Drake Mallard

HD 569 sounds like crap. Better alternatives if you want closed headphones:
Status Audio CB-1
M40x with replacement pads
Superlux 681Evo with replacement pads

Here you go. Headphones that people can't see

At this point I think most people in the tech world and audiophile world have heard of the crowd buy site Massdrop. They have quickly become known for their low prices, amazing exclusive products, long wait times, and a few sketchy things in the past. One of the thing they have become widely known for is their exclusive collaboration headphones. Massdrop works with companies to make a rebrand or a completely new headphone based off a more expensive existing headphone and sells them for less. They have become popular quick, and they sell a lot of headphones, Most popular are the under $200 headphones, and I see a lot of people asking which one to get. I already owned the HD6XX, so I decided to pick up what I think are the other big three under $200, the AKG K7XX, the Fostex T-X0, and the Hifiman HE-4XX, and put them through an audiophile shootout to let you all know which one to buy. I hope you enjoy.

Sennheiser HD6XX $199:

(I copied this from my HD6XX vs T50RP review so @GamerDude I'm sorry again for the tag)
These are a headphone that probably need no introduction. These headphones came to be back in 2016 when Massdrop collaborated with Sennheiser to make the legendary $500 HD650s be able to be sold for $200. Many people question the build and sound quality becasue it seems too good to be true, but there are only a few differences. 1. They are midnight blue instead of gunmetal grey like the HD650s. 2. They have a matte finish unlike the glossy on the HD650s. 3. They have a 6ft cable that terminates in a 3.5mm instead of a 10ft cable that terminates in a 1/4in on the 650s. That's it, there is nothing else that is different with these from the HD650s.
 
Build:
These are one of the most legendary headphones of all time, they are built well. In classic Sennheiser fair all the materials used feel nice and high quality, lending to why there are still many pairs of HD650s from 2003 still kicking around. The plastics feel high quality and there is a nice feeling piece of what I assume is spring steel making up the headband. Just like the 650s these can easily be fully disassembled and modified. The pads are very large, what I would call a 4 finger pad (meaning you can put 4 fingers of a fist in the hole of the pad), and the head cushioning is very supple and soft. The entire package just feels very well built and solid. Not any foldablity so not good for portable use. Of note after I bent the metal to reduce the clamp I got some squeaking that I fixed with some silicone grease. (Build: 8/10)
 
Comfort:
These are among the more comfortable headphones I've ever worn, once you fix the major problem. The HD6XXs like the HD650s are known for a stupidly strong clamp force. I can tell you right out of the box these clamp like crazy. It's almost to the point where it hurts and it feels like it's cutting off blood flow to your face. On the upside these will never fall off your head. For any of you who are Air Force fighter pilots and want to replace your standard headset with a pair of HD6XXs, go right ahead they will not fall off your head no matter what kind of maneuvers you do. In order to fix this clamp force you have to open the headband up all the way and bend the metal and it massively reduces the clamp to the point where they are very comfortable. Don't get me wrong they still have a strong clamp, but they are actually very comfortable now, and they still won't fall off. Plus with the combination of the large velour pads, and soft head cushion, these are a headphone that I have no problem wearing for long hours. Also of note these are pretty deep so you won't have to worry about your ear hitting the drivers which is always a huge plus. (Comfort: 8/10)
 
Misc, Wires, Power. and Accessories:
As for other thoughts, the stock cable these come with is ok. It's a 6ft cable that terminates in a 3.5mm jack (with a 1/4in adapter included), and it works. I could live with it if I had too, but of note I replaced that with a 7ft balanced cable from Periapt Interconnects. I do think that balanced makes a considerable improvement to the sound quality, but to make it fair I am going to compare the two using the stock cable. Also the 6XXs come in a super nice hinged box with a nice foam insert that holds them nicely. As for how hard they are to drive, they aren't that hard. People freak out with these because they are 300ohm, but honestly they don't require a ton of power. Your phone will push them, not to their full potential, but it will push them. Not that you'd probably want to use them with your phone because these are open back headphones and they leak sound like crazy. Everyone around you can hear exactly what you are listening to. Also note these are made in Ireland, while the others are Chinese made.
 
Overall sound:
Overall if I had to describe the sound of these headphones with one word it would be "Pleasing". These headphones are just relaxing. They never hurt and they never get tiring to listen to. Some headphones like the M50Xs are what I call, "Over ear IEMs" they are so intense they sound like IEMs because they sound like they force the sound right down your ear. These never do that. These sound like they just place the sound in the cups and you just hear it. It is hard to describe but I can say it's a wonderful experience. Are these HD800Ss? No. But these don't sound like $200 headphones, these can easily throw punches with headphones 5x the price. I think @GamerDude put it well when he said that despite his collection of headphones ranging from $100-$3000+ these can trade blows even with headphones like the $3000 HE-1000s. Are these as good at the HE-1000s? No, but it's pretty scary how well these can play with the big dogs.
 
Mid Range:
The 650s/6XXs are known as a "Veiled" headphone. That means the vocals tend to be recessed. While I would say that is true to a degree, most of that criticism comes from the original design of the HD650s which was later changed in order to combat that veil a bit. The vocals are a bit recessed compared to other headphones I've heard, but they are still spectacular. They are super crisp and clear and never get lost despite them being slightly recessed. These headphones do vocals well for those of you who like music that is vocal centric . (Mid Range: 7/10)
 
Treble:
Treble I find a hard thing to rate because in my mind it's subjective. Some people like a lot of treble and others don't. I think there are two parts to this category, amount of treble and quality of treble. As for the amount, these are not treble heavy headphones which is why they are so easy to listen to for a long time. However that doesn't mean the treble is bad. The treble is very smooth and relaxing. There is this crispness and sparkle to the treble that is simply amazing These headphones excel at classic music. If you are one of those people who likes to kick back and relax listening to classic music these are the headphone for you. (Treble Amount: 5/10) (Treble Quality: 8/10)
 
Bass:
This is the one category where the 6XXs do not shine. These are not bassy headphones, there's nothing else you can say. Now they do have bass, these are not HD600s where the bass barely exists, but for bass heads these are not what you are going to want. In fact I actually dislike listening to bassy hip hop or rap music with these. Could I listen to deadmau5 with these? Yes, but they wouldn't be my first pick for EDM. Now the bass itself is very tight and focused, and it has what I would describe as a booming sound, even though there isn't much of it. This is hurts their gaming performance a lot which I will get to later. They don't have bad bass just not much (Bass Amount: 5/10) (Bass Quality: 7/10)
 
Sound stage:
These headphones have sound stage, but not a ton. Are they wider than M50Xs? Yes. Are they Fidelio X1/X2 wide? Not even close. Personally not having a super wide sound stage doesn't bother me, I just need some. (Sound stage: 5/10)
 
Imaging:
As for imaging these are very good. I remember one of the first songs I listened to with these there was someone playing a piano and I remember flipping out when I could hear the difference from left to right of the guy moving up and down the piano. These image very well. (Imaging: 7/10)
 
Gaming:
You won't realize how much you dislike these for gaming until you try something better. I actually enjoyed these more for gaming than my M50Xs. I enjoyed these a lot in games due to their spectacular imaging and decent sound stage. But spoiler alert, once I got my T50s I realized how much I disliked these in games. The one big problem they have for gaming is that light bass. It makes gunshots in FPS games sound anemic. There is no life to them, you hear them but don't feel them. On headphones with more low end you can actually feel the gun shots, the 6XXs you can't. Imagine firing a real gun and hearing the sound, but there is no shock wave, it's like that. If you don't care about that or don't play a ton of FPS these do very well for gaming. And I will say I do like their sound stage over the T50s for games, but I just can't get over the light bass as someone who plays almost entirely FPS.  (Gaming 5/10)
 
AKG K7XX $199:

The AKG K7XX is the first ever Massrop collaboration headphone. They are a cheaper, Chinese made version of the K702 anniversary edition, at least that's what Massdrop claims. I haven't heard the K702 Anniversary, so I can't speak as to whether or not this is true, but what I will say is if the K7XX and K702 Anniversary sound the same, then the K702 Anniversary is extremely overpriced at $430. (Also please excuse the plastic I left on over the glossy plastic in the pic)
 
Build:
These headphones are not built that great. They are entirely plastic, and somewhat cheap feeling. They have that plastic China made rattle and creaks that you expect, unlike an Austrian made set of AKGs. The weakest link definitely seems to be the headband and the plastic arches that make it up and houses the bridge wires. I have seen a lot of people break these, and I can see why. The headband is the standard AKG gravity adjust system, with a fake leather strap which actually feels pretty good. This wouldn't be a set of headphones that you would want to drop on a hard surface, they would probably break. (Build: 4/10)
 
Comfort:
These headphones come so close to being very comfortable, but fall short. They are very light and I actually like the gravity adjust system. Even though there is no padding on the headband, they feel very comfortable. Where they fall short is the pads. These have the AKG memory foam Anniversary pads. I know some people who love these pads, I get why, but I hate them. While they are massive and round, anyone's ear would float in them, they are too thin. My ears hit the inside of the drivers, which really hurts after a short while making them uncomfortable. If you have a set I highly recommend picking up the Dekoni Velour pads which are thicker. I briefly tried these with the very thick Brianwavz XL pleather pads, and they become very comfortable, but with the stock pads, they just aren't that great. (Comfort: 5/10)
 
Misc, Power, Wires, and Accessories:
As for power, people extremely underestimate how hard these are to drive. Tons of people runs these just off their onboard because they are 62ohm and they think that's nothing. But as you all should know, sensitivity is what makes a headphone hard to drive more than impedance. If you run the power calculator, these require identical power to the 300ohm HD6XX. They aren't that hard to drive, but harder than people give them credit for. I hate the stock wire, 10ft wires are always a no for me. If you are running them onboard from the back of your PC. then yes you might want a 10ft cable, but if you are running them off an Amp on your desk as you should be, a 10ft wire is way too long. It is also thin and spaghetti like and twists up and is very janky, if you get these please consider buying a shorter replacement from Periapt (linked below). The wire is a 3.5mm with a screw on 1/4in adapter. The box they come in is decent, with a plastic window to see them, and velvet lined plastic holding them in place. As for leak, they are open and leak as much as the HD6XXs if not more.
 
Overall Sound:
These sound similar to the HD6XXs to me, but they are bit different. I'm not going to say they are very similar, only reminiscent.
 
Mid Range:
These headphones are still what I would called veiled. They aren't as veiled as the 6XXs, but still aren't super vocal forward. The vocals also aren't that clean, they tend to be a bit muddy and have a grain to them. They do vocals decently, but not the most pleasing ever. (Mid Range: 6/10)
 
Treble:
These headphones have more treble than the HD6XX, but it is dull. The 6XXs despite the roll off, have this crispness and sparkle, that these just don't have. They usually sound very bland and meh with strings. (Amount of Treble: 6/10) (Treble Quality: 5/10)
 
Bass:
These headphones have a decent amount of bass, more than the 6XXs by a fair bit. It is also fairly clean and focused.and enough for them to be enjoyable for EDM and for some fun in gaming. We aren't talking Monoprice Retro murder bass here, but still very good. (Bass Amount: 6.5/10) (Bass Quality: 7/10)
 
Sound Stage:
These headphones have very wide soundstage, in fact out of everything I own they come in second, falling only short of the Monoprice Retros. In some songs the sound stage is really nice and it gives a sense of presence and you can feel the environment in which the song was recorded. Very nice, and I know some people say that is good for gaming, but wait till we get to imaging. (Sound stage: 8/10)
 
Imaging:
With a wide sound stage usually comes poor imaging, and these are no exception. They aren't horrendous by any means, they are decent, but they's aren't spectacular. (Imaging: 5/10)
 
Gaming:
The K7XXs are ok gaming cans. They are better than the HD6XXs for sure they have more bass and more sound stage which is good. However, they lean more towards the fun gaming headphone category, than the competitive category. They do footsteps ok, but their somewhat poor imaging hurts them with the accuracy. Granted the sound stage helps a bit with judging distance, but either than that they don't do the best. I think the less veil helps with the poor imaging and the footsteps are a bit louder than on the HD6XXs which also helps, despite them being less accurate than the 6XXs. Read my thread here to see what I mean with fun and competitive gaming headphones. (Gaming: 6/10)
 
Fostex T-X0 $149.99:

The Fostex T-X0 is a special collaboration between Massdrop and Fostex to make a tweaked version of the T50RP MK2. And yes I said that right, MK2, not the newer MK3 which I praise so much. They don't give a ton of details on what they did to tweak the sound of the driver, but they did something. Admittedly, I have never heard the MK2 T50s, so I can't say what is different. They put on very nice hybrid pads and added a comfort strap. Also, look at the all black! They are the best looking set of T50s by far. I was almost tempted to eat the cost of the T-X0s and swap my MK3 drivers into them and send them out to Modhouse to get the Argon mod. But that's for some other time.
 
Build:
The build on these is very similar to the MK3s. Overall it feels the same as in the plastic and metal headband pieces. It differs in the headband which is rubber as in typical MK2 fashion, not that it matters because your head will never touch it because of the added comfort strap. Now the strap doesn't feel very good. It isn't leather, honestly I don't know what it is. It doesn't seem to be pleather either, it's very thick and stiff and doesn't feel nearly as nice as the leather strap I got from Mr. Speakers for my MK3s. Now it being stiff doesn't hurt the comfort, more on that later. Curiously the strap is attached to the headband with torx security screws, and  I doubt many of you have those. Stock the friction adjust mechanism is far too loose and the adjustment will not stay no matter what and it is infuriating and makes the headphones unusable. I checked some forums and I saw many other people had the same issue, so it's not limited to my pair. So a Home Depot run and an $18 set of torx screw drivers later I have fixed that issue and now it works perfectly. Factor a screwdriver into the cost of these because that has to be fixed. The pads are a hybrid bad and also feel nice. The exposed wires aren't braided as on the MK3s, just plain rubber sleeving. Overall though they feel decent and a tad better than stock MK3s. (Build: 6/10)
 
Comfort:
Out of the four headphones, these are the most comfortable. I love the comfort of my MK3s, but these are even better. I also touted the comfort of my HD6XXs, but I have since docked their comfort score a point from my original review. These, despite the weight, are super comfortable. The comfort strap is wider than my Mr. Speakers one and does a better job at distributing weight across your head. Only problem is the strap is smooth, and not suede like on the Mr. Speakers strap, which means they slip if you move your head down too much. They also have less clamp than the MK3s, which is nice. And I love these pads, I like them more than the Shure 1540 pads. These aren't memory foam, but they are soft and are deeper than the 1540 pads and just feel really nice. My ear also doesn't touch the driver which is huge bonus points. (Comfort: 9/10)
 
Misc, Wires, Power, and Accessories:
As for power, these are a T50, they love their power. Now, these aren't the MK3s, they aren't that inefficient and don't require near that much power, but they still require the most power out of the four. While the MK3s need a Magni 3 minimum, the T-X0s could get by on a Fulla 2. They sit comfortably at 12:00-1:00 on my X7S compared to 3:00-5:00 on the MK3s. The stock wire I didn't like much at first, but it has gown on me. It is a 6ft version of the 10ft wire that comes with the MK3s. However, this one isn't as stiff and fixed out the kinks much easier. Also the tips are gold plated this time which is nice. It still uses the locking 3.5mm to connect to the headphone which I don't like. It also is the only one of the four that terminates in a 1/4in. The other three terminate in a 3.5mm with a 1/4in adapter, which I always prefer. I know some people don't like adapters, but I can never tell a difference between a straight 1/4in and a 3.5mmm on a 1/4in adapter. The T-X0s include a 1/4in to 3.5mm adapter which I don't like because it's not a wire, just a solid metal piece. Manufacturers, if you are going to include a 1/4in to 3.5mm adapter, please make it a wire and copy the one Sennheiser includes with the HD650s. The problem with the one Fostex included is that it is solid metal, and that creates leverage. You have this massive big metal post sticking out of a 3.5mm jack, that is just asking for it to snap off ruining whatever it is plugged into. As for the box, it's the same really cheap basic box that the MK3s come in, nothing even holding the headphones, just bubble wrap and the wire thrown in.
 
Now let's talk sound leakage. I made this it's own subsection and bolded this because it's important. Massdrop advertises these as "Closed back principal" which I didn't initially believe because I assumed they were Semi-open like the MK3s. Now once again I haven't ever used MK2s, so I don't know if this is a MK2 thing, or just a T-X0 thing, but these aren't closed or even semi-open, these are full open. On the MK3s there are three versions, the T20, T40, and T50. The only thing that differentiates them is what covers the small three vents on the bottom. On the semi-open T50s there is a thick felt, on the closed T40s it is completely filled with plastic, and on the open T20s it is just screen. The T-X0s have the same screen that the T20 MK3s have. Therefore these are what Fostex would classify as open. Honestly, even the T20s realistically are semi-open compared to other things, but just know the T-X0s are not like the T50 MK3s. Which in turn means these leak sound a good bit, if you have ever experienced open planar headphones, you know they leak sound like crazy, and these are no exception. Now it's not as bad as a full open back planar, but they still leak more than the HD6XX or K7XX
 
Overall Sound:
Overall, I don't like these headphones. They have problems, which I also thought was problem with my particular set, but after reading forums it seems most people have the same opinion. Now like the stock T50 MK3s, they are confusing. Sometimes they sound great, while other times they sound terrible. They definitely sound terrible more times than the sound great. Overall they suffer from a muddy mid range, a hollow echoey sound, and bass slam. I really wanted to love these headphones, because I love their little brothers, the T50RP MK3s, but I just can't
 
Mid Range:
The mid range on these headphones is more often than not abysmal at best. It is so muddy and nasally you almost can't believe it, but then you hit the right song and they are great. It makes no sense. Also a poor mid range usually means bad footsteps in games, but that is not the case at all as you will see later. I also think a lot like the stock MK3s they sound better louder and their inefficiency affects the mid range more than anything. I'm writing this segment of the review after doing the test tracks to get some more last minute opinions and I'm listening to random songs while I write these on the headphone that I'm currently writing about. As I'm writing this a Hamilton track came on, and they actually sound good on the vocals, not as good as the others, but not bad. But if I go back to the Dee Dee Bridgewater track from the test track segment, they are awful. I think I figured out they problem with the mid range. These headphones seem to have a reverb problem. It seems on tracks with a lot of electric guitars and a lot of reverb it clouds the mid range and ruins it. I know this is an odd style of writing, but once again as I'm writing another Hamilton track came on with more going on and the vocals are changing in clarity as the song goes. I'm now almost 99% sure that's what it is. On songs that are not busy the vocals are actual pretty decent, but if there is a lot going on they suffer. (Mid Range: 4/10)
 
Treble:
These are fairly treble heavy headphones like the MK3s. I don't think they are quite as sharp as the MK3s, but still pretty good. I actually enjoy the treble on these headphones, but I think like mid range it also gets clouded out a lot. Also interestingly, they don't seem to do great on a lot of purely treble songs, which is odd. There they almost seem a bit dull and rolled off, but in other songs that have crisp strings as background details, they do a fantastic job at reproducing those, probably the best of the four. But once again as I'm writing this I'm listening to a piano piece and they actually sound very good, so they just keep being confusing (Treble Amount: 6.5/10) (Treble Quality: 6.5/10)
 
Bass:
These headphones have a lot of bass, but not very clean bass. They have a fair bit of bass slam, where the low end comes up a bit too much and clouds out some of the other frequencies. They aren't terrible bass cans however, and work pretty good for EDM. The quality isn't very good though, it's not very focused and kind of muddy. They are the second bass heaviest headphone I own, behind the Monoprice Retro. (Bass Amount: 8/10) (Bass Quality 5/10)
 
Sound Stage:
Also a lot like the MK3s these don't have wide sound stage, But they do that weird thing that T50s do where random sounds sound far away. Not a ton of sound stage, but enough to get by. (Soundstage: 3/10)
 
Imaging:
Once again the T-X0s are confusing. I praised the T50RP MK3s as the gods of cheap and accurate imaging, and the T-X0s are not that. Some songs like Letter as you will see later, they do very poorly. But if I try another imaging test I like called "Black Satin" they actually do pretty well. Also in games they do well with footsteps as we will get to later. But they still aren't quite on the level as the 6XXs or 4XXs. (Imaging 6.5/10)
 
Gaming:
These, like the MK3s, are actually pretty good for competitive gaming. They aren't as good as the MK3s in terms of imaging and accuracy, but they do a pretty good job. Also the narrower sound stage helps bring in the vagueness. The low end is also good for gunshots or for fun games. Overall, these are pretty good gaming headphones. (Gaming: 7/10)
 
Hifiman HE-4XX $169.99:

These are a newer collaboration between Massdrop and Hifiman. They are a revival of the old-school Hifiman design which has gained some notoriety. Most notably this design had a very prevalent issue where the plastic pieces holding the cup to the headband would snap. Massdrop had fixed this with steel reinforcements.  
 
Build:
This is a well built set of headphones. I know, well built and Hifiman don't usually belong in the same sentence, but these are impressive. They feel extremely rigid with an all steel construction and a dense plastic used for the cups. Also of the blue plastic used isn't painted, so there is no worry of paint chips which was an issue on the original Hifiman headphones. The headband is using a fake alligator leather texture and is hand-stitched and feels very nice. The grills are also a very nice black painted metal. These honestly feel better built than the HE-560 or even the HE-1000. The cheapest set of Hifiman's is the best built in my opinion. But I haven't held the new style Sundara which looks well built, but I digress. I praised the HD6XX build, but these are even better and these best of the four. Just something about the solid steel construction and the weight gives them a really premium feel. Now on my set one of the screws wasn't tightened all the way and it was causing the cup to wobble, so I had to unscrew the cup from the headband and tighten the screw, but your mileage may vary. (Build: 9/10)
 
Comfort:
Comfort is a bit of a mixed bag with these. This is the old style Hifiman and there is no comfort strap, which admittedly is better than a simple headband. This are by no means terrble, they are decently comfortable, but I think a bit more padding would help on the headband. The one thing that helps a ton is the angle of the headband curve contacts a massive amount of your head which helps distribute the fairly substantial weight. The earpads are very nice, they are using the Hifiman Focus A pads, which are a hybrid pad and are angled. They aren't the biggest pads, or the deepest, but my ears don't hit the driver, so that's always good. These are pretty comfortable, but once you hit that 2+ hour mark, you start to feel them. (Comfort: 7/10)
 
Misc, Wires, Power, and Accessories:
As for the wire, I almost loved the stock wire on these headphones. It is a nice wire that's fairly thick and not janky. It also has a very low split, one of the lowest I've ever seen which I enjoy, especially compared to the very high split on the HD6XX which can almost feel like it's choking you. The problem is the cable is a 4.5 or 5ft cable. Massdrop markets these as a portable to used on your phone, so they included a short cable that ends in a right angled 3.5mm with screw on 1/4in. I really have to question this whole portable thing. For starters, they are the easiest of the four to drive, but they still aren't that easy to drive. Your phone will push them, but you will be up on the higher end of volume and it's not the best sounding. I do like the looks, they are good looking and not something that I would be embarrassed wearing in public like some crazier looking headphones, they are pretty small and somewhat elegant looking. But then we get onto sound leakage. I know a lot of audiophile do crazy mobile setups and don't care about sound leakage in public, that's why the Koss ESP950 exists, but I'm not one of those people. These are an open back planar. Anyone who knows open back planars knows they are almost speakers, they just throw sound out of the backs. Out of the four these leak the most sound by far and if you are in any quiet environment people will hear your music. As for the box, this is the second nicest box. The inside is nothing special, and there is no presentation box like the 6XXs, but it is a nice solid feeling box with a slide on lid. Also of note these headphones can be run Balanced, which I have done through a Periapt cable (once again linked below) I don't think balanced on these makes much difference, unlike on the 6XXs where it makes a big difference, but that is still the cable I use any other time outside this showdown because it's longer and a nicer cable and no harm in using balanced.
 
Overall Sound:
These are a fun headphone. They have a very nice sound that I think most people will like. There is a ton of speculation which drivers these headphones use. Most people think even a totally new driver for these, or the HE-400i drivers. I have heard the HE-400i before, and they do remind me of those. But the frequency graph is almost identical to the more expensive HE-400S, which I have not heard, so the jury is still out on that.
 
Mid Range:
The mid range on these is good. It is very forward and pleasing, especially compared to the veiled HD6XX and somewhat veiled K7XX, and they don't have the echo or oddness of the T-X0. Now they aren't the cleanest vocals, the HD6XX takes that award, but they are still very good. They just have this tiny bit of compression, but different from the grain of the K7XX. Still though you will enjoy the vocals on these. (Mid Range: 7/10)
 
Treble:
These headphones have a fair bit of treble, and the most of the four. But it isn't in the painful realm by any means. Strings sound good and crisp. I think they maybe quite aren't as clean or crisp as the HD6XX, but way more pronounced.They are very enjoyable, and I'm sure most people will like them. (Treble Amount: 7/10) (Treble Quality: 7/10)
 
Bass:
These headphones have bass, but not a massive amount. These aren't what I would call an example of "planar bass". They have more bass than the HD6XX, but not as much as the K7XX or T-X0. The bass is very clean and focused however, and sounds great. But these aren't for bass heads and probably not the best for EDM people. (Bass Amount: 6/10) (Bass Quality: 7/10)
 
Sound Stage:
Initially I wanted to say that the HD6XX and HE-4XX sounded equally as wide, and I still think that is true for the most part, but these have that planar quality. Every once in a while you get that song and these sound wide, and they sound amazing. Many Deadmau5 tracks do this thing that gives them sound stage. Overall because of this I have to give them a point over the HD6XX for sound stage, and they are the 2nd widest of the four. (Sound Stage: 6/10)
 
Imaging:
Imaging on these is about the same of the HD6XX if not slightly better, and that's a good thing. These do a great job of left to right and front to back, which really helps them in games. They image well enough, not MK3s, but still good. (Imaging: 7.5/10)
 
Gaming:
These are great gaming headphones. Out of the four this is probably the best competitive pair. Their somewhat limited bass prevents gunshots from clouding the mid range which is very pronounced which really brings up those footsteps. (Gaming: 7.5/10)
 
Summary of the Four:
This is a new section I'm including because I want to summarize these previous sections in a way that compiles my thoughts and ranks them in terms of build, comfort, and other factors, as well as ranks them in the sound categories.
 
Build:
1st: HE-4XX
2nd: HD6XX
3rd: T-X0
4th: K7XX
 
Comfort:
1st: T-X0
2nd: HD6XX
3rd: HE-4XX
4th: K7XX
Note that the HD6XX and HE-4XX are close in comfort, there's just a marginal difference, where the K7XX is much worse.
 
Stock Wire:
1st: HD6XX
2nd: HE-4XX
3rd: T-X0
4th: K7XX
 
Box:
1st: HD6XX
2nd: HE-4XX
3rd: K7XX
4th: T-X0
 
Hard to Drive:
1st: T-X0
2nd: HD6XX
3rd: K7XX
4th: HE-4XX
 
Mid Range:
The mid range on these is tougher to rank, the HD6XX has the cleanest, while the HE-4XX has the most pronounced, so I'm going to split this into cleanliness and presence.
 
Vocal Cleanliness:
1st: HD6XX
2nd: HE-4XX
3rd: K7XX
4th: T-X0
 
Vocal Presence:
1st: HE-4XX
2nd: K7XX
3rd: HD6XX
4th: T-X0
 
Treble:
This will be split into cleanliness and amount.
 
Treble Amount:
1st: HE-4XX
2nd: T-X0
3rd: K7XX
4th: HD6XX
 
Treble Cleanliness:
1st: HD6XX
2nd: HE-4XX
3rd: T-X0
4th: K7XX
 
Bass:
Split into amount and cleanliness.
 
Bass Amount:
1st: T-X0
2nd: K7XX
3rd: HE-4XX
4th: HD6XX
 
Bass Cleanliness:
1st: HD6XX
2nd: HE-4XX
3rd: K7XX
4th: T-X0
Note that on 1st-3rd they are all more or less equal on quality.
 
Sound Stage:
1st: K7XX
2nd: HE-4XX
3rd: HD6XX
4th: T-X0
 
Imaging:
1st: HE-4XX
2nd: HD6XX
3rd: T-X0
4th: K7XX
 
Gaming:
This category I'm not doing a ranking per say, because this depends on what you want. If you read my gaming headphone misconception thread, you'll know that I said there's two main types of gamers, the competitive gamers, and the fun gamers. I now think that there is a rarer type of gamer, and that is what I'm going to call the artsy gamer. That is someone who plays simpler, mostly single player games, that are more of an art piece type games and have very high fidelity audio. I would put Subnautica in that type of games. So if you are that type of gamer, take the HD6XX. They have a very high fidelity relaxing sound, and will suite you well for that type of game. They don't have enough bass or sound stage to be fun, and while their imaging is good, their footstep reproduction isn't good enough for competitive. If you are a fun gamer, I'd take the K7XX. They don't do the best job with footsteps, but they have a good amount of bass and a wide sound stage. The T-X0 I think can fit either fun or competitive, they do a good job of footsteps for competitive, but do a great job with footsteps, only issue is the somewhat narrow sound stage that some might not like, but doesn't bother me. The HE-4XX is probably the bass all around competitive cans here. They don't have a ton of bass, but have decent sound stage, really good imaging, and great footstep production which makes them ideal for competitive.
 
Test Tracks:
All are FLAC in either 16/44.1 or 24/96. All were listened to with their stock cables on my Aune X7S and Grace Design SDAC.
 
Phil Collins' This Must Be Love:
 
Phil Collins does very beautifully recorded and mastered tracks. This is a good test of vocals as well as micro details and background details.
 
This track was hard to pick a winner, which is a theme that will probably carry throughout the rest of the showdown because I find it hard to A/B/C/D test headphones, but I will do the best I can. Immediately the T-X0 falls flat here. It's very hollow sound comes out and makes the vocals sound not all the great. Not a terrible job in background detail, but the poor vocals kill them here. The two that pull ahead are the HD6XX and HE-4XX. The K7XX also sounds pretty good, but it is slightly muddier than the 6XX and 4XX and has grainier vocals. The 6XX has maybe slightly cleaner vocals, but the 4XX has a more forward presence and better emphasis on the drums in the background. Honestly, this one is really a toss up between the 6XX and 4XX, but if I had to pick it's going to be the HE-4XX.
 
Winner: HE-4XX
2nd: HD6XX
3rd: K7XX
4th: T-X0
 
Yosi Horikawa's Letter:
 
This track will make it in probably everyone of my reviews as it is my favorite track to test sound stage and imaging. Once again the only thing that matters is the first 30s.
 
In this track I can't pick a winner, simply because it depends on what you are looking for, sound stage or imaging. T-X0s have the narrowest sound stage and the poorest imaging from left to right in this song, so if you want a definitive looser, that is it. After that it gets interesting. The K7XX no doubt has the widest sound stage, but it's imaging isn't spectacular. The HD6XX and HE-4XX have nearly identical sound stage and their imaging is almost identical too. After listening to both a few times I think the HD6XX might be a tiny bit smoother from left to right, but it is so close. So no winner here, just depends on what you want. K7XX for width, HD6XX or HE-4XX for imaging.
 
Dee Dee Bridewater's Why Am I Treated So Bad:
This is a nice and fun upbeat jazz track with vocals, electric guitars, and drums.
 
Off the bat, T-X0s suck, I listened to about 1min of the song and gave up. Narrow, hollow, and muddy sounding, these loose here hands down. K7XXs, widest, and the most bass on the drums, but dull guitars and slightly grainy muddy vocals. HD6XXs, very clean vocals, despite the veil, as well as pretty good sound stage and good sounding guitars. HE-4XXs shine again, I was getting bored of listening to this song, being that the 4XXs were the last pair I listened to on this song, and they got me excited again about listening to it. Vocals are not as clean as the HD6XXs, but they are more forward and fullers. Also they have more low end for better sounding drums, they sound wider in this song and the guitars have more presence thanks to the increased treble. I think the 6XXs have cleaner treble, but it is rolled off, where the 4XXs not so much.
 
Winner: HE-4XX
2nd: HD6XX
3rd: K7XX
4th: T-X0
 
Deadmau5's Moar Ghosts 'n' Stuff:
Test of low end, and how headphones preform for those of you who like EDM.
 
I have said it before, and I'll say it again, I don't like the HD6XXs for EDM. They just have very little bass, they are doable, but really fall flat on this song. The HE-4XXs also don't do amazing on this track either. They have more bass than the 6XXs, but both of them have a narrower sound stage that makes the violins off in this distance sound close and not as pronounced, they both however do well with the electronic sounds. The K7XX did surprisingly well here, it had ample bass for EDM and was enjoyable, I also loved the wide sound stage for the violins off in the distance. The shocker here was the T-X0s. They have the most bass by far, and it was really getting up into that head thumping level, not Monoprice Retros, but still very good. Also they did their odd thing T50s do, where they have narrow sound stage except for certain sounds, and the violins on this song sounded the furthest away and the most pronounced by far. Only problem was the electronic sounds sounded a bit off, but I think most people will forgive that for the bass.
 
Winner: T-X0
2nd: K7XX
3rd: HE-4XX
4th: HD6XX
 
Alexandre Tharaud's Suite bergamaque, L. 82: III. Clair de lune:
This is a classical piano piece to test treble as well as how they preform in soft gentle music.
 
This was an interesting piece. For starters the K7XXs fall flat here with very dull treble and not a very crisp sound. The T-X0s did surprisingly well, they sounded better than the K7XXs, but had that odd echo. Then once again we are back to the HD6XX vs HE-4XX. Like I always say the HD6XX is the kind of classical, and they don't disappoint. The 4XXs have more treble, and it is a bit sharper, so the piano is more pronounced. But the 6XXs just have this little something, this crispness, that the 4XXs can't quite match.
 
Winner: HD6XX
2nd: HE-4XX
3rd: T-X0
4th: K7XX
 
Alan Silvestri's The Oasis (Ready Player One Sountrack):
This is a very well recorded orchestra piece, because we need one of those in here. Decided to go with this over a Hans Zimmer piece I would usually include.
 
In this song none of them did particularly bad. The T-X0s, once again just didn't have the presence or clarity of the other 3, so they take last. The K7XX put up a fight this round, overall the sound wasn't quite as crisp as the HD6XX or HE-4XX, but the sound stage shown. This song has chanting, which you traditional associate with something like a massive cathedral.Something about the width of the K7XXs just sounded right in this song, and it made up for their slightly less clarity. As for the 6XX and 4XX they were so close, but this is more of a classical piece, and I think the 6XX just slightly edges out the 4XX, but it really is a tossup.
 
Winner: K7XX
2nd: HD6XX
3rd: HE-4XX
4th: T-X0
 
Diana Krall's Like Someone in Love:
Just a very pure vocal test track, simple as that.
 
This was the toughest one of the group. Know that the rankings they get are very close to one another, there is no massive looser on this track. T-X0 actually sounded decent. The vocals however, were a bit nasally and the bass (instrument bass in this case) isn't as pronounced. The K7XX sounded very good too and didn't sound that grainy and the soundstage actually sounded great. Then the HD6XX come in and almost bring a tear to you eye with their super crisp vocals and production of the strings. But then there are the HE-4XXs, they did something that no other headphone did. They produced an echo of the vocals way off in the left channel that I had not heard on the other three that I had listened to before them. I went back and had to check myself. The K7XX and T-X0 didn't reproduce this echo in the slightest, while the HD6XX did if you really listened for it. That would normally give the 4XXs the win in one of my shootout, doing something amazing like that, that no other headphone did. But I found their very forward vocals a little to sharp and intense in this song, yet still very good. The HD6XX is just a more beautiful rendition here. Once again, these are all very close and their ranks aren't far apart.
 
Winner: HD6XX
2nd: HE-4XX
3rd: K7XX
4th: T-X0
 
Conclusions:
Well this has been one heck of a battle, and if you have made it this far, thanks for reading you now get to know my final thoughts  (unless you skipped here, then IDK then  ). The first thing you are going to ask me to do is pick a winner, and I simply can't, because there are a lot of factors in play. First let me get a few things out of the way.
 
For starters, I don't recommend the Fostex T-X0. I'm sorry I have to say this, but they really just don't sound very good. They have a very hollow and nasally sound, which isn't pleasing at all. I don't think they are worth their $150 asking price, especially compared to other offerings. Not that this really matters, because the T-X0 is the rarest of the 4 by far. I think there are only around 2000 pairs ever made, and they drop extremely infrequently and in low numbers, so most likely you will be buying a used set. Maybe if you can get them around $100 they aren't the worst ever, but still not recommended. I think the only person they fit is someone who only games and listens to EDM, either than that I don't think you should get them. Also they require the most power and you will need an amp. Now if you ask, well I can get the stock MK3s for $10 more, which should I get? T-X0s, hands down. Why? Not because of sound, but because the stock MK3s are the most uncomfortable headphones ever. Now if you asked, T-X0 or MK3 with 1540 pads? MK3s by a mile, they sound much better stock than the T-X0.
 
The AKG K7XX is the interesting pair here for one reason, it is always in stock. If you buy them, they ship next day. If you buy HD6XXs, HE-4XXs, or T-X0s, you are waiting months, where the K7XXs you will get in mere days. I never hated them in anything but comfort and build, but they didn't do amazing at anything and I think they have a few issues with the sound. They will get my recommendation, but I think they need a pad swap and a new cable which pushes them close to $300, and at that point you're a moron for not buying HD600s. But if you can live with them stock, they aren't the worst thing ever. Are they better than HD598s? Eh...It's hard to say, I'd have to have a set for side by side comparison, but from memory I think they are a tad better. If you can't wait, they get my recommendation, but I think they are overrated. 
 
Now if you can wait and have $200 to spend, the question becomes, HD6XX or K7XX? HD6XX in a heartbeat. They massively outclass the K7XX in nearly everything. Overall they are just a much cleaner sound, and a far better headphone. There's a reason these have been around for 15 years, they are amazing headphones. I think most people will really like them, they have such a smooth and relaxing sound, and are still probably my favorite headphones. These get my highest honor of recommendation, if you don't have a set, buy them.
 
Now before the HE-4XX came, I thought the HD6XX was going to sweep, but as you saw the HE-4XX put up one heck of a fight. They are so good, where I am seriously contemplating if they are better. The real million dollar question of this whole showdown is HD6XX or HE-4XX? I have concluded this.
 
Which to gets depends on what you want and a few factors. For starters, do you want to get into audiophile headphones and get multiple pairs? Or do you just want one pair and to be done? If you want to get into collecting multiple pairs, get the HD6XX. They are the HD650 which is the universal reference point that everything is compared against and you need to have a pair in your collection if you are an audiophile. Now what if you want one pair? Well that's where it gets hard. You will enjoy either, but frankly I think the HE-4XX has a sound signature that more people will enjoy. Personally, I still think I prefer the HD6XX because it's sound caters more towards the type of music I listen to. But the HE-4XX has more bass, more forward vocals, more treble, more sound stage, and slightly better imaging. They also are better gaming headphones. Overall I think that sound signature matches more music genres then they laid back HD6XX which is the kind of classical and old time music, while being very bad at pop, rap, and EDM. The HE-4XX does a great job with pop and rap, and a decent job with EDM. I think the HD6XX is more comfortable once you fix the clamp, but neither are bad. As for power, the HE-4XX is easier to drive, but you really should get a DAC/Amp for both. All you need is a Fulla 2, that will drive both perfectly fine and you will be happy with either. Also the HE-4XX is $30 less, and ships quicker than the HD6XX. So which one of those to get is ultimately up to you. Both of them get my highest recommendations and both are amazing.
 
Now at the end is the collection update, what's staying and what's going. I say that it's an honor for a headphone to earn a spot in the collection of a starting out reviewer like myself, because otherwise I can sell them and move onto something else. The HD6XX earns the most permanent spot you can get, like I said they are the reference point you have to have, so those will never be sold. The T-X0 will be sold, I love the look and the comfort, but the sound isn't very good and they are destroyed by my Mayflower MK3s. K7XX is also going to be sold, I have no need. They don't do anything special and don't fill any gaps in my collection, I have no need for them. The HE-4XX is here to stay, at least for now. I love these headphones, but there are better open back planars. I've heard better open back planars,so down the road if I ever get a set of something higher end, these might go. But under $200, these are the best planar headphones you can get. These are better than M560s, M565s, M1060s, and even stock MK3s with 1540 pads. Before you ask if these are better than Mayflower MK3s, stop, those cost way more.
 
Anyway thank you for reading my review. I hope this was helpful to everyone looking for headphones on Massdrop. I do intend to review the new Sennheiser HD 58X Jubilee if I can grab a second hand set in the next few months, because that is another $100-$200 Massdrop headphone, so stay tuned for that. I also have another big review in the works in the next 2-3 weeks, and trust me, you won't want to miss it. Everything used will be linked below. Also I will link my HD6XX vs T50RP MK3 review, and stay tuned for HD6XX balanced vs T50RP MK3 Mayflower.
 
Sennheiser HD6XX
AKG K7XX Black
AKG K7XX Red
Fostex T-X0
Hifiman HE-4XX
Aune X7S
Grace Design SDAC
Periapt Cables

Micca Origen G2 pretty good alternative.

Since you mentioned you would like to listen to it with your phone walking around campus it means you are looking for headphones to also listen to music. Then those gaming headphones you mentioned are definitely not for you. Also it means you're looking for closed headphones unless you want to walk around having people hear what you're listening to. I would recommend the Superlux 669 and Status Audio CB-1 as mentioned above and a seperate mic.

Here you go. Headphones that people can't see

The k5 is not a dac amp combo it's only an amp. You would need a FiiO portable player to dock with it to act as a dac.

Don't get the Samson. It may be the same headphone (with better pads) as the Superlux but it is even more cheaply built with a flimsy thin nondetachable wire unlike the Superlux.

IFI Nano IDSD Black Label it has a better DAC than the Schiit Stack and O2. It can drive headphones up to 600 ohms so it can drive your 650s just fine. It's also portable with up 10 hours of batterylife even though it's pretty thick for a portable (looks better on a desk). A more in depth review here

I don't typically review DACs or Amps because normally I don't find them that interesting to review. It's also hard to find things to talk about in comparison to another Amp, especially when comparing two of similar quality. When I will review a DAC or an Amp is when I come across one that truly stands out to me as special or different. I have recently came across a portable DAC/Amp combo that I think is worth your time to look at. In fact, I am going to tell you to buy it over a Schiit Stack. I'm talking about the IFI iDSD Nano Black Label.
 
IFI iDSD Nano Black Label: $199

 
The Nano as I will refer to it as for the rest of this review is a $200, portable, battery powered DAC/Amp combo unit made by the England based IFI Audio. This unit has some amazing things going for it and a few flaws.
 
It comes in a nice box with the unit, a black velvet carrying bag, a 3ft blue colored USB 3 male to female cable, a solid USB A female to USB type B adapter, a 6in flexible USB A female to USB type B adapter, and 2 rubber bands to strap this to your phone or player. As for the size the Nano is a little smaller than a deck of cards in length, but a tad thicker. It is made of black aluminum and it feels very solid.
 
Starting with the overview of the unit, you will find nothing on the top or sides besides a logo and some writing. On the front you have the volume knob that also acts as the power switch, only complaint is I wish the volume indicator had some sort of texture so I could feel where it is in the dark. There is a LED that will change colors depending on if it is running off of USB or battery power, it also will change depending on the bitrate of the music and if you are using DSD, DXD, or MQA (more on this in a bit). Then on the front you will find 2 outputs, both 3.5mm. The first is labeled direct, that is very simple, it is just the full power output of the device. The second is labeled IE Match, this is a technology that IFI uses where with some very sensitive IEMs it will limit some of the output power and try to match the resistance of the headphones, or more likely, IEMs. The problem with this port is the output impedance is 4ohm. For those of you who don't know, you want as low of an output impedance as possible, particularly so with low impedance headphones or IEMs. Most very sensitive IEMs such as the Campfire Andromeda (which are 12ohm) simply have too low of an impedance for a 4ohm output impedance. What happens if your output impedance is too high for your headphone impedance is the pitch of your headphones also gets thrown off. You would need at least 32ohm IEMs to use this port. I tried IE Match with the one pair of IEMs I have, as well as a few other easy to drive headphones such as the Koss KSC75 and Phillips SHP9500S, and with those the music would get loud enough, but it would be near maximum. I never got any of the hiss that some people claim out of direct so your mileage may vary, but I would just recommend using Direct and forget about IE Match.
 

 
Now for the really interesting thing, this is a balanced headphone Amp. IFI has been pushing using a 3.5mm 4 pole as a balanced connection, and that is quite interesting. Many people agree that the 2.5mm balanced typically found in players made by Fiio, Hifiman, and Astell and Kern, is too fragile of a connection because it is so small. Sennheiser and Sony have been pushing the new 4.4mm Pentaconn 5 pole connector, and IFI is going with 3.5mm 4 pole. IFI doesn't claim more power using balanced as opposed to unbalanced like many Amps do, so the only benefit of going with balanced is the usual benefits of balanced if you believe in them. The problem with 3.5mm balanced is IFI is the only one who uses it to my knowledge and therefor there are no headphones cables for it. You'd have to make your own or have someone make one for you to use it. I wish IFI would of either included a 2.5mm 4pole to 3.5mm 4 pole adapter, or at lease sold one separately. Heck, I would of even take a 4pin XLR to 3.5mm 4 pole. Anyway, I have no 3.5mm 4 pole cables so I haven't tried balanced on this unit, so I can't speak to how well that works. Another thing I though of that IFI should have done by using a 3.5mm 4 pole is make this take a mic input. I don't know if it would be possible to make this have a 3.5mm balanced and a mic input at the same time, but that would be really cool sine this thing will always be hooked up via USB. That would make this the best gaming DAC/Amp too for people who use the Vmoda Boompro I often recommend. IFI, for the next version see if you can make this thing take a mic input, if not ditch the balanced and add the mic, that would be a much more used feature.
 
Flipping around to the back of the unit you will find a full sized USB 3.0 A Male. In order to hook this unit up, you have to use either a USB 3.0 male to female cable, or an OTG cable to use it with your phone. Next you will find a switch that says "Measure" or "Listen" leave it on listen and don't worry about why it's there or what it's for (otherwise I'd have to type another few paragraphs explaining it). And finally, you will find a 3.5mm line out. A line out is for if you want to use this as a DAC on another Amp, which I highly recommend as you will see in a bit. Line out if the full signal of the DAC, so the volume knob does nothing to control that, which is awesome for using it with another Amp, but not good if you want to use it with powered monitors in which case you would need a separate pre-Amp.
 

 
As for a few more general usage items, as mentioned earlier this is USB only and there is no analog input so you can't use the Amp with another DAC. As for it being battery powered, this means it can be used with with your phone with the use of an OTG cable. When you use it on your PC plug it in first and then turn it on, this tells the Nano to use USB power. When you are using it with your phone turn the Nano on first and then plug it in, this tells it to use it's battery power. As for battery life, I haven't fully drained it, but from what I've heard it's 4-6 hours depending on how hard your headphones are to push. As for using it with your phone, I find it a bit thick to strap on the back of your phone, it's not thin like a Fiio Q1 MK2, or Oppo HA-2SE, but it is doable.
 
As for a few more specs, this is a 32bit, multibit, 192 DAC, that supports DSD 256, DXD 384, PCM 384, and MQA. Don't concern yourself with 32bit, DSD, DXD, PCM, and MQA. As for power, the Nano claims 285mw at 32ohm, and 20mW at 600ohm. This isn't a crazy powerful headphone Amp, but you'd be surprised how well it does at pushing headphones. Now, I can confirm it is doing loudness EQ. I know this because when I plug T50s in they are loud at 1:00 despite sounding incredibly distorted. If it did no loudness EQ I should be able to max the Nano and the T50s should still be relatively quiet. But that doesn't mean it can't drive headphones. Even 300ohm cans like the HD6XX and HD600 this can push quite well. Anything easier to drive this thing doesn't break a sweat. If I compare the 6XXs on the IFI to a bigger Amp, they sound just a tiny bit better on a larger Amp, but I have 0 issues with using them on the IFI. I'll give a list of all my headphones and whether or not the IFI can drive them.
 
VE Monk Plus: Yes
Koss KSC 75: Yes
Sennheiser HD500A: Yes
Monoprice Retro: Yes
SHP9500S: Yes
Hifiman HE4XX: Yes
HD600: Yes
HD6XX/HD650: Yes
T50RP MK3: HAHAHAHAHAHAHAHA NO
Monoprice M1060 V2: Yes
1More Triple Driver Over Ear: Yes
Hifiman HE560: Ehhhh.....More or less
HD660S: Yes
 

 
As you can see it does a pretty good job at driving headphones. As for the sound quality, I have no issues using this over anything else on my desk. It's not quite as good as say a modified Lyr 2 fed by a Yggdrasil, but still it is exceptional. For it's price, I have no reservations saying it's a higher quality Amp than the Magni 3, and I will say without question this is a better DAC than the Modi 2. Not it is not as powerful as a Magni 3, that is for sure, but it pushes even relatively hard to drive cans quite well. As for the DAC, it's a higher bit rate DAC than the Modi 2, it's multi-bit, and it supports more formats. Not that any of that really matters, but to me it sounds better than a Modi 2. This is where I am going to tell you to buy this over a Schiit Stack. This is the same price as the non-Uber Schiit Stack. So what do you loose for the same price. Power, and pre-outs, that's it.The Magni 3 has a lot more power, which if you need the power, you need it, i can't blame you there, but if you don't take the IFI. Then the IFI can't be used as a pre-Amp for powered monitors, you'd need to buy another pre-Amp, but I doubt too many of you care. Both the Nano and the regular Modi 2 are USB powered, but the Nano has USB filtering where the Modi 2 doesn't. I have gotten 0 USB noise out of the Nano which is something I can't say about my other USB only DAC, the Grace SDAC. I would take the Nano over the Modi 2 as a DAC any day. Now if we compare the Nano to the Uber Schiit Stack and swap out the standard Modi 2 for the Modi 2 Uber, there you gain external power which helps with the USB noise, and optical if you really need that, but that's still $50 more than the Nano and I still prefer the sound of the Nano. 
 
In my opinion, the Nano is the better buy over the Schiit Stack, unless you need power. If is small and works very well on a desk, and boy does it sound good. What I would recommend is unless you are going right out for crazy hard to drive stuff like T50s or 600ohm Beyerdynamics, get the IFI over the Schiit Stack. Then down the road if you need more power, buy a Magni 3 and use the line out of the IFI to feed the Magni, or if you want a tube Amp, say a Darkvoice or Valhalla 2, feed that with the Nano. Then you have a powerful Amp for your desk, and an amazing DAC/Amp for on the go. Just unplug the USB and 3.5mm, plug in your OTG with you phone and go. It is a more convenient and better solution in my opinion. I promise, you won't be disappointed in the sound. I used this as my only DAC/Amp for an entire week when I was on vacation, and I never once questioned the quality. Another thing I like to do with the IFI is use it to listen to headphones in bead, that is something many of you can't do with a Schiit Stack. Loosing power over the Magni 3 is worth it to me to be able to go anywhere with high quality audio. You will never need to question your phone or laptop audio ever again.
 
Hope you found this helpful, and I hope I sold you guys on the IFI iDSD Nano Black Label. I will link it, as well as a few other things below.
 
IFI iDSD Nano Black Label
1st Party Lightning OTG Cable
Generic Lightning OTG Cable
USB C OTG Cable
Micro USB OTG Cable
3.5mm to RCA to use with another Amp
1/4in to 3.5mm Adapter.
1More Triple Driver Over Ear (My Portable Headphone Most Often Used on the Nano)
Periapt Cables (If you want to get a custom 3.5mm 4 pole cable)

Very nice! I’m buying the HD58X today. Apparently there is a mod that makes them sound almost identical to the HD660S. I will be reviewing them shortly and I’ll let you know how they compare.

I decided to keep the 660S and got the Q1 MKII for it. Thanks a lot your review was very informative.

I decided to keep the 660S and got the Q1 MKII for it. Thanks a lot your review was very informative.

SHP9500s

Soundstage+Imaging > 7.1

hurry
https://www.massdrop.com/buy/massdrop-x-mee-audio-pinnacle-px-iems
 

I don't usually trust amazon reviews and those look like they're trying to be Beats

Look for Brainwavz earpads on amazon. It's your choice on whether you want leather, velor, angled, etc. They are generally around 20+ bucks pricey but worth it. The clamping force of the Monoprice with the stock pads will make it unusable for you with glasses.

I'd go with the Monoprice.
Monoprice 108323's pads are known to be uncomfortable as hell though so I'd recommend getting replacement pads. I haven't even heard of the other 2 choices.

From what I've read the 900x has better bass and vocals than the 700x making it a better headphone choice for what you're looking for. Not sure about the 900x vs the ADG1x in terms of sound but the ADG1X does have a really good mic.