AI want to clarify something - I am NOT saying that any old speaker amp will drive the HE-6 better than a really good headphone amp. It's probably not that simple. I found that the Leben sounds better with the HE-6 via the speaker taps than the headphone out. But the Leben is a really killer speaker amp, not any old run of the mill jobbie. I have not tried a cheap stereo speaker amp. Not sure whether that would sound better than something like the Woo WA2 or not. I don't have a suitable cheap speaker amp to try it with.
I hope no one would even consider putting a crapy speaker amp on these. A crapy speaker amp is the same as a crapy headphone amp; they are both crap. The point myself and others were trying to make is you don't need to spend a small fortune on a speaker amp that will be a good match. I think it would cost far less to drive them to their potential than it would cost to drive the hd800s to their full potential.