I don't know what your budget is and I'm not familiar with the amps you've listed, but I would look at one of these:
http://www.meier-audio.homepage.t-online.de/index.htm
The Eartube to be exact. I have an HA2-SE and I'm very happy with it. Dr. Meier is very easy to deal with. Go to www.headfi.org for more opinions.