I'll still have to compare mine to my brother in laws pair, which have been used for +1000h well I'd be interested in what you learn from that but that would also depend on what music he was playing through them the quality of the tracks how much he has actually worked the drivers if he is also using a bass boost and a $500 amp like you right ? If he's been using them off an iphone they would curtainly sound different to your pair there are to many factors I guess but still interesting
I gave the S500's to him coupled with a Fiio E07k as a birthday gift and he's been running them together ever since! I myself have always used my S500's with a E17 (sometimes docked to a E09k), so the influence of the amp should not be a big issue. We listen to roughly the same kind of music too.
Damn discussion this has spun OT ES700 ES700 ES700