many higher end prepros exhibit audible hiss. most simply mute it. scott pointed this out in his post (see: analog introduces hiss?, page 1).

many times in the studio, a single coil guitar would ooze unwanted noise. it was simply gated. no one would ever say to get rid of that noisy guitar, because the guitar sounded too good otherwise. end of problem...dead quiet between playing times.

to be honest, if i heard hiss during playback, i would send the 950 back...period.
since i don't (hiss is at 30" with ear to tweeter, not audible otherwise) i am fine with my situation. if i heard hiss during pauses or dead spots, and it offended me, i would consider gating my preamp because the 950 is worth keeping for it's sound/cost.