Giving the HD600s a good level e.g high gain (as others have agreed) and just over half volume level e.g 75db loudspeaker listening level and depending on music mastering loudness results in a full and quite satisfying listen. On normal level as well as very low levels/quiet critical listening it becomes a little clearer that the Hd600s might not be reaching their full potential.
The overall fequency reproduction seems well balanced with a good lower freqeuncies although it feels a touch slow overall and in bottom end tightness. Being very critical the upper mids can also be a touch hard as noted from listening to various recordings from Beck 'Everybodys gotta learn sometimes all the way to Prokofiev 'Peter and the Wolf'.
The soundstage is very good with the right recording (recordings that exibit good soundstage in the first place). Depth and separation is decent although on busy recordings separation becomes harder to discern and muddled up.
On the whole the DX-50 does a reasonably a good job of drving the HD600 on hi-gain. A headphone that most people agree needs a good matching as far as power/amp to get the very best out of them.
As I said before though, I never intended the DX-50 to match up to my HD600.
Edited by polyrhythm - 5/11/14 at 5:50am