I was wondering about the amping with the HD800. I bought a 50wpc amp for the HE6 but was wondering about if it was safe to try it with the HD800 to connect it straight to the amplifier. Volume won't be an issue since there's a knob and I also have a preamp but wondering if I needed anything like the HE adapter from speakers to 4 pin XLR?
In my opinion -- and it's just that, my opinion -- the HD800 are not difficult enough to drive to make me consider plugging them directly into a 50wpc amp. The HD800 sound excellent with good-but-not-overly-powerful amps like the one found in the Grace m903, while the HE-6 take much more grunt to get the job done.
The risk/reward continuum is therefore much closer to the "risk" side for me with the HD800. Your calculus might be different.