Hello,
I just received mine today, but when I'm using it with an external microphone (AT-922, SoundProfessionnals binaural), I've got a ground noise.. I'm selecting the option "power on" when I plug the microphones, this should be ok..
Did somebody have this issue?
I think my unit might go back to the shop..

here's a link of a wav recorded when I plug my AT-822, I'm just moving it or the cable near the D50...
http://www.sendspace.com/file/jxnt0g