I'm not a huge fan of Audio GDs 1704UK DACS. They are very good DACS no doubt as they are detailed but they are very laid back. They have a darker presentation and dynamics is not their strong suit.
If you own a system that is decidedly not laid back or neutral on its own than the Audio GD 1704 DACS will be a revelation. If your system is already laid back and neutral (like Audio GD amps and preamp combos) adding a Reference 7,5 or older DAC 19 varieties to the mix will likely put you to sleep. Trust me, I tried.
It wouldn't surprise me one bit if Audio GD 1704 DACS are better performers in headphone systems than they are in speaker set ups. Headphone set ups are always more forward sounding than speaker set ups no matter what cans you are using.
Completely agree. I had to swap opamps in my Auditor to be able to enjoy my Ref 5. Before it was just too dark and not musical enough albeit very detailed.