primare cd31 with Dac

I currently own a cd31 and I am thinking of buying an outboard dac. My main motivation is to stream computer audio, but I also may want to use it with my cd31. Does anyone have any opinions on an outboard dac? How much would I have to spend to best the primare's internal dac?

Any input would be welcome. I enjoy female vocals and live acoustic music.

Many thanks