Have been using the AKG K240MkII for a while but I have recently purchased a pair of AKG K702 headphones........... first impression, even before burning in, they are awesome.............. I am currently using the headphone output of my Marantz PM 66SE.... which is pretty good.......... but this...

Hi, at low volume levels the phones are fine but as the volume increases on tracks with some deep bass, there's a very noticable rattling coming from the right driver of my K6s,   I have noticed that if I wind the volume up............. past the point where it's comfortable to listen to...