I picked this up last year here, and have discovered that my headphone listening is either on the go, or via my setup in the living room, so the portability of this unit does me little good and it is just sitting.
Have a read of the reviews, I could not describe it better. Suffice to say that it is a great unit, suitable for different phones, and is portable - note I saw portable vs truly for use on the go.
It works perfectly, and will likely last a long time, it is a brick!
http://www.decware.com/newsite/zenhead.htmhttp://www.decware.com/newsite/zreview133.htmhttp://www.tonepublications.com/review/decware-zen-head-headphone-amplifier-and-phiaton-ms400-headphones-2/Currently sells for $429.
I will let this one go for
US$200, now US$170 US$145 shipped anywhere in North America.I would also straight up trade for Senn HD598, AKG 7XX, AKG Q701, AKG 702 or other over ear open back headphones.