I assume your system is computer based. MS or Apple ? I am currently running XP via USB to a Fubar ll DAC in to Audioengine A5 powered speakers. A reasonable upgrade would appear to be the Citypulse or possibly a Promitheous DAC. I read up on your Citypulse. Looks very promising for the money.
Citypulse Audio DA2.03e II vs. Benchmark USB DAC1
I had recently bought a Benchmark USB DAC1... it was good, but without a power switch, or a remote, it was always on & overall, I didn't think it was worth $1300 ... I just received my Citypulse Audio DA2.03e II USB DAC & i got to say, it is AWESOME! It smokes the Benchmark in every way!! I run it directly into my AMP & bypass my PRE. The sound is UNREAL & the quality of the unit, honestly, you would never think it was Chinese... Even the brushed aluminum remote is nice! For $550 from audio magus dot com, there isnt a better USB DAC on the market... (Using Sunfire pre & amp with B&W 804 speakers & now a Citypulse DAC)