Hiss
I think the hiss is normal if you do not have your POD's S/PDIF outs connected to the Audiophile's S/PDIF ins.
I get the hiss too, when my synthesizer's digital out cable is not connected to the audiophile. I speculate that the audiophile is attempting to relay or play a signal that it is supposed to be linking up with, but if the other connection is not there, the hiss happens.
Create for yourself two different profiles in the Audiophile's sound card. One for digital recording S/PDIF, and another for analog recording.
And do make sure that when you make the S/PDIF profile that you use the correct clock like the other person just wrote. In your case, more than likely, your POD has a clock, too, and when you are recording stuff from your POD into and thru the Audiophile, the Audiophile needs to find the link speed and set it according to a source's clock. It the speeds are not the same (i.e. 44.1, or 48, or 96...whichever) then you will have playback problems of speeding up and slowing down which will make you scratch your head. lol
But I think the hiss is caused when you tell the Audiphile to use S/PDIF, but you do not have the other connection enabled (the POD).
As soon as you switch back to analog, the hiss goes away.
Todd