I beg to differ a bit with Nebby. I tried the combo when I received the PP and while "powerful enough" the sound to me ears was more in the cold and sterile side of things than when using the Luxman P-1 or the Gilmore Reference. Still a listenable combination. I didn't try both using a premium source though, just the iTouch with a LOD playing ALAC files, so this comment should be taken with a grain of salt, specially if Nebby used a high quality source.
My intention was just to assess if the PP-HD800 could be a good portable system, so the source had to be the iTouch.