No, so long as you have an fibre optic port on your mainboard it plugs into that, with a USB cable to provide power to it. You headphones plug into the DSS2.
It's actually just a digital analog convertor + DSS effects so it's much more akin to a home theatre reciever than a sound card in that sense. While you can run from a sound card into it I'd recommend against it as you'd be negating the sound quality advantage you'd otherwise.