@sls883 @mattw73 I guess the problems lies in the pickiness I have imposed on the gears and different expectation of the term 'layering.' In my book the term 'layering' includes the followings: 1) Depth - front-to-back placement of sounds; e.g., vocals close, drums farther back; 2) Height - perceived vertical location, e.g., cymbal/voice sounding higher than bass; 3) Width left / right placement across the soundstage; and 4) Separation - clarity and space between each instrument or sound source.
I could hear the distinct front-to-back sound level differences of instruments through the µDAC—e.g., on tracks from Modern Cool by Patricia Barber. Nevertheless, the edges of notes aren’t as well defined as with the D90, which results in a diminished perception of depth when compared side by side. The µDAC’s presentation tends to be fuzzier and coarser around the edges, filling the space between instruments and masking the sense of separation.
I went back to some reviews and noticed that most of them described instrument separation and layering as distintive qualities and hence separate aspects.
I guess I just prefer the D90 Discrete’s presentation much more.
Just found a Gustard X26 III in 'very good' condition at a discounted price and fully refundable. This time, I’m taking a safer approach to auditioning. Like you said, paying over $100 in return penalties is questionably worthwhile.