Astell&Kern AK100II High Resolution Single DAC Audio Player

The AK100ii is a DAP I've had my eye on for quite some time. At first glance, it's obvious that it's a premium piece of kit, with it's clean efficient lines, quality touch screen, minimal physical interruptions, and compact size. Reading up on it's specs and the fact that it keeps (and improves) on it's previous iteration leads one to believe that for the asking price, this should be a one stop product, where a bunch of tweaking, additional cables, outboard DACs or amps shouldn't be necessary.
 
And ya know what? It lives up to the hype.
 
The Hits 

1. Support for every lossless format under the Sun
2. USB DAC capability
3. Wi-fi and Bluetooth capabilities
4. Smoothest, most natural UI I've encountered

 
The Misses

1. Physical button layout
2. FILE TRANSFER FOR MAC USERS

 
My Thoughts
 
To give you an idea of where I'm coming from, my head-fi DAP history has included a plethora of iPods, a sample of Sansas, a cache of Colorflies, a basket of iBassos, and a few Fiios. Some like the iPods, C3, and DX50 were used with additional amps & DACs, while the X3, X5, and DX90, have been standalones. 
 
For a while, the X5 was my go to as it checked off just about everything on my list. After all, most of my music is redbook quality, my main headphones are very easy to drive and I have no desire to have to carry a giant stack of gear around. Portable audio should be portable after all! 
 
Sound
 
The X5 never left me feeling like I was missing much on the sound end of things, but when a nice deal on a secondhand AK100ii came up, I pulled the trigger. Figured if for whatever reason, I didn't like it, I'd be able to move it along quickly. After giving it the full run-through with my RS1, GH1, and 1+2 however, there's no doubt in my mind that the X5 has been usurped.
 
Starting from the bottom, the bass is truly and completely audiophile quality. There's no bloat, no over-the-top sub-bass, and no Earth-shattering mid-bass lift (unless they're already in the recording). What I'm hearing is bass that is incredibly textured, articulate, fast, and dynamic. When called for, it can certainly bring the rumble, but that's only when I'm listening to hip hop or EDM which have that sound in the recording. The AK has made me realize that the X5's low end was a little warmer than I realized, perhaps to strike a happy medium between the budding audiophile and average consumer. 
 
In a word, the midrange is... neutral. I'm definitely a mid-centric listener. My entire desktop rig is designed around the RS1's incredible midrange. And while I loved the thick and lush vocals and crunchy guitars that the X5 gave me, going to the AK has shown me that I was losing out quite a bit on texture and depth. The 100ii doesn't just rush voices to the front of the mix. They stay a little further back so they sound more cohesive with the rest of the track, rather than isolated  to give them the spotlight. I'll admit sometimes I miss the warmth that the X5 lent to Norah Jones and John Mayer, but I think what I've gained in my upgrade is easing my suffering 

 
Treble. Clean, airy, textured, and sometimes, a touch too clean. If there's one sonic characteristic about the AK that gave me pause when I first received it, it was the upper end. It's incredibly uncolored and detailed. A clear step up from the X5 and the DX90. However, every once in a while the Grados and the Tralucent would get a little abrasive on abundant cymbal crashes or peaky female vocals. I added just a bit of EQ and rolled some foam tips onto my IEM's and now we're good to go. Now bear in mind, I'm a little treble sensitive, so fear not, I'm not saying that this headphone is nails-on-a-chalkboard screechy at all. It's overall presentation is very clean and neutral. It's gonna give you what's on the recording. If you've got treble-happy headphones, they're not going to be tamed. And if you've got warmer cans, the extra clarity on the upper end may be a nice synergy for you! YMMV.
 
With regards to soundstage/separation/depth/etc. the AK is the best I've heard in a portable solution. This is where I feel like DAP's really separate themselves and the AK shows that it's clearly a force to be reckoned with. Because of that ultra-clean treble, instrument separation is excellent; leaps and bounds ahead of anything I've heard from Fiio or iBasso. Soundstage width is only a little above average, but depth is quite good! The 100ii really shows off how capable the 1+2 is in this regard. 
 
Function
 
I don't care to spend too much time in this section because frankly I don't need to. I read a post recently about how a company choosing to employ the computer power of something of this caliber should make the UI almost cell-phone like and I agree... partially. If you're trying to market a premium product, IMHO premium sound is only half the battle. A premium UI is the other half. Luckily, the Android-based UI that AK has developed is very straightforward and easy to use. Granted there have been several firmware updates and as far as I know, they are still continuing to improve, but mine is running 1.25 and I don't feel like anything is missing. Menus are intuitive, controls are easy, there is minimal lag, and I've yet to experience a freeze or crash. When I rolled with the X5 and the DX90, I could navigate well enough, but I definitely felt like the UI was an afterthought. 
 
The only real qualm I have with this player is the file transfer protocol for Mac users. You have to download an app called Android File Transfer and quite frankly, it sucks. It's inconsistent. It's slow. It often hangs up. And it's incredibly limited in it's capabilities. Makes a new DAP owner a little bummed that he's got to try half a dozen times just to get his music on his player! Would love to see this little feature fixed either on AK or Android's end. 
 
I should also mention that the 'extra' features that AK chose to include are well-done EDIT: ok and appreciated. These include wi-fi capability for streaming, Bluetooth for wireless play, and USB DAC functionality that works very smoothly. The only one I really wanted was the USB DAC, but now that I have the others, I'm certainly feeling like I got more of my money's worth.
 
EDIT: Went back to further confirm these and didn't have a lot of success. They worked, but were a little inconsistent. Luckily for me, I don't use either of those functions very often.
 
Conclusion
 
In summary, the AK100ii, a.k.a. The Gatekeeper (for the land of portable high resolution listening) is a very well-made and designed product that anyone (that's ready to pony up for it's asking price) should consider. Now that it's been out for a while, firmware is very solid, and finding one on the used market makes it even more affordable. 
 
If you want neutral, clean sound with a slew of extra capabilities, then the Astell & Kern 100ii should be on your short list of players!

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Disclaimer:
 

I was provided with a free sample of Astell & Kern's DAP for this review by a local distributor.

 
Introduction:

Because of a small series of lucky coincidences I found myself on the phone with the CEO of AudioTuning, Austria's biggest audio distributor, and after a few minutes I got offered to review the AK100 II, which couldn't be declined. How often do you have the opportunity to test one of the best DAPs?
A week later my review package arrived, right after I finished my time with FiiO's second gen. X5, and at the moment this was the best sound I've heard. This was about to change very soon.
 
The box delivered what I knew about A&K. Elegance, style and absolute high end quality.
The AK100 II is the very first touch device I've used for more than just a few minutes, and it is the first I felt comfortable using, more on that in the UI section.
 
Its heart is Cirrus Logic's CS4398, the same as in the AK120 II and AK240. But the AK100 II only uses a single DAC chip. The battery has a capacity of 3150mAh, which gives the device power for about eight to ten hours. It features WiFi and bluetooth streaming.
The AK100 II has 64GB of NAND storage, which can be accessed via MTP from every Windows, Mac or Linux computer. Only about 56GB can be used for storage though.
Firmware upgrades are available through WiFi/OTA (OverTheAir). My device was running firmware version 1.12, later on the upgrade to 1.25 was released.
 
Headphones used:
Final – Sonorus VI
Final – Heaven VII
Pro-Ject – Hear it One
 
other gear used:
Cambridge Audio – Go V2
Pro-Ject – Stereo Box S + Speaker Box 5
Self built laptop running OpenSUSE 13.1
 

 
Package and Accessories:
 
The box comes in a matte black cover, which already screams premium from every corner. After the cover is slid off, the main box comes out. Again, everything from Astell & Kern is designed to remind you that you don't have an everyday DAP in your hands, this is how high-end feels like. And on every removable content, even on the mSD slot covers, there's the logo of A&K so you don't forget who brought you this experience.
 



The opened box brings out the AK100 II. Here it is. It's lying there peaceful and waiting to be discovered.
Under it is the box with all the accessories. What you get is a gray leather case for the DAP, a protective film, a mSD card slot cover (one's already inside the slot), a micro USB cable for charging and data transfer, a warranty card and a quick start guide. The screen has a protective film pre-applied.
 






 
Content summery:
 
AK100 II
Gray protective case
micro USB cable
two mSD slot covers
protective film for the back
Warranty card
Quick Start guide
 
Build:
 
The AK100 II is completely made of aluminum, only the back is covered in clear plastic. You will definitely feel its weight of 170 grams in your hand.
The front face of the device is nearly completely used for the 3,3 inch AMOLED touchscreen. Which is readable without any problems, the screen brightness can be easily adjusted with a swipe down from the top. The player feels great in hand and its size is perfect for one hand navigation. I can reach every corner of the screen with my thumb and my index finger takes over the volume control.
 
On the left side of the AK's body are the three hardwarebuttons for play/pause, previous and next track. Also the mSD slot is found there.


On top there are two jacks. A regular mini jack for phone/optical out and a 2,5mm balanced out. Next to the balanced out jack there's the powerbutton. The only thing on the right side of the device is the volume control wheel, where you can set the volume in 150 steps.


 
On the bottom there's only the micro USB port for charging, data transfer and USB DAC function.

 
One thing that could use some work is the mSD port, it is really hard to insert and extract the card, since it's pretty deep in the device. I almost always used a second mSD card to get it in/out.
 
iriver really pulled the design. It is the best looking DAP I've seen so far. It's not bulky or unhandy, yet beautiful and unusual stylish and at some point I felt under dressed.
 
User Interface (UI):
 
The UI is based on Android, and definitely the best one on the market. Only Rockbox beats the AK's interface. It is designed to be very easy and intuitive. Every content is reachable with your thumb, which makes navigating very simple.
The AK100 II will let you search your songs by title, artist, album, genre or playlist. You can also search your database with the songtitle directly or sort your songs by quality (All, MQS, DSD). Or you can easily access your songs by folder view.
It features a wonderful playlistmanagement, where you can simply add artists, albums or single songs to the current playing songs. Or you can drop them into an existing playlist or create a new one.
The home button brings you back to the main screen with a short press.
With a swipe up or down over the cover art you can either play the next or previous song.
If you go through your library and swipe down the screen the UI will show a scrolling bar on the right side of the screen for you to go even faster. A wonderful feature for huge playlists and databases.
A swipe down from the top brings you all the quick settings you need. You can easily access the most important settings. Turn on/off wifi and bluetooth. Change from MTP connection to USB DAC function. Activate the equalizer, gapless, balanced and line out. Set the play mode and brightness. It also shows you the most recent and important notifications. In the upper right corner you can access the settingsmenu. If you long press WiFi, bluetooth or EQ you can move to the corresponding screen.
One thing that caught my eye was the equalizer. It's a ten band EQ, which features two presets, Pro (settings as recommended by professionals) and AKT5P (for the headphone with the same name, made by beyerdynamic), these can not be modified. But you can also add custom EQ curves by adjusting the frequencies of the 10 band EQ. I hardly use it, but when I do I create customs for my headphones instead of genres. That way I can fine tune my cans to the desired sound.
The top part of the screen is the notification bar, which shows you what's currently enabled, e.g. shuffle, Line Out, WiFi, bluetooth, battery percentage, time etc.
The only things missing in the firmware are replaygain and putting songs in queue, there is a feature, only sensible imo when playorder is not set to shuffle, to move songs around in the playlist.
Also there's only one bug in the software, the device never remembers the USB mode settings. I always had to set it back to DAC. Luckily the UI was well designed and the quick settings are accessed extremely easy.
 

                 UI with firmware 1.12                                                              UI with firmware 1.25
 

   Quicksettingsmenu open with a swipe down from the top                          Now playing screen
 
Changes of the new firmware (1.25, released August 18th) which should get reverted in my opinion:
- long pressing the home button brought you back to now playing before, disabled now.
- the ability to draw EQ curves for a fast and easy way to add custom settings
- home screen now takes up way too much space, the buttons were already very well designed in the previous firmwares.
- for faster scrolling the bar on the right side (in database) used to be an alphabet, to get you to a specific letter.
- USB DAC makes audio out of sync, very annoying!
 
 
Bluetooth streaming:
 
The AK100 II also supports bluetooth streaming to portable speakers or wireless headphones. It comes with bluetooth V 4.0 and no aptX support.
The bluetooth streaming option is recommended for any file format up to 48kHz, any higher resolution files may stutter. And I tested that too, it did.
I tried streaming different high-res (96-192 kHz) files to my Cambridge Audio GO V2 and all of them had hiccups. Everything below 48kHz was fine.
It will be a long way until bluetooth streaming will get close to the quality a wired connection offers in my opinion.
 
USB DAC:
 
At first I was a little worried that it won't work as USB DAC since I've read that a few Mac users had problems connecting the device with their computers. But all worries have stepped aside as soon as I tried it out myself.
I only use Linux machines, and never have I had any problems using the AK with either my laptop or my PC. Everything works out of the box (with pulseaudio en- and disabled).
Unfortunately the highest supported format is 24/96, so everything above that will get downsampled.
The new firmware also changed the DAC function, and not in a good way. When using the AK100 II as DAC and watching movies you'll definitely notice that it is out of sync! The audio is about half a second late, and this is not what you expect from a 1200€ device. VERY DISAPPOINTING!
 
@Limexx found a fix for Windows machines:
 
1. Right-click the speaker icon and click 'Playback devices'
2. Double-click the AK100ii
3. Go to advanced
4. Unclick exclusive mode
 
So far I couldn't find a global solution to this problem for Linux/Mac users.
If you're using VLC you can easily fix the synchronization by pressing J or K while the video is played, but the delay's still present with any other content (e.g. youtube videos)
 
Sound:
 
iriver does not want their players to be in the same boat with the others, that's why they call their DAPs “Mastering Quality Sound Portable Systems”, and that's what they are.
I have heard FiiO's new generation X5 because I also wrote a review for it. I was, and am, really impressed with the sound that comes out of it, but the AK is a whole different league. It makes the FiiO sound muffled and very analytical.
 
The AK100 II has a huge and super realistic soundstage with the best image I've experienced. It's unbelievably balanced and neutral. In fact it's the most neutral sound I've heard coming out of any device, desktop or portable. It has a great vivid body and a lot of air between the instruments. Its attack, decay, sustain and release are very impressive. It also has a very black background. Every frequency gets delivered fast, crisp and super precise with outstanding instrumental separation. This is how it's supposed to sound like, true mastering quality.
The firmware upgrade was very noticeable in sound. It made the device sound even cleaner, wider, more natural and precise.
 
The AK100 II makes any other DAP I've heard sound boring and blurry, and I don't know how to go back to the X5 now.
 
I tested the AK with three different headphones. Pro-Ject's Hear it One, and Final's Sonorus VI and Heaven VII.
 
The Hear it One has a wonderful soundstage for a closed back headphone, it sounded great, a little warm but over all very well defined. Highs are very sharp while mids come along very smooth, bass is overly present for my taste. Listening to Jazz recordings, especially Dave Brubeck's Time Out in DSD quality, with this headphone was the best combination for it. Trumpets, Snares and Basslines sound very natural and smooth.
 
The Heaven VII shows more detail and better soundstage, also more neutral and natural. The highs are this headphone's strongest point. You can almost feel the strings and triangles. Also the bass lines appear clearer and more lifelike.
 
The Sonorus VI are definitely the best headphones in this comparison. The soundstage grew again from the previous phones. Overall the sound is more vivid, precise, neutral, detailed and natural. This is the best setup in my home for the AK100 II. It also was my main combination in the time I had the AK. The sound showed astounding microdetail and instrument separation I can not compare it to anything I have heard so far.
 
I think to enjoy the AK's full potential you should listen to it with proper headphones, even though it brings out the most of the lower end cans, you will experience something amazing with better iems/headphones.
 
Conclusion:
 
The AK100 II is the whole package. You get incredibly beautiful design, the best user interface and addictive sound. But you have to pay a lot of money for that, if it's worth it is yours to decide.
The lag in DAC mode's a huge disappointment, I really hope Astell & Kern/iriver will fix this with the upcoming firmware, it worked perfect with the previous release.
 
Currently you can get it for $899 or €1199.
 
 
Final Words:
 
Again I would like to thank AudioTuning for providing me with a sample of the AK100 II for this review. It was an unbelievable experience.
With a heavy heart I have to send it back now.

If you have the chance to audition an Astell & Kern, do it, but remember, their sound might not let go of you.