I'd like to share my experience with amping the DT 770. I have the 32 ohm premium version, which are said to be fine for mp3 players and laptops. I used them for a few years, but I was never really impressed with them. They sounded better than my previous headphones but not enough to blow me away. Recently I decided to buy the Schiit Magni + Modi combo to see how the sound improves with these cans, as I've read that the Beyerdynamics are quite power hungry at all impedance levels. What I've found is that they are much more pleasant to listen to with the amp. There is so much more impact - it's like I can feel the power of the current driving the headphones with each bass kick. Before, the bass was there, but not really noticeable and sounded weak, like an afterthought. The highs really scream, which can be grating on poorly mastered tracks but sound beautiful and euphoric on a great track. And they just sound better and better the louder you turn them up. With my laptop or soundcard if I start turn to turn it up it's the same sound, just louder and more fatiguing.
With the amp it's like I can hear every detail even better and a whole new world opens up, not fatiguing at all even on very high volumes. It's like before I could only access a compressed version of what I'm listening; now I can hear the full range. When you do A/B testing the difference isn't massive, but sitting down to listen for a long time the amp makes a clear difference. It could also be the DAC that's making the difference - I wish I had a way of testing this as I have no other amp.
Edited by BrianPeppers - 11/29/13 at 3:00pm