i feel the same way with the HD 800 and the right tubes on the WA6-SE, when its not well driven, its liquidity becomes muddy, smearing details while having a hotness in the treble. the soundstage may seem artificial and forced, and its presentation lifeless in nature.
with the right tubes, i agree, the headphones just disappear, the music is all around you, as if it was just coming out of thin air, and its liquidity is something that i begin to appreciate more and more, the music just blends so perfectly together, its something quite unique to the HD 800, i haven't heard another headphone that does it so perfectly. its not super detailed or fast like a T1, or warm and full like an Audeze, its just the liquid decay which adds an extra texture to the music.
+1 to your plus 1
Ever since I upgraded to the Cary SLI 80 and retubed and biased it properly, even with the Lyr standing in on DAC duty I simply can't stop listening or daydreaming about listening when I get home. Putting on the HD800s, turning on a mild crossfeed and firing up some Hesperion XXI has been my go to stress relief after work. All the technology just evaporates and if I close my eyes I'm in an audience hearing troubadours play in a French castle 700 years ago.