When you demo'd the K1XSE was it with the matching PS1 power supply? I've found power supplies to be the key ingredient in audio which is what I like about the K1X + PS1 combo. The D1XSE only gives the option for its internal PSU.
Yes ... I think the key is the mono dacs provides more benefit in this case than the seperate power supply, although the circuit layout is slightly different in the D1XSE also so its difficult to know which is more of a factor. My guess is its the combination of the two.
