It's finally easy to be impressed by HD800 the first time but It's a bit harder to live with it week after week . It definitely needs a well choosen upstream gear . Not necessrarily expensive gear but well choosen. I purchased a HEGEL HD10 DAC a month ago. Very good DAC, neutral , accurate , not too analytical but .. HD800 hates this dac and Music enjoyement became a nightmare . I've a loaned Rega DAC right now and pleasure is back. Subtle differences indeed but these subtle differences can transform dream into nightmare with HD800.
The HD800 is really a very special thing. OK I admit I beat a dead horse but now I can talk about my own experience.
I had a similar feeling when I got my Buffalo III. Of course I eventually replaced the HD800 with Stax but nonetheless the HD800 is a picky little thing. If not for the Buffalo there's a chance I might have sold the HD800 instead of the HE6 when I had both.