|Originally posted by Music Fanatic
Well, I must disagree vehemently with this. From an electrical engineering perspective, since the signal is transmitted digitally, replacement of the optical cable will only provide psychological improvements, not actually measurable improvements. Since the signal is digital, as long as the optical cable is functioning, it will function at maximum performance. I'd go with the cheapest possible digital cable. Since the included cable is free, that would seem to be the cheapest.
As far as clipping is concerned, check the power on your portable headphones. Are you sure they are really fully charged? Weak power can definitely lead to noticable distortion. This is mentioned prominently in the manual (unfortunately, in Japanese.) Otherwise, unless the source material contains distortions, the headphone shouldn't distort.