Ok, just got done with about an hour and half listening session with the LCD-X (Wywires Red cable upgrade) and HD-800 (Stock Cable).

This unit really is quite the swiss army knife with all the capabilities it has.  However there are caveats.

1)  This is a fantastic unit when used as a pure DAC using the fixed outputs into a preamp.  I hooked it up into an EAR 868 preamp which feeds two Concert Fidelity ZL-120V2SE monoblocks feeding a pair of Marten Design Bird 2 speakers.  Glorious sound...rich mids, a fully extended but full sounding top end and a nice round bass performance.  Now, there is a somewhat different presentation of what the Marantz unit likes to present as "Air".  This "Air" that should have the top end shimmering feels somewhat recessed.  Akin to a warm sounding tube unit...the details are there, just with a fuller warmer presentation.  I like it as there is top end WITHOUT etch.  A Marantz hallmark of sorts.

2) The unit becomes very mediocre when used as a preamp through the variable outputs into the Concert Fidelity monoblocks I am using.  The sound becomes 2 dimensional with very little soundstage.  There is a heavy lack of depth in the performance and the sound just becomes kind of dull.  Almost felt like a blanket was thrown over the whole system.  The sound is more for background listening rather than worth your limited, dedicated, all attentive listening time.  Just don't expect much in this regard.

3) Now for the sound of the Headphone Amp with the Audeze LCD-X.

The presentation of the unit changes quite a bit depending on the gain you set the amp at.  LOW, MID or High.  I found that for a most cohesive, well laid out sound, the "Mid" settings seemed best.  The LOW setting just didn't have the oomph or power in the low end to provide the music a basis or foundation to build upon.  Decent rendering of the midrange but the high end seemed to stick out more in the mix.  I guess, there might be some headphone where this kind of presentation works, but didn't work with the LCD-X at all.

The MID setting provided the most even top to bottom presentation where the house Marantz sound showed best.  Almost like the unit was tweaked to sound best here.  A full sounding and controlled bottom end here.  The midrange was again full and rather intimate sounding.  Nice fully developed tone here to voices, drum skins and instrument rendering.  Top end is superbly balanced though I wish I had more "air" around cymbal work and shimmer.  I guess this is more about the sound of the LCD-X.  The HD-800 had STUNNING top end that is well extended and full when needed. 

The HIGH setting is powerful, but the noise floor is definitely increased with the LCD-X.  The background isn't as black from where the music emerges.  Also, I felt the sound got congested where the soundstage became even more squished.  You get your loudness, but the mix really gets thick sounding as well.  As if the room became much smaller.

If you guys have specific questions, I can try and answer them.  The unit is going back to my buddy on Sunday, so I only have tonight and tomorrow sometime to play with this unit.

BUILD QUALITY is fantastic for this price.  The unit is solid, sturdy and oozes class.  Typically never seen at this price point.
I like it this unit and just have never seen such performance at this kind of price point.  I will keep my eyes out from now on for such high bang for the buck sound.