or Connect
Head-Fi.org › Head Gear › Portable Source Components › Digital Audio (FLAC/MP3/etc) Players (DAPs) › Astell&Kern AK100II High Resolution Single DAC Audio Player

Astell&Kern AK100II High Resolution Single DAC Audio Player

100% Positive Reviews


Pros: The neutral and open sound signature of the AK100 II will grab your attention and never let go while you’re on the go.

Cons: Not cheap, no USB DAC functionality for Macs.

Astell & Kern AK100 II: Portable Pleasure


So I have a confession to make: I’m a DAP “noob”. I’ve basically been old school with my on-the-go Hi-Fi, using iDevices and a third party amp (HeadAmp Pico, RSA Audio Hornet, et cetera…) or even an Amp/DAC combo like the Beyerdynamic A200p. Then I tried the Astell & Kern AK100 II. While I’ve heard some lower priced DAPs, I’ve never felt the need to reach outside my iDevice/external amp setup. That is of course until I got to review the AK100 II.

Astell & Kern is a division of iRiver and based out of South Korea. The company offers three high end Digital Audio Players (DAP): the AK100 II, AK120 II and their flagship, the AK240. These are all serious “high-end” products. The AK100 II is the successor to the already popular and highly respected AK100. The updated verision utilizes a DAC chipset (CS4398) by Cirrus and a dedicated amplifier that outputs 2V in balanced mode and 1.7V in unbalanced mode. Though I would have liked to see a balanced adapter included with the player, one can still purchase the adapter separately.


I’ve run IEMs (Shure SE535s), portable headphones (beyerdynamic T51p and Sennheiser Momentum On-Ears), and full sized headphones (like the Fostex TH900s, Audeze LCD-Xs and Grado PS1000e’s) with the AK100 II. All cans were certainly driven with authority by this little unit. The AK100 II is also WiFi capable, so you can use the supplied MQS Streaming software to stream music off your home music server. This is a fantastic aspect of the player and it allows you to stream your entire the music from your main server to your Astell & Kern DAP – giving you access to your entire digital library. The setup is simple and the convenience is much appreciated. Another added bonus is the ability to update the firmware wirelessly.

In order to increase your storage space from the supplied 64Gb, the AK100 II has a microSD expansion port for an additional 128Gb of storage bringing the grand total to 192GB. That is plenty of music to take with you and should suit your portable needs nicely. The AK100 II also can be used as a USB DAC and take the music off your computer and feed it to your DAP directly. 


ak100__02The overall construction is solid! It’s made of a hairline and diamond cut finish for the aluminum body. While it’s not cheap, coming in at an MSRP of $899 USD, it does step up to the plate with fantastic build quality. The volume control knob is a stepped attenuator (something I really haven’t come across on portable DAPs) and each step is an impressive 0.5dB. So you will have the benefits of precise left and right SPL levels that a stepped attenuator offers with the added bonus of 0.5dB steps to get the listening levels exactly where you want them (as with an analog attenuator). It also comes with a handsome carrying case to protect the unit.

The touch screen and GUI (graphical user interface) is quite intuitive and easy to navigate through. It offers a clean and simple presentation and accessing the quick menu is as easy on my iPhone (just drag downwards from the top and you can access Wi-Fi, Bluetooth, EQ, SD card safety removal, among other things).

Navigation is also well executed as the layout is simple and straightforward so you can easily find your favorite artist, album or song. And going back to the home screen is as simple as pressing the “Home” button on the bottom of the unit. Astell & Kern has obviously put a lot of thought and care into this fantastic operating system and GUI that is not only intuitive, but provides you all the functionality you may need while never being difficult to operate.

The battery life on this little guy is impressive. I’ve used it continually at work with my Shure SE535 IEMs for a solid week and only needed to charge it at the end of the week. This is on par with my iPod Classic (160Gb) and is certainly more than enough to keep me happy. It is rated for up to 12 hours of playback before needing to be recharged.



I’ve literally thrown every codec that I have at the AK100 II: Lossy MP3s, lossless music, high resolution 96 and 192kbps files, FLAC and DSD have all worked flawlessly. I didn’t even need to setup separate folders for each file as it was just copy and paste onto the AK100 II and then just press play. It was literally that easy. I definitely appreciated this simplicity of operation.

Sonically, I would classify the AK100 II as a clean and spacious sounding DAP with excellent detail retrieval. I wouldn’t call this a warm sounding unit. Don’t get me wrong, the bass is certainly there, but if you’re looking for a slower bloom, (a coloration in my opinion) then you might want to look elsewhere. But listening to Metallica’s “Enter Sandman” from the Black Album, the rumble down low is more than satisfying with my Shure SE535s or Beyerdynamic T51p’s. They reach down to the lowest depths and offer a taught and quick bass that never lingers more than the recording calls out. However, I know some prefer a boomier bass with more bloom and if that’s what you’re after; then, I’d suggest you play with the EQ, which also works quite well and didn’t introduce distortions or artifacts during my trials. Accessing EQ was simple, just use the pull down feature to activate it and set the equalization to your preferences.

The one thing that initially struck me with the sound of this DAP is just how clean and open it sounds. The ability to render detail (and finer micro detail) is simply jaw dropping. I was mistakenly under the impression that one needed a desktop sized DAC / Amp to achieve this impressive level of detail rendering and sound staging ability, but it appears that the AK100 II is up to the task. There are always sacrifices one has to make with portability, that’s obvious due to plain physics, but with the AK100 II, I feel those sacrifices don’t have to be as large as I initially thought. Plus the ability to save up to a whopping 192Gb worth of data can mean you can also carry a good portion of your music with you and not have to only select the “Greatest Hits” albums in your collection as a compromise.

The treble extension of the AK100 II offers an airy and open presentation with outstanding shimmer and detail of the upper registers. As mentioned before, this is not a warm sounding DAP, but rather neutral and as such, the treble is not rolled off; however, it is neither strident, nor “bright”. When listening to Gustav Mahler’s Symphony No. 4, the flutes and sleigh bells sounded sublime with incredible detail that could compete with an impressive full sized rig. I couldn’t believe just how good both my SE535 IEMs and Audeze LCD-X full sized headphones sounded. The AK100 II was able to locate each instrument precisely in my mind’s eye with outstanding instrumental separation. The cast sound stage was both wide and deep. If I had to list the top item I was most impressed with this unit, it would be its ability to sound open, clean and offer top-notch imaging. I threw several other albums at it from Rush’s Moving Pictures, to Frank Sinatra’s Duets, to The Black Key’s El Camino, and it never once sounded closed-in or congested.


And the vocals are sublime. K.D. Lang’s Hymns of the 49th Parallel reminded me why she is one of my favorite female vocalists of all time. Listening to her sing Leonard Cohen’s “Hallelujah” or Ron Sexsmith’s “Fallen” was awe inspiring. The AK100 II kept up with this demanding recording and I can easily say that Lang has never sounded this good when on the go. Her voice was neither withdrawn nor pushed up front, but in almost perfect proportionality to the rest of the music. And thanks to the AK100 II’s ability to render an incredibly high amount of inner details, I was left imagining myself in the recording studio sitting right in front of her. I can only imagine how good the AK240 would portray this album considering how amazing it sounded with the AK100 II.

Overall, while not cheap by any means, I think the AK100 II offers outstanding value as it rivals some of the better and more costly desktop rigs (with a standalone DAC and amplifier) that I’ve heard. Throw in the fact that you can carry up to 192Gb of your high-resolution music with you and you can use this DAP as a standalone USB DAC with your PC, it’s a real winner for those who are looking for great sound on the go. The neutral and open sound signature of the AK100 II will grab your attention and never let go while you’re on the go.


Pros: Amazing sound, usability and design in a single package

Cons: Accepts “only” one Micro SD card

Whereas I am also an old school hard-core vinyl aficionado, I (luckily) jumped the digital high-res train early enough to nowadays be equipped with the most necessary hard- and software to be able to really enjoy that playground.


After the rise of CDs in the early 80s I started to examine the options with Sony’s SACD as soon as it became available on the consumer market. And to a certain degree I still use SACD. Namely the SACD plugin (…or “add-on” or whatever…) for foobar2000 to play DSD via my ifi micro iDSD.


Concerning portable high res, earlier I “played” around with the AK100 (MK 1, the one with the rather high output impedance), I own a FiiO X5 and I had a loaner X1 for testing. I also use the Onkyo high res App for iDevices, but I am not sure whether this really brings high res to the output, or whether it downsamples to easier processing 48kHz/16bit… I’d rather guess so since when I compare higher res flac with wav on my iPods I frankly cannot hear a difference that could not also be created just by using a different player software / algorithm.


Design (Hardware)


First thing I need to mention: The design. I am a design fetishist and this passion certainly is having a share in triggering my purchases. Well, in the case of the AK100II I have to say: Close to perfect!!!



The AK100 Mk1 simply didn’t have the proportions. Also the weight didn’t fulfil the expectations I had towards a high end player. Sure, lightweight can be an advantage for mobile usage, but my haptic senses were absolutely not satisfied holding it in my hands.


The FiiO X5 & X1 come along somehow too “martial”. Especially the X5 could be a kind of a 1990s military walkie talkie design study. Well, there will be those who appreciate that.


Back to Astell & Kern. Even within the actual AK product range the AK100II is my favorite design.


To me the AK120II has a too high forehead (if you know what I mean)...



...and the stealth design of the 240 is just too much for me. Whether good or not, it is simply not my piece of cake.



So lucky me, that the one I like most is also the most affordable one, which surely made a purchase decision easier.


By the way, until today I simply reject to upgrade from my iPhone4 since I prefer its design to the younger versions by far!

Here a comparison of size AK100II to iPhone4



The AK100II feels great to hold in my hand, also the weight is what I expect. The sharp edges, the brushed aluminium surface and the postmodernist volume-wheel protection feature adds just the right pinch of spice to an otherwise slightly too reduced formal language.


Also the touch screen is the right size and well readable.


One of my conclusions from the X1 / X5 comparison was “Maybe the X7 will have a larger touch screen? …and WIFI (…)

…and then the AK100II comes along and offers exactly this…


Design (Software / User Interface)


This leads us directly to the user interface. It is as nicely designed as the hardware.

Reduced to the minimum and necessary. Well readable. Self-explaining, just the way it makes it a joy to use it. This is actually one of the weak points of the FiiO X5. Harder to read, less comfortable to use and an issue with the volume buttons and skipping titles. All of that is by far better solved with the AK100II.


The “home button” integrated to the touchscreen is a very nice feature, and the volume knob a joy to use. It goes in 0.5dB steps. If you want to go faster you can also pull the spherical volume visualisation on the touchscreen for a convenient fast adjustment.





Anyhow, I actually preferred the rather hefty approach of the FiiO X5 compared to the AK100 Mk1. I also found the X5 more open and less coloured. But I have to admit that this might also have been owed to the fact that I had the AK100 Mk1 with the high output impedance and most of my cans are rather low in that aspect leading to a sub-optimal dampening factor. There was a Mk2 with a significantly lower output impedance but I never had the chance to hear that one, so now I have not the slightest idea how this (improved) AK100 Mk2 would stand against the FiiO X5 or against the latest AK100II.


But one thing is for sure, the sound of the AK100II plays in a different league compared to the X5; to be fair it is also in a different price-league. Who knows what the FiiO engineers would create with such budget given… but well, that’s another story then, maybe a X7…?


The first thing I recognized when auditing the AK100II was the openness, transparency and clarity of sound. It is so… “non-grainy” (…sorry, have no better word for that).

You might have guessed it, great detail, soundstage and separation of sound-sources are a direct result of such precision. I guess with this everything was expressed that is necessary to be said about the AK100II’s mid- and high-range.


What really surprised me was the bass, which is utmost precise and structured and as such goes perfectly well with mid- and high-range. But whats really great is the fact that it still has the substancial impact I expect.

I experienced with a lot of other equipment that precision of bass had to pay the price of lacking impact. Or the other way round, bass impact came together with a loss of contour. Not so with the AK100II. Here it just sounds right.


I just now listen to Symbion Project “Pawn To King 4” with the LCD-X. Wow, clear, fast & deep going along with the necessary impact and pressure.

Earlier today it was Philip Glass’ Akhnaten, Rush Moving Pictures and Thievery Corporation. All just as I like it.



Obviously, since the LCD-X is driven with ease, also the less demanding AH-D7100 and AH-D600 go very well with the AK100II, and my Monster Miles Davis Trumpet are plugged in anytime I use it mobile in the subway or whatsoever.


So I actually listened my digital music collection randomly up and down with the AK100II; and this I must say was a quite joyful trip...


The 7100 I do not use for travelling, the loss would be too high if lost…As such, for travels and hotel listening I will prefer the combination AK100 with AH-D600. Together with the short Denon cable for mobile usage this sounds simply fabulous!




I would call the overall sound signature “neutral”, but not the “dry” style of “neutral” which is in so many cases associated with the term, no, it is the natural aspect of neutrality. It simply sounds naturally neutral. Yes, that’s it!


Comparing the balanced and the un-balanced output with the SE535:

As expected the sound signature remains the same. Also power-wise I couldn't say that this makes a significant difference because the SE5535 obviously doesn't need a lot of it.


Still, the bass is now even slightly more structured and transparent (...I was surprised that a "more" was still possible...) and there is a hint of more open mids resulting in a marginally larger soundstage.



I didn’t try the streaming- nor the DAC function. I have great dedicated units for that, and I do not want to bother to connect it back to the main rig anytime after I used it mobile. So no use for me to really look into it.


So far from my side; a double thumbs up!


All I would have wished for is a slot for a second Micro SD card (so here X5 has a point; it can take two 128GB solid state drives)...




PS.: So what happens with my X5 now? It remains in my main rig as a digital High Res source, feeding the DAC there via coax cable… Here it is just perfect with its 256GB. As such I have a classical win-win situation :atsmile: 


PS: At the moment this is my most favorite portable combination: The AK100II with the AH-MM400:



More pictures here.


Pros: Great sound, Compact, Feature rich, great UI

Cons: Sync Software would be great

I recently got the AK 100 II after dabbling with a phone based stack.


Alternate setup:

    Samsung Galaxy S5

    FIIO E18

    + PowerAmp Pro (Cost: 2.99€) + iSyncr (Cost: 3.99€) + Stream to Media Devices, BubbleUPNP (Cost: 3.49€)


Sound Quality for this setup is GREAT. Love the E18 and its performance and great sound.



I had bought the E18 so I could combine good music and being on the go with 1 "device".

After a couple of weeks, I found that a phone based stack is a bit cumbersome and not very handy.


So, after snooping though the forums for ages, reading up on features, sound, etc I saw that Astell and Kern released the new AK100 II.

The AK100 II was announced with most of its primary parts as the AK240 has, but a single line (so no dual DAC and AMP and without the dedicated DSD processor)

It runs on a proprietary Android version, seems to have a nice UI.


As we do not have any shops in Belgium carrying them ... I decided and went for a bind purchase from a great shop in the UK (I live in Belgium).

(http://www.custom-cable.co.uk/) Within a few days my new AK100 II arrived, I unpacked carefully but in a hurry ... curious to see, hear what I had bought.


First Impressions

The package I got from the shop in the UK was a quite large cardboard brown box. On opening the box I found an nice AK branded black box. The AK packaging is a nice even black with only the AK logo on it.


[Some pictures]













The UI [User Interface] is a smooth, easy to use. It has been made for non expert users, easy, few buttons, sleek.


Once I put some music on it I finally got to the listening part .... and what a PLEASURE that was.

Very clear sound, silence is silence, my library with a mix of classical -70%-, trance -15%-, bagpipe and jazz came to light.

Most of the tracks are in FLAC, in different levels of quality (16/44 up to 24/192).


I immediately tried my different headsets, BeyerDynamic DT880, AKG K551, Sennheiser Momentum, all performed great. The AK even pushed the BeyerDynamic DT880 250 Ohm very nicely.

The sound stage on the AK100 II is wide, pure and light. Never boring or flat.


I asked a colleague at work (a 'real' audiophile) to give it a listen.

He was using his shure 215's (he is the 'room' type audiophile, the shures are for at work).

During his listening he immediately noticed the very pure and open sound, more spacious. His comparison was the exact same audio file on his iPod to my AK 100 II.

(file used was: Buena Vista Social Club - 1997 from iTunes)


He was truly astonished that only the device could already make this big of a difference.


The software on the device comes with a great EQ for those who need it. Just draw the EQ line on the screen and the software matches the line you drew.

Again, simple and easy to use.



The only thing I would suggest Astell & Kern to add would be a good Sync Software so users can easily select what they want to Sync with their very nice AK devices.

I'm sure a collaboration with a good maker is doable ... why not with MediaMonkey of FooBar2000 community?

It would make our lives so much more practical.


You can of course just copy the files with Windows, but that is not hand and it is not really manageable.

Having Sync list 1 for weekends, Sync List 2 for work, etc could be very nice.



Small note: It work also great a DAC on my PC's!!!   :-)



UPDATE [3-Jul-2014]: The AK100 II also works as DAC on my Samsung Galaxy S5, but via a OTG cable and not via simple micro-usb to micro-usb, it MUST be an OTG cable.

                                 Otherwise just Plug and play!!!




Well, that is it for me.


VERY, very happy with my new player!!!!


     - Compact

     - Great battery life (2 to 3 days at work, and you could add an external battery pack to recharge ...)

     - Great Sound with a wide sound stage

     - Great detail in the music

     - Excellent UI (bit slow with over 2400 songs + Album art)



With Kind regards,



A very happy customer.

Astell&Kern AK100II High Resolution Single DAC Audio Player

A New StandardA new standard for listening to music was proposed while developing the AK100. Astell & Kern recognized that certain aspects of the AK100 needed improvement during research and development for a successor. While considering how to improve the AK100, they realized that there was a difference between measured audio specifications and what they felt sounded good. After much deliberation, their development efforts were focused on making the AK100 2nd Generation "feel" right to their senses rather than mechanically boosting technical specs. The original AK100 was developed according to audio specification standards, but development of the next-generation AK100 was developed to the "New Standard" of how the music sounds. Astell & Kern presents "A New Standard in Listening to Music" with the AK100 2nd Generation.Single DAC and Balanced OutAlthough the dramatic depth in sound quality delivered by the Balanced Out was proven in their flagship model, Astell & Kern wondered if the same benefit could be gained by implementing the Balanced Out with a Single DAC. The newly designed demo board delivered the ear-pleasing sound quality that is needed. The value of a Balanced Out with a Single DAC is confirmed with every musical note. The AK100 2nd Generation provides a rich, warm sound experience through the re-tuned A-amp designed specifically for the CS4398 Single DAC.Unbalanced vs. Balanced OutputThe unbalanced method is the most commonly used basic method which

FeatureBody Material: Aluminum Display: 3.31" WVGA (480 x 800) AMOLED Touchscreen Supported Audio Formats: WAV, FLAC, WMA, MP3, OGG, APE(Normal, High, Fast), AAC, ALAC, AIFF, DFF, DSF Sample rate: FLAC, WAV, ALAC, AIFF: 8kHz - 192kHz (8/16/24bits per Sample)/ DSD: DSD64 (1bit 2.8MHz), Stereo / DSD128 (1bit 5.6MHz), Stereo Output Level: Unbalance 2.0Vrms / Balance 1.7Vrms (Condition No Load)
TitleAstell&Kern AK100II High Resolution Single DAC Audio Player (Smoky Blue))
Item Weight0.88 pounds
Package Height2.4 inches
Package Length8.1 inches
Package Weight1.2 pounds
Package Width4.4 inches
ProductGroupNetwork Media Player
UPCList - UPCListElement821566014177
Model Name/TypeMPNEAN/UPC
Head-Fi.org › Head Gear › Portable Source Components › Digital Audio (FLAC/MP3/etc) Players (DAPs) › Astell&Kern AK100II High Resolution Single DAC Audio Player