Unbelievably good SQ mystery, needs solving!

hello everyone, 

sorry if this might have been discussed before, but i tried searching and found not much.

about 2 months ago, i went to an earphone shop to try some IEMs, and i tried the se530s. the seller let me use his sony CD walkman to try the IEMs. it looked a bit old, like ends of the 90s, maybe around 2000.

i was immediately blown away by the SQ. at first i thought it was the se530, with all the praise they got here and all. but then i tried them with my source (Zune HD), and the SQ was, although good, i wasn't blown away like with the walkman.

and since then i've trying to find that amazing SQ. i've tried lossless, amps, AT CK10s, Westone W3s and some other IEMs/earphones. never got that "blown away" effect aver again. and it's driving me crazy! xD cause i know something drastically better exists and i WANT! i've even got a strong urge to save up for the JH13s. 

it's obviously the source files and the source, so i'm asking what other source could get a comparable SQ? 

thanks for your help!

thanks. 

could it be 24 bit lossless that made the difference?

what bothers me the most actually, is people keep saying these IEMs or this source is really good.. but you never really know how good compared to something else, so i couldn't figure out what the step up in SQ would be equal to.