in that case, it is not the O2 that drives your speakers...what your speakers "see" is just the output of its internal amp..no matter what you put before the internal amp...unless you remove the internal amp, it will become unecessary for you to put O2 in the signal chain. in which case I dont think o2 is capable of driving a desktop speaker. I recommend removing the O2 and use it for something better
Haha, yeah, the O2 is only there for convenience sake, as my headphones are connected to a signal mux. So what's actually going on is this.
-> Desktop Speakers
Xonar DX -> O2 -> audio switcher (makes it so I can pick which device my audio goes into) -<
This way I can switch back and forth with a simple twist of a dial!