I'll keep this short.  I used this DAC with my Thunderpants orthos, and a Cavalli CTH amp, hooked to my WIN7 64 bit computer.  The sound was pristine.  I had upgraded from another Dac - Keces 151 MKII (about $300) and the sound quality increase was more noticable than i thought it would be.
 
I dont have lots experience with dacs, but this DAC just sounded really great.  having the option to go true solid state, or true tube output at the touch of a button was really nice.  I left the tube on at all times.  it simply sounded noticably  better - fuller and richer.
 
I dont feel this dac colored the sound, it simply allowed more of the richness and purity to come through.. thats the best way i can describe it.  I would liken it to buying a better pair of headphones.. the sound was simply more true to life than before. 
 
I would be willing to bet that one would have to spend thousands to outdo this sound, and the diminishing returns would probably be a big factor. 
 
construction, looks, and build quality are all better than average on this Dac.  all the pieces, casing, knobs, buttons, feel really solid, and accurately fitted together.. like a BMW..  it just feels like a very precisely build piece of professional equipment.  I also really like the finish on the metal.. you can barely see it in this photo, and i dont know what its called, but it looks really sharp.  Its like if metal had a wood grain..
 
you cant see them, but the dac also has some very fine aluminum and rubber feet. a nice touch.
 
I would agree with the glowing review that 6moons gave this dac.  Its a winner!

As I always say, I am an ameteur reviewer, so please keep this in mind. 
 
I should just state out front that I think these are pretty great headphones.  In the simplest of terms, they just sound good.  Relative to their price level, I believe that Liking vs Not liking these headphones is simply matter of personal taste based on the type of sound you like.

equipment used to test: win7 64bit Foobar/wasapi  Keces DA 151 MKII dac.  Hifiman EF-5 SS/Tube hybrid amp, Decware Zen Head Solid State amp.  Radio shack cables.  ears x2

put over 200 hours music burn in on these and have owned them roughly 1 month.

Build/Comfort/fit - 10/10 very sturdy, and very comfortable. not too tight, not too loose. Very light.  Exceptional Quality all around. It really doesnt get much better than this.  I am able to wear these cans for hours with no discomfort
I also really like the cord.  It feels very sturdy and yet is very loose and flexible and just stays out of your way.  The wood enclosure around the end plug is a nice touch.  Compared to the d2000 cord which while it was very sturdy was to stiff and unruly.
I feel like i could drop these from a pretty high distance without hurting them... lets never find out.
Obviously these are exceptionally beautiful cans

Bass - 9/10 A good amount. less than d2000 but not a lot less.  the d2000 excelled in its frequency response below 50hz, but w100x is definately cleaner, more refined, more precise and punchier.  As described: tight, precise, punchy, fast, but they dont extend low enough for my taste.  I noticed this as soon as i tried them, and it bothered me. using a sine generator i can hear them roll off very sharply right under 50 hz which confirms what i was hearing. sounded much better on the zen head than ef5

Mids - 7.5/10- Also very precise, fast and clean, but  forward and sibilant but othwerwise great! this seems to be a common feeling among other owners, and again,something that struck me right away.  the mids are in your face compared to my old Denon d2000 (though in all fairness the d2000 seem to be known for pretty laid back mids) there is a sibilance around 4800hz that just hurts a little without an eq. I use a parametric EQ on my PC to pull it out and then the issue is gone.  I hear sibilance prominently in men's and especially woman's vocals This improved switching to the EF-5 over the zen head, but still bothersome without an eq. I am biased b/c i dont like forward mids , but the sibilance really gets me, and a few other owners have told me the same. That aside - the mids are pretty darn good. With other equimpent, the sibilance may not be an issue.. i dont know, but it certainly seems like some hear it more than others for whatever reason. 

Highs - 8/10- again tight, precise, and fast and clean. not so much on the hybrid as the solid state
though..  again,  Much better sounding on the Zen Head than the EF-5

Soundstage - 9/10 - pretty darn good.  because of the forward mids things feel a little closer in, but
at the same time the overall stage feels big to me. I got a great sense of feeling like i could pick out where in the room the musicians were, and the seperation and detail is really excellent.
These headphones are not forgiving.  You're gonna hear everything in the recording for better or worse

Overall - 8.5/10

In their price range these are very competitive headphones. If they suited my personal taste i would
definitely say they are keepers. I think these headphones would suit people who listen to rock, hip hop, techno, Metal and maybe classical.. and not so much people like me who listen to jazz, female vocalists, acoustic, folky, etc...but again i guess its really more about your preference in how you like your headphones to sound. They are not for me so please forgive me for being slightly biased in that regard.  They are potentially - with the right amp -  very precise, tight, punchy, wide sound stage, seperated, and fast headphones.  I should note that most of these words were not in my audio vocabulary until i tried these cans and found them to be all of these things compared to my denon d2000's - and I really liked my d2000's.  Instrument separation and the "noticing things i never heard before factor" is really nice. definately a plus.

If anything i think I found these cans a tad clinical - as in they didnt feel as musical and smooth
as i would like them to. I guess its because i compared them to the lush, laid back sound of the denons.  I have to admit, going from one end to the other in these 2 headphones took some serious getting used to.

A few extra notes:

these cans just dont sound right with my hifiman ef5. i dont know why.. maybe its a power mismatch,
but with the decware everything was crystal clear, seperated, clean, pricise, punchy etc..
with the hifiman ef5 much of that was lost.  low mids and bass got muddy enough to actually be
annoying, highs rolled off a bit and lost their edge, and overall everything just lost its shine. I tried 2 different tubes and a transistor (tube replacer)  Maybe they are just finiky.. i dont have enough amps to test that theory. 
 
I always eq my headphones as close to flat as possible, and though i do eq these a bit, i actually found them to sound best with very minimal eq - mainly removing the sibilance.  Otherwise they actually sound quite balanced. always a plus. 




 

I have owned these cans for a few months I am reviewing them in the context of them being a 200-300 can.  so im not comparing them to HD800's or Beyer T1 b/c they are not in that league and are not expected to be.
 
I am an ametuer reviewer, so please keep that in mind
 
I should be clear when i say  actually like these cans, because much of my review may sound to the contrary
 
In brief - these cans are laid back and smoothe. quite imbalanced without an EQ but capable of great things with a little patience and an EQ
 
In fact i will say that for the money these are some of the better cans you can get  Sure there are lots of other cans in the $200-$300 price range that sound just as good, but at that point it comes down to preference, and we'll visit that later
 
The major issue with these cans is that they require an eq.  Without one, i am not exaggerating when i say they are hard to listen to.
 
I play a sine wave through all my headphones to find where they are imbalanced and eq appropriately.  These took some serious work to flatten, but it was worth it!
 
they have huge frequency imbalances , which seems to be a universal experience with these cans.
 
Here is how I have to eq these cans to get them to sound "flat" across all frequencies

 
Imagine all those valleys as peaks, and vice versa, and you can see how they would scream in your ears without an eq
 
The reason i am so fond of these cans is that they are CAPABLE of sounding great.
 
Thats really what seperates average phones from audiophile quality.  Sure each phone has its peaks and valleys, but the best ones are capable of handling much more than their stock sound whereas cheap cans or buds simply cant produce no matter what you throw at them
 
So for the sake of the rest of the review, lets assume we have properly flattened the sound.
since you will probably use them at home anyway.
 
 
BASS: 8.5/10 bass to me is almost purely a preference game.  No two people like their bass the same, and no two will call a "flatly" eq'd sound the same when it comes to how the bass "should" sound.
 
these cans are commonly known for their more than ample bass.  it should be made clear though, that quantity and quality are two different categories.  in this case, these cans have some of both.  though the bass is not totally clean, as it does get  slightly muddy at times, the bottom line for me is this -   Yes these cans have a bit more bass than some people prefer, but the great thing is you can simply eq some of it out and you lose nothing.  The sound quality only improves. and for those, like myself who occasionally like to rattle their eyes, its there when you need it.   The frequency extension is really good.  i can hear 20hz on the hi-fi heartbeat track no problem.  I have tried other cans that didnt have ample volume at frequencies below 50hz like these have, and i missed it sorely.
 
Mids 9/10 - I feel the mids on these cans is about laid back, and im pretty sure most people agree.  This means that the mids are sort of in the background compared to the rest of the frequencies. I like this though and i feel they just sound great, no matter what i throw at them.  I especially like how they sound with jazzy, vocal, or acoustic tracks. 
 
Highs 9/10
Again, when eq'd properly, do very well.  Everything is in its place and nothing gets mushy or tinny.
However, without an eq.. well... ouch! 
 
Soundstage: 9/10  this one is tough for me to describe.  I remeber upgrading from some sennheiser hd555's and being blown at the difference in how expanded and immersed i felt with the D2000 in comparison.  thats the best i can do
 
Build...10/10 this one is easy.. these things are SOLID.  Very well built from cup to headband cord and everything in between.  The cord is a bit unruly though.  While i do believe it could stop a bullet it is too stiff. 
 
Comfort: 10/10 another easy one, very comfy.  i often forget to take them off and wear them for hours with absolutely no discomfort.... really.
 
Fit: 8/10 they dont fit very tight, again this seems to be a universal sentiment, but for me this did not cause an issue except that they offer very little isolation.   If isolation is important, these cans are not for you.  I should also note that i have a small head.
 
Overall Sound: 10/10 I feel these cans have a way of adapting to my musical needs.  I listen to a very wide range of music from metal to jazz to acoustic to hip hop with pounding bass, to classical to eastern, to meditation music.   I dont feel they really fall short in any category, though they do better with smoothe laid back music than they do with hard precise or powerful music. They are just a great all around listening experience in their class.
 
Portability.  none. Not meant for portability.   These cans are not a good option for portability.  The cord is too long and too thick, they dont isolate, they are pretty bulky and if you turn your head too fast they will probably fall off.
 
I would highly recommend these cans for someone who is just stepping into their audiophile shoes, and beyond.    If you are willing to put in a little work and break out the EQ you will be very happy
 
to summarize again.  a pretty capable laid back smoothe sounding headphone with ample bass, nice sound stage, and a generally Fun and Forgiving sound signature.  Use and EQ and you wont be dissapointed. 
 
If you are anti EQ however, i just cant recommend these cans - they will not be a pleasant experience
 
without an eq i could not listen to these cans for more than 10 minutes.. it just hurt..  with a flat eq, i felt like i could keep them on forever...

short and to the point
 
I did not like how these buds sounded or performed
 
they were unable to produce frequencies below approx 100hz and rolled off substantially above about 2000hz
from 100-2000 they were quite flat though
 
i confirmed this using a sine wave and a parametric eq to test the flatness of their sound
 
no amount of eq could fix the bass, since they seemed incapable of producing it
 
mids were pretty good, as were highs if you generously bumped them up with an eq
 
sound stage, mids and highs were all above average (average being cheap ear buds) if properly eq'd, yet the lack of bass made them sound empty
 
amping these did not make a difference
i tried burning in (only about 10 hours) also no difference.  (i am neither a firm believer, nor disbeliever in burn in, i have simply never put any focus on trying it)
 
these buds seem durable, and fit well as buds
 
as iem's using various attachments - un-usable.  couldn't get a fit at all (seems to be a unanimous sentiment from all owners of the OK series)
 
I would not recommend these to anyone unless you don't care about bass at all and can eq them properly.  they are overpriced for what they deliver.