dfkt> recieved yours yet? Would gladly hear some opinions what you think about sound quality of ZO2 compared to ZO1 which I know you really liked.
It may have to do with the volume control too I suspect, as it appears to sound better the higher I set volume on ZO2 and a bit lower the source volume. This is no different than other amps I've used though, especially FiiO E5 sounded horrible at very low levels, distorting a little etc but that's a common thing with amps in general.
I seem to get the best result with ZO2 set to max vol lvl. At this point you could start debating how important that volume adjustment is in case I'd just keep it at max level all the time anyway. :P Maybe this is what really made ZO1 sound so nice, the lack of volume control? I mean amps doesn't usually lack that so it's kind of hard to base an accurate opinion regarding this.
EDIT: Unlike some else said I have no trouble using max contour lvl without getting distortion but I've set ZO2 to max volume and the windows volume control at like 20~25% for these HTF600. The cups vibrate like mad.
EDIT2: I'm not so sure there's any noteworthy difference in sound between the ZO1 as long as ZO2 is set to max vol lvl. I will give ZO2 more time before giving further comments on the sound.
EDIT3: The lowest level on ZO2 seems to make the bass a tiny bit more punchy than without amp. I kinda miss that ZO1's lowest level I used to use sometimes just to be able to critically listen for distortions and such in a track as it reduced the bass slightly on this level, useful for my bassy headphones.
EDIT4: Especially in this track you notice even at the very lowest contour level you get a boost in bass as it seems to happen mostly down at the very deep frequencies. This track plays a constant low frequency bass around 20~35Hz. Seems like ZO2 lowest level about the same or very close to ZO1 = first boosted lvl in bass quantity. Probably talking about some 2dB or so.
Edited by RPGWiZaRD - 11/9/11 at 6:13am