You are probably correct.I don't want to start a big argument here, but I believe that J The Killer has stated he has difficulty hearing any difference. Might I posit that if he is only playing the file from a Thinkpad W530 with an inexpensive Realtek audio chip with no other DAC or amplification involved that we need to look no further for an explanation?!?!
Back to topic: I still prefer the HD650 for vinyl. Keep in mind almost 100% of my vinyl is metal of some kind. The HD650 just handles crappy, old, and grainy recordings better which is the vast majority of the music I enjoy for some reason. Heavy distortion on the HD650 is just unbeatable, and I am glad it gives me a reason to keep the HD650. For every other genre, and especially movies, the 58X is simply excellent. Anything with a deep bass and well produced is just superior on the HD58x in comparison.