I don't think I have musician's ears but I get really annoyed by the noise. I wonder whether I just had a bad unit or it is a universal problem. Could you guys try this? Put on your earphones, enable any of the preset audio effects (go Settings -> Sound -> Media audio effects -> Wire stereo devices -> turn on any effect under Surround or Equalizer), then listen to some light music. Do you also hear noise? If not, toggle audio effects on and off. On my unit, upon turning off all effects, the noise goes away. This happens on MR1 and MR5.