guys sorry for replying to this old thread :D but i think ive found a solution to remove the hiss in the speaker without loosing its not much noticeable anc and without loosing the build in amp :D xD
i was tired of my executives with this his so i startet to look for the chips and so on i found the main chip with the amp and anc build in and i found the datasheet for it :D after long searching i found 2 points behind the anc and before the 2 contact points come from the output on the circuit to the speaker that dont have this brain****in hiss :D.
this two points are the + for right and one for left speaker :D
maybe some one with some time and a executive laying around want to test this too :D
here is a picture
NOTE: NOT the left point on the lower side of the picture ! the right one marked on the picture is the one that delivers the right channel !
pls let me know if u can hear some difference in sound quality after this mod :D i dont hear a difference only the quietness when i hear on lower volume or without any sound :D because this hiss is gone
I am not responsible for any damage you do to yourself or your headphones ! this will void your guarantee ! do it at your own risk !