Danville supplies the dspNexus with DAC options. The unit that Vance tested used the standard AK4493SEQ DACs which are good, but not our best.
The most popular configuration now is based on AKM AK4499EX DACs. IMHO, these are the best semiconductor DACs available. If I thought something else was better, I would use those.
FWIW, I do not follow the reference design circuit suggestions for the supporting circuits and I think we get better results.
Obviously, everything starts with good ingredients.
Al Clark
Danviile Signal