This is one of the few amps that pairs extremely well with both the Audeze and HD800 signatures. However, the ZD with the X is sensational - a very musical and emotional pairing. I typically hear my 2.2 or his 3 on my friend's unit, but the X is my favorite pairing from the family, a new addition of his. Just heard the new ZD paired with my 2.2 and it from memory seems to be a step up again.
Really agree with you. I noticed that the LCD-X pairs very well with OTLs.
I would also pinpoint the new ortho from Kennerton, the Odin. Less dull, bass impacted.