Originally Posted by jasonb
The 550 is said to sound pretty much the same, but yes the 550 is also said to be easier to drive.
The Q701 can be driven just fine from a Fiio E10, E11, or E17 though, so it doesn't cost a fortune to use them properly. I'm very happy with mine used with an E17.
I wouldn't risk it...Many people said that they are even harder to drive than HD600/650
I want my headphones to sound perfect to what they are capable of (or at least 90%), not just sound fine. My budget isn't huge so I try to avoid amp-picky cans as much as possible