I currently have a EHHA amp built by dBel, and I love it. But I worry that if something ever went wrong with it I'd have no clue how to fix it, and would have to go back to Donald with hat in hand.
Maybe I should just be happy with what I have, but I'd like to know that I am getting the most out of the Denons. I actually think they a nice sounding headphones. Not near as good as my HP1s, but damn comfortable and better than average sounding.
I'm considereing the ZD. That amp is highly regarded, and should sound good with my HP1s and the D7000s.