Edited by dalb - 11/20/13 at 12:25am
There is a very mild transformer hum. Sounds normal to me. I don't hear it very often, think there was a lot of exaggeration on that or a few really bad ones that got everyone so fired up.
They go really well together. Although I don't have a lot of experience with different amps so I don't really know much about synergy. the Asgard 2 drives the HD600s easily. Have the volume knob at about 10-11 o'clock