Well I'm going to shoot of this thread quickly hoping someone has some experience with this unit.
Today I received the M-Stage DAC from Matrix Audio that I bought through MassDrop. The sounds is quite good and more of an improvement than I was expecting over my Focusrite Saffire Pro 24. However one thing I absolutely hate is noise in my audio system. At normal and loud listening levels my setup is silent with no static or any noise for that matter, if I crank up the volume though I get some serious hum through the system which only exists above high volume levels. This obviously doesn't really affect my listening as there is no audible sound at any sane listening levels, I would like to eliminate this noise if possible.
So far I've tried lifting ground on either device but never on both. (I'll have to dig out a cheater plug from my garage to test both at the same time.) I've tried removing the USB cable but the noise persists. It's not a short or wrong connection in my cables as it is identical with any cables I try. My HD650's are less sensitive to the noise but it is still there.
I'll be continuing my search for a DAC that really does it for me. (I think the Schiit Bifrost is next for me.)
Anyways, it really doesn't affect my listening at all because I would ruin my phones and go deaf if I had it loud enough to hear the noise with music playing. There is no noise with the DAC powered off.
For reference here's my equipment list.
MacBook Pro (Pre-Unibody 2008)
Matrix M-Stage DAC
Meier Corda HA-2
Beyerdynamic T70 / Sennheiser HD650
Unless I did something wrong I'm guessing it's either too hot of a signal for the Corda which is picking up extra noise from the circuit in the M-Stage DAC or it's a faulty DAC.