Just got my MKII up and running a few days ago. It’s plugged into a a Niagara 7000 and I am am hearing a slight hum with my ear about 1” from the DAC, however it’s dead silent though the speakers.
I’ll have to try plugging in straight to the wall, but as far as sound quality the MKII is fantastic. I’m running a long optical usb cable from my Mac Pro in another room running Jriver as opposed to ethernet/EtherRegen I was running in the MKI. I’m very happy with the unit so far and has really helped with the last niggles I have with my speakers coincident drivers dissapearing.
still planning on doing the transformer upgrade when available, as it supposedly takes the Dac to another level.