From memory, this specific SFD mk2 unit (with the Telefunkens and PCX upgrades) sounds like a scaled down Rockna Wavedream, even more than the Wavelight. There are tonal similarities from mids to highs (not as slammy or hefty), the giant headstage (but imaging isn't quite as precise). Obviously not anywhere as resolving as the Rockna Wavedream. Yggdrasil A2/OG is just different. However, this unit was almost a straight drop in for the MIL-B from a tone and timbre standpoint, maybe a bit more air with the Telefunkens. The MIL-B is has more heft and is more resolving, but surprisingly not by much. I am actually surprised how good this ancient DAC holds up (the one I owned before with the level 1 mod wasn't anywhere as good, but I think there could be more differences in the modules). I may drop in some Soviet 6N23P-EV for a darker sound. I believe @Carlos CPA may have moved up (reason why he sold this fine unit). Maybe he can chime in a bit.