I 've been an iBasso D-Zero owner for 5 months and recently I managed to get fantastic sound out of it.
I want to share my conclusions/suggestions with other iBasso owners in order to help them get the full potential of their device:
1. I good burn-in is needed for both DAC and Amp sections.
Something that initially put me off this product was some upper-midrange edginess in the DAC section.
However, after a good burn-in (about 100 hours) the problem disappeared.
2. Don't use Foobar 2k because it sounds thin! I 've tried every configuration in Foobar: WASAPI & ASIO plugins, upsampling to 48Khz without being able to get a full sound. The sound in Foobar gives you the impression that you hear everything at a distance. At the other extreme is Winamp which sounds much fuller and wider than Foobar but everything comes too forward like on your face which is also a put off. I started installing and trying various audio/media players to find the best one until I came across "J River Media Center v19.0.54". This one sounds perfect (in presentation, soundstage, everything!) and of course outperforms every other music player I've tried. I use it in WASAPI mode and now look no further in software improvements!
Here I would like the opinions from the experts because I 've read in a forum that every audio player should sound the same and everything else is placebo effect etc. I totally disagree! For instance I get much different audio between Foobar and Windows Media Player even when both play with ASIO4ALL!
3. Replace the damned stock mini USB cable with "Kimber Kable mini BUS CU"! I know this is expensive (maybe half of the price of iBasso D0) but you will be blown away when you hear the difference. This review also suggests using that cable.
In conclusion, after using "J River Media Center v19.0.54" to play the music and having replaced the stock mini USB cable with "Kimber Kable mini BUS CU" my iBasso D-Zero got a real sound-lifting and now sounds AWESOME! :-)