I tried to listen to hd800 amped from everything, and starting from fiio e12, and amp by amp moving to matrix m-stage hpa 2, Burson soloist sl, woo audio wa3, woo audio wa6, m2tech marley, woo audio wa7 fireflies, woo audio wa6-se, sennheiser hdvd800.
It was getting real late when i got to hdvd800, and i fel very very little difference between amps. To be true i could barley difference e12 and hdvd800 on hd800. I mean, both are neutral, work great with hd800, and at the same volume there was virtually no difference. too minor for the price. The volume was a problem though.
Amps with lamps sounded different, but i am not really into that sound. Lamps were what the amps ship with. They were not neutral, and did not change hd800 in a good way.