The oppo 105 has Asynchronous USB in, it will work fine, you'll need wasapi or KS output on JRiver. If you don't buy the oppo, you will need to do as Steve mentioned and get a good USB to spdif converter for your Dac magic, you need your usb out on your Computer to do the conversion before the dac, so you will need an asynchronous converter. There are plenty available, Steve's is the best and most expensive. I can recommend converters from $100 or so up to Steve's off ramp. I would also add another 4gb stick of Ram to your notebook. If you have 2 1gb sticks, replace 1, if you have 1 2gb stick add the 4gb.
I hope this helps, Tim
I hope this helps, Tim