I've just got back from a three mile morning walk with two dogs, an SGN3/E18 & HD650's. We live in the sticks, literally no-one for miles. The E18 does a fair job of driving these headphones. Volume @ 7, low gain, bass boost - if ya' feel lucky - on. I think I'm really beginning to appreciate how fast these are, they're rhythmic & timing abilities are frankly awesome to my ears.
I only have two negatives...
1. I'd be incredibly self-conscious wearing them in public as portables.
2. I can also hear Emmerdale.