You can replicate a straight-forward sound signature, but this won't recreate the overall sound of a player as so much more comes into effect. Whether it's a degree of "good" distortion the player introduces (i.e. like tube amplifiers add distortion which many find favourable), a specific timbre to the sound, detail retrieval, or some other subtlety in exactly how the analog signal is formed via the DAC and amp built into the DAP.
I honestly don't believe I can make my Cowon X7 or Rockboxed iPod 5.5G ever match a DX100's or HM601's overall sound. Signature? Yes. Total presentation? No.
(That said, I'll gladly be proved wrong)
..Of course, you won't be proven when "testing" yourself - the power of the placebo effect, especially on people who are self selected for higher than average suggestibility, is pretty damn fierce. But could someone fake you out in a blind test? I'd be amazed otherwise. Because that's what a history of thousands of similar tests say.
Edited by scuttle - 2/18/13 at 11:35am