I would also suggest adding into the mix the Lehmann Audio Linear SE. I was fooling around with the gain settings on the amp, and going to the 0db to 10db setting made the hd800 jump to life. It was simply stunning. Prior to this I was primarily using a Lyr with the 800, which sounded great, but the Lehman has really opened everything up. Improved dynamics, greater clarity without any added glare or hardening of the treble, and an iron grip on the bass. The 800 sounds very musical with this pairing without accenting any negatives.
Fascinating. I am currently plugged into Oppo103 - Kimber D60 coax - Schiit Gungnir - Kimber Silver Streak interconnect - Lovely Cube amp - HD800 with stock cable. The power cables are Kimber PowerKord 300 throughout and the combination is magical. The Schiit Lyr, which I bought as an upgrade to the Lovely Cube (and on which I spent $$$ in tubes), is not as good with the HD800 as the Lovely Cube Lehmann clone. The Lovely Cube really is stunning. You can imagine how much I want to audition the Linear SE!