Long USB Cable OK?

I just purchased an Ultra Fi iRoc DAC (haven't received it yet), and intend to use it with a media PC that has iTunes (I've all my CDs on the HD on Apple Lossless format).

Question I have is whether it is ok to use a long USB cable from my PC to the DAC? Currently my PC is about 18 feet from my Audio System. I can then connect the DAC to my Preamp with a very nice analog pair of ICs (1M pair of Acoustic Zen Absolute - I think retail on those was about $2.5k). Also, can I use a regular length USB cable and an extender (I have an extender already, so am just wondering if I can use that too, without any sonic impairment)?

Alternatively, I have a very long length of cheap analog ICs I can use (and keep the DAC close to the PC with a short USB cable).

I keep the PC out of the way because its noisy and prefer not to have it alongside the audio system and speakers.

Any advice welcome. Thanks!
Ad3dd209 f1c2 428b 9060 a6e7ac9e0ed0outlier
That is a bit long. Any chance you could use optical?
According to Gordon Rankin (Wavelength Audio):
"2m for 24 bit dacs and 3m for 16bit dacs".

Is that for the analog cables, or for usb digital cables from a pc, or for coax or optical digital cables from a cd transport?

-- Al
If your DAC is 1st class and your system is very revealing, you will be satisfied with nothing less than the best short USB cable possible. In my experience, longer IC's are preferable. I have tried optical (allows a very long run,) and its OK, but no comparison to my current Ridge Street Audio 1m USB. Difference is night and day!
Thanks for the response guys. I'll play around with some variations. One upgrade I could pursue over time would be to get a new PC that's quiet, or maybe I can put some noise reduction felt or other absorbant material around my current PC and then position it together with my other gear.