Cozoy REI Mini DAC Headphone Amplifier DSD256 32bit/384khz for for Android/iOS/PC/Laptop/iPhone7

Pros: Small. Good sound from a smart phone or PC. High-res capable (PCM and DSD). Quiet even with sensitive IEMs.
Cons: Power output very limited. Relatively expensive.
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At one of the Tokyo headphone festivals I met the guys from Cozoy in Hong Kong with whom I was discussing headphone EQing, as they had Head-Fi member and FiiO representative Joe Bloggs headphone EQ system, which I have long been curious to try. While I was talking to them, I tried out their prototype for the Rei which plugs into a smart phone, iPhone or computer and plays back pretty much every format out there, from CD quality to high-res and DSD. That product did a remarkable job with the JH Audio Laylas. 
 
Let me get this out of the way from the start: The Rei is tiny. While not quite as small as the finger-width Aegis, We’re talking three-sticks-of-gum small aluminium enclosure, only barely thicker than the 3.5mm headphone socket, inside of which is a full DAC/amp that can be connected via one of three included USB connectors (A-micro, micro-to-micro or Lightning to micro) and play back music up to 24-bit 192k or at least DSD64 (as DSD256 taxes the capabilities of a smartphone too much, that output might be limited to your computer). On the amp side, given it is has to be powered by the phone and not cause your iPhone to complain about excessive power consumption, it is limited to 60mW of power output at 16 Ohms, and 35mW of power at 32 Ohms. No problem if you have a portable amp, but if your headphones are sensitive enough it may be enough on its own.
 
An interesting thing to note is that, according to the company, even though the included Lightning cable does not have a CCK (Camera Connection Kit) built in, the Rei is designed using an "official" method for connecting devices to an iPhone, which should continue to work even with future iOS updates. They said that it also uses less battery power than a CCK does. In using the Rei, it did work fine both before and after a major iOS upgrade on my iPhone 6.
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Initially out of the box the sound was quite warm. It was suggested that I give it some time to "burn in" so I left it playing music for a couple of weeks. After that time the sound opened up. While it still is a bit on the warm side, especially with DSD, I found it impossible to guess which DAC chip it used without asking, such was the musicality of the delivery. What was most noticeable was the difference in sound quality using it with my iPhone versus using it from my iFi iUSB 3 which provides much cleaner power. 
 
From the iUSB 3.0 the sound was much clearer. I was told that the power supply in the Rei was very carefully designed and it shows in the graceful degradation in sound quality, never becoming harsh, only losing detail.  Importantly, the Rei is dead silent with IEMs, even the very sensitive Campfire Andromedas. 
 
Where it is limited most is in output power. While it drove both multi-BA and dynamic IEMs and sensitive headphones sufficiently, adding an amp into the chain improved clarity noticeably. By itself, the Andromedas sounded a bit closed-in, the music more a sound blob. With the Pico Power providing amplification the soundstage (as far as IEMs can have one) widened and clarity improved. 
 
This lead me to ask about the in-built volume control, as I wanted to know if it would affect output quality when used with an amp. It turned out that the volume control is analog, not digital so that it can be used at any volume level without potentially degrading the sound.
 
Cozoy_Rei-02417.jpg
 
My usual test with DACs is to try them with CD-quality music both straight and up-sampled using iZotope (built into Audirvana Plus). For the Rei I could also try DSD up-sampling. In most cases this provides an improvement with instrument realism, such as it did with the Aurender Flow. I was surprised with the Rei that up-sampling didn't seem to change things noticeably. DSD re-sampling not surprisingly made the sound slightly smoother as was expected, as did listening to DSD masters. 
 
The only other device I have close to its price is the Chord Mojo, which has considerably better headphone drive and a more resolving and natural-sounding DAC, but is also considerably larger. 
 
Cozoy_Rei-02410.jpg
 
At US$550 the price is quite steep, especially when you consider the competition from companies such as Audioquest and Centrance and especially Chord. Where it will be best is for people who really want a small, high-res capable device where even something like the Mojo would be too big, and one's headphone driving demands are only minimal (or one is going to use an amp).

ExpatinJapan

Headphoneus Supremus
Pros: Hi-res with no CCK, excellent sound on all fronts, small footprint, array of cables
Cons: no battery

Cozoy REI Dac/Amp Review - Expatinjapan

 
Cozoy REI with ipod touch 6G, Flacplayer app and Campfire Audio Vega IEM.​
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Cozoy REI review​

A little wonder, a mini beast of a machine​
-expatinjapan​
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Cozoy REI with ipod touch 5G, Flacplayer app and Shozy Zero earphones.​
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Unboxing
 
 
 
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Whats in the box
 
 
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The Cozoy REI DAC/Amp and ​
a suitable quality selection of cables for use with OS, Android and Computers.​
 
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Build
 
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The Cozoy REI is a solid machined aluminum CNC anodized unit of two pieces.​
 
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Very lightweight weighing in at a comfortable ​
 

The design is screw less, the two halves somehow locked together in an eternal embrace.
 
 
 
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Audio in via Micro USB​
 
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Audio out via 3.5mm jack.​
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Specifications
 
*Images via Cozoy REI website (with permission).
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for a full set of measurements and a write up see:​
http://ohm-image.net/data/audio/rmaa-cozoy-rei-24-bit​
 
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Value
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The Cozoy REI retails at US$550 (Shipped If you order direct from their website).
 
A hefty amount for such a small battery-less piece of equipment some might say.
I would agree too If I had not heard its wonderful sonics  myself first hand.
 
The Cozoy REI certainly to my ears matches price and performance that belies its size.
 
Solidly built, and very lightweight.
 
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Sound
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As usual I got a decent amount of time on the Cozoy REI before reviewing to please the burn in fans, as the anti burn in crowd don`t care. Therefore everyone is happy.
 
I tested it with a variety of sources such as lightning based ipod touchs 5G and 6G, using Flacplayer app by Dan Leehr and all the recommended Relisten app.
 
There were sessions with and iphone 6, and also a Macbook pro.
 
Sadly due to a lack of Android based phones in my possession I could not check that side of things.
 
I used mainly the Campfire Audio Vega and Andromeda, iBasso IT03 IEMs for my testing.
 
I found volume generally to be set at 50% or less. It has  a decent amount of power under the hood.
 
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The sound of the REI is linear, neutral yet portrays the music so beautifully clear, concise and realistic that it also deserves the oft thrown about term musical.
 
Musical not in the sense of any particular boosting of bass, mids or treble, but in the thrilling amount of resolution, depth and soundstage that this little beast of a device delivers.
 
Realistic is a term that springs to mind.
 
As you can tell I am well sold on the Cozoy REI. I reviewed the Aegis a year ago, the rise in quality of performance from the aegis to the REI is truly astonishing.
 
Often these days a Dac/amplifier is mostly an incremental difference in overall performance, often the extra amplifying is enough alone to stun the basic customer, plus as mobile phones themselves improve more and more it is harder to out do what many phones can give the customer in terms of sonic satisfaction, not to mention the more prickly and jaded audiophile who expects bang for their buck, and at least a product to deliver on its promises.
 
I find the Cozoy REI to be excellent, smooth, delicate retrieval of details, a solid low end which has a fast response yet lingers enough to please, mids are warm, rounded and pleasant, the highs extended enough to give a sense of extension and space.
 
The vocals are extremely rich, full of emotion and clarity and placed just right with the music. I detest vocals either too far forward or recessed.
 
I could not detect hiss with my sensitive earphones, nor could I detect any electronic interference from wifi etc.
 
The included cable while seemingly looking like a simple cable, is actually of high quality and carries the data through beautifully.
 
I found I could listen for as long as the battery held out without fatigue, results varied as to battery life due to my thrashed and over used ipod touch 6G, the ipod touch 5G having had an easier life laster much better.
 
The full bodied sound was an initial surprise to me, and still slightly shocks me as I start it each time. 
 
Instrument placement and reproduction, coupled with the overall smoothness, excellent detail retrieval, deep and wide sound stage and overall resolution places the Cozoy REI within the small select group of gear that I have truly enjoyed and loved.
 
 
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As we can see from  the screenshots of the Flacplayer app on the ipod Touch 6G,  it plays back ​
Hi-Res tracks natively with no down sampling, and without the need of a CCK cable.​
 
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reicomputer.jpg REI connected to a Macbook and iBasso IT03
 
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Overall
 
The Cozoy REI is small in stature yet huge in sound.
 
It is true the market is turning more towards separate Daps it seems, but there is still a demand for portable DAC/amps that especially pair well with our mobile phones on the go.
 
Even five years ago it would have been unthinkable for a DAC/Amplifier to be of such a size, and still pack the power and sonic depths of the earliest large and hefty models. 
The earlier models and also until most recently seemed to be locked at 16/41 or 16/44 depending on what site one visited, mostly due to Apple various restrictions. Even most apps that touted and still tout to ply back Hi-Res natively more often that not, did not, even when connected with a Camera Connection Kit (CCK).
 
And now we have the REI. Small, powerful, with a large, deep and detailed sound reproduction that plays back Hi-Res files with Apple products natively.
Quite an achievement in itself.
 
Its earlier siblings the Astrapi (somewhat weak in performance), the improved Aegis (Whose Achilles heel was its sudden volume jump, a quick fix being to use the Kaisertone  or Relisten app), were precursors of the REI, who so far seems to have reached a summit in performance with none of the issues of its predecessors.
 
It even gets the thumbs up from the strict Ohm Image site!
 
I recommend the REI as a portable DAC/Amp, whilst its battery less construction no doubt is a drain on whatever device you may commute with, I found I could reach my place of employment without the music ending, safely arriving to recharge my portable device. Anyway, I like most mobile users these days don`t go anywhere without my portable battery pack anyway.
 
I have written enough about its many virtues in the sound section, some what flowery at times as the REI brings out the poet in me, due to its gift of providing me with the technology to simply enjoy the music without having slight drawbacks in reproduction draw me out. 
 
It truly is a little marvel.
 
 
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Thank you to Cozoy for sending the Cozoy REI for review​
-expatinjapan​

Jimster480
Jimster480
How does this work with a windows PC driving it? Has anyone tested it? And how is the battery life of an iOS device powering it? I have a FiiO K1 and it sucked down the battery of my iTouch 6G pretty fast.
br4lin
br4lin
Seems a little hard to carry around with your phone.
glassmonkey
glassmonkey
This cannot be true: easily drives "Focal Utopia, HD800, LCD3F". Anyone who would claim this simply has no idea what these sound like properly driven. 1 Vrms is nowhere near enough power to 'drive' those. Sure, you'll get sound, but they won't be properly driven. I can get sound out of my HD600 hooked up to my phone, it isn't being properly driven.
 
With regards to ease of carrying around, this is not hard to carry with your phone. It's slim and small. It will fit in your pocket with your phone. That is something that can't be said for the Mojo. The Mojo, due to its thickness isn't terribly pocketable. Portable, yes, pocketable, no. The new Poly does address some of this by cutting the cord on the Mojo and should do so without quality loss, but the price is too damn high. The key for the REI will be how much it drains your phone battery.
 
I haven't tested this, but I've tested plenty of stuff with comparable amplification power and the ability to hook up to phones. This looks like a pretty good option to me, and it looks aesthetically fantastic. There may be comparable options at a lower price, though, like the Audio Opus Opus #11.
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