Originally Posted by melterx12
EDIT: I tried playing music while turning full range setting on and off and do not notice any difference whatsoever, so I do not think it is that.
I would guess why the line output is a little more clear is because it is a more direct path straight from the JRC2114D, no heaphone amp, so the heaphone amp is apparently not transparent on this card. Good that your phones are so easily driven you can use that output. Personally I believe the most optimal solution would be to use a high class headphone amp connected to the line out, instead of the built in headphone amp. The potential for really high end sound seems to be there, as the aforementioned russian site could barely hear a difference between the Creative Z and a several times more expensive EMU 1616 using line out played back through high end gear. The same thing applies to Xonar ST/STX afaik, they sound better from their RCA-outputs than from their headphone amp even though the headphone amp is what got them highly acclaimed.
Anyway, I just received a Creative Z which I will put through it's paces in a few days. It's meant for my gaming box which is current high end hardware and Win 8, my box for music playback running Linux already has a Xonar ST so it will be easy to compare. I also have Xonar DX, Xonar DG, Audiophile 2496 and X-Fi XtremeGamer if I want to put my observations in perspective.
One interesting sidenote is that my sample of Creative Z also has Nichicon Fine Gold caps in all positions, the same as in Xonar ST, I suppose I'm lucky