HD580 do not. I used several amps with them and they sounded identical coming out of my PC or ipod. I venture to guess the 600/650 are not much different. Most of head-fi is bogus, don't believe all the reviews. Alot of it is not about good sound, its about subjective infinitesimal differences that these guys use as an excuse for an expensive hobby. Sources are so good these days, spend your money on headphones. Maybe the 650 does benefit a little, but i remain skeptical with all the bs i have read on these forums. The hd580/600/650 is one of the best headphone platforms around. Infinity comfortable with neutral clear sound.
If you dont believe me, ask yourself about the cable crowd. 200 dollar headphone cable... lol wow
Edited by Crazy*Carl - 9/21/11 at 2:24pm