if you really what to ooze clarity out of the Heir 4.Ai and do not want to spend a lot then i do not think you can go wrong with the hippo cricri which is a lovely tiny amp and just adds a bit more high mids and really does great things for clarity! Its also really cheap, Jaben sell it!
My review is here:
It seems like a great amp, thanks for the recommendation. Do you think it has more battery life than the fiio e11? Only bad side is I can't use it with my iphone.
Edited by daniel521 - 1/30/13 at 7:26am