It is very useful and I really appreciate it!
btw I've been listening my Superlux HD669 through my DX50 for hours! I must say what are you saying are true.
at first glance of hearing(does "glance" work for "hearing"?) it sounds a little bit bright as I'm used to dark-sounding iPod touch gen3->fiio L6->Fiio E11 with bass boost 1. The Fiio E11 tamed my iPod's treble and I perceived the mid-bass boost as well as the recessed high as warm, full bodied sounding. However I was wrong.
Upon listening for hours I found that DX50's low bass are actually good on 1.2.8 firmware! mid is somewhat not recessed like the iPod touch + fiio combo and I have no trouble picking electric guitar from playing my messy, muffled MP3 J-pop songs(instrument overlapping all over the place). I also experience the same kind of body thickness sound like you said, the body is really something that thin sounding cans really fit! now my HD669 sounds much more balanced. I was wrong perceiving that every DAP that reproduce the high really well will always be bright sounding.
What I feel lacking from the DX50 is only the vocal, as it feels a little bit laidback, and the sweet female vocal from the E11. Maybe I'm just not used to it yet.
The instrument seperation, detail as well as the soundstage from this little thing is just ridiculous. my iPod and Fiio combo won't be able to sound anywhere as detailed as this thing. I can't imagine how studio V sounds like after listening to this DAP D:
I can confirm this thing sounds warm and good for thin-sounding cans.
you drive your Q701 with medium gain setting? that's weird.. because I'm driving my HD669 on high gain because the dynamics are much better, instrument separation, detail and soundstage are much better on this setting too! they sound a little bit over-sibiliant to my ear on high gain though
I'm loving this DAP to death, the only problems are most of my mp3 song sound less dynamic and refined compared to my loseless songs, the touchscreen are a little bit sensitive to scroll and now I can tell that I have some fake downloaded flacs..