Basically (theory crafting):
1. Any headphone below 50-70 Ohms using the headphone out on the SBZ will run into problems (though not necessarily on the ZxR). The AD700 (the gamers cheap top headphone for positional audio) is 32 Ohms. Not good. Thing is I've read posts where people have been happy with the SBZ/AD700 ????
2. Using the RCA's/ Line out to an external amp in Speaker Mode with a very low output impedance headphone amp would alleviate the problem (for stereo anyway and this'd be perfect). Caveat being: it destroys any virtualised 3D audio for gaming and maybe movies if you want to use SBZ Pro using stereo headphones because you have to select Stereo Speakers and mimic headphones badly. This is also my question for SPDIF out.. can you select either Speaker and Headphone output or just Speakers to avoid this crap?
3. All that's left is double bloody amping the headphone out. Lob a very low gain amp on it (I've read that people have done it on the SBZ with no distortion, ie the Magni or 1x gain 02. Even a dirt cheap FiiO E5 could do it maybe??). That means you get an amp with 1 Ohm or less impedance so low impedance cans will work without distortion. Caveat is - it may distort the SQ because of double bloody amping.
Groan................ Anyway.. the SBZ plus an $100-140 amp means I might as well get a ZxR, or a SBZ OEM> Spdif > DAC/AMP (see the end of question 2). The ZxR/STX both seem to power low impedance cans well anyway, especially the Fidelio X1 which I want, even though there's a slight hiss with nothing playing at high volumes. Just worried about the above poster who's getting **** audio through a supposedly decent (and presumably common) setup.
Edited by SaLX - 10/16/13 at 8:09pm