Just got it.. So far, so good no noise, no scratchy pot, tube sits a little loose(very easily pulled out), but maybe that's just how it is?
@ max volume, song paused there is no audible hiss, or noise from any headset :)
HD58x, HD800 and To400 all get uncomfortable at around 8-9 o'clock(track dependent), no distortion. HE4xx gets uncomfortable at around 10-11 o'clock(track dependent), no distortion.