Perhaps one of the greatest mysteries in the art of Hi Fi is how the separation of instruments and voices is manipulated from inside an electronic circuit.
There is certainly no measurement we know of that accounts for varying degrees of separation, yet the difference is significant.
If you're lucky enough to have both an MK1 and MK2 DirectStream DAC on hand, you can easily make this test for yourself. The MK1 sounds fine, but compare the two with this one aspect in mind and I think you'll be stunned. Air, space, and three dimensionality between instruments and voices are enhanced to the point of shaking one's head in disbelief.
But how? We know that power supply improvements often have a direct correlation and we also know that in some circuits, the open-loop performance too has major impacts.
But this is a digital circuit. Yes, there have been major power supply upgrades in the MK2 and, perhaps, that accounts for some of the improvements. Yet, when Ted releases a new firmware, that see-through separation is changed as well.
The mysteries continue.