Just plugged mine in for the first time. Very closed off right now, so they're burning in in the other room. I hope they get substantially better! Using with an AudioGD R11. After ordering I got some other headphones in the meantime, Audio Technica A990Z. Build quality on the AT is better by far, I'm hoping the sound of the 6XX ends up surpassing them (it's not close out of the box). The ATs also cost me half as much! I got a great deal, I think they are about on par for cost normally. These two sets are my only experience with audiophile headphones.