Ha, that's strange, but you know what, the only difference I can tell between my Xonar DS/ALC888/e7 is the boomier bass on the e7. Compared to the laptop onboard there is no contest however as it was horrible in every way, so I do not regret my purchase no matter what.
I have no idea if it's the AMP or DAC but it is slightly annoying to me. The EQ is set to 0 but I've been wondering if it could be bugged or something? I've tried using it and couldn't really notice a difference between 0 & 1, above that it kept getting worse though.
Did all those tests rather quickly mind you and I used a mere Superlux HD668b (with velour pads) and some old Pantronic IEMs. The latter sounded great with the e7's bass but the former did not, it felt boomy.