions. But it's a new product and it's going for about $250, such as this:
https://www.newegg.com/Product/Product.aspx?Item=N82E16829132072&cm_re=sound_card-_-29-132-072-_-Product
Hope all this info helps.