USB2.0 is specified for a maximum cable length of 5 meters, or about 16.4 feet. You might get away with 18 feet, if you obtained extension cables that add up to that distance. If not, you could put a powered usb hub somewhere in the middle of the run, and that should work fine.
I would not put the dac near the pc, and run the analog signals through a long cable. My main concern would be that digital noise generated by the pc would couple onto the analog signals. And of course there is also the possibility that the long cable itself could degrade the analog signals, for instance by the cable's capacitance causing a treble rolloff if the dac's output impedance is not low enough to prevent that.
Regards,
-- Al
I would not put the dac near the pc, and run the analog signals through a long cable. My main concern would be that digital noise generated by the pc would couple onto the analog signals. And of course there is also the possibility that the long cable itself could degrade the analog signals, for instance by the cable's capacitance causing a treble rolloff if the dac's output impedance is not low enough to prevent that.
Regards,
-- Al