Astell&Kern bring portable audio back to earth with AK Jr.


Idealists – they demand the best sound at any price. It’s an approach that invariably results in air strikes to the bank account. Astell&Kern launched their first digital audio player in 2013. The AK100 sold for US$699 and it impressed almost everyone that heard it. I reviewed it here. The general consensus was ‘good…but not cheap’.

More pragmatic users (like myself) were delighted that the AK100 easily bested the sound of their smartphone and iPod but our idealists were predictably tougher nuts to crack. In the months following the AK100’s launch, forum chatter and comments sections gathered pace to form a two-pronged attack: that side-mounted volume rotary – so exposed! Never mind that the bar to which the pot was attached traversed the entire width of the unit’s internals, it looked like one false move would decapitate it. And that output impedance: 22 Ohms! Quelle horreur! Never mind that plenty of headphones would pair just fine with this newcomer.

Astell&Kern did what any sensible business would do: they took the idealists’ desire for perfection (read: never happy) all the way to the bank. The AK120 arrived (review here) with a casework extrusion designed to shield the volume pot and a lower output impedance: 3 Ohms. It sold for US$1299. Then came a MK2 AK100 (US$799) with lower output impedance. The AK120 outsold the AK100 three to one at a time when Astell&Kern were still finding their way through a category they would ultimately come to re/define.

A year later came radically overhauled second-generation versions of the AK100 and AK120: taller, heavier, and shinier. Out went the Linux OS and Wolfson DAC chips of yore. In came Android and Cirrus Logic as well as an improved headphone output stage, 2.5mm TRRS balanced socket, a larger touchscreen and Wifi streaming. If you wanted in, the AK100 II would set you back US$899, the AK 120 II US$1699 (reviewed here).


Then came the unit that would really get summit-fi-ers salivating: the AK240. The market appeal didn’t just lie in the Escher-esque chassis or an ability to decode DSD natively. At US$2400, the AK240 is an out-and-out luxury item to be paraded in front of friends. Exclusivity through pricing and premium features, the AK240 currently outsells every other model in the range.

At Munich High-End this year we saw Astell&Kern inflate the high end DAP bubble further still. To get into the AK380 game you’ll need thirty-five hundred of your finest Earth dollars. Youch! Heaven for idealists with deep pockets but for pragmatists, wtf?!

Panic not. Astell&Kern’s play from left field just prior to Munich reminds us that they haven’t forsaken mortals with considerably less disposable cash: the AK Jr. (US$499) packs an almighty wallop for such a tiny device and it could be the South Korean company’s finest offering so far.

To see why, we need to re-calibrate perspective.

The AK Jr.’s slender physique is Astell&Kern gone Lite n Easy. You don’t need a spec sheet to tell you this is their thinnest and lightest player to date but for those readers yet to go hands on: the 8.99mm thickness at the upward-facing single-ended 3.5mm headphone connector tapers down to 6.99m at the unit’s base. The volume pot’s relocation to Junior’s underbelly is an ingenious move.

On the scales the AK Jr. weighs in at 93g – almost half that of the AK100 II. The upshot is Junior can ride in a shirt breast pocket without issue. You can’t say that about the second-generation AK120/AK100 and (especially not) the AK240. You can’t say that about the now discontinued first generation models either. You can’t even say that about the 130g Pono Player.


Matters of aesthetics are more subjective so let’s not make it about you or me. Instead, ask yourself which DAP has the greater mass market appeal: the AK Jr.’s sleek industrial styling and its 7.9cm touchscreen or the Pono Player’s toblerone form factor and its 6.4cm touchscreen?

Moreover, convincing your average smartphone user that a ~$500 DAP is worth the moulah means a touchscreen is a must have. Rival models coming to market that don’t meet this modern day screen standard face harder yards. The AK Jr.’s screen resolution doesn’t compete with an iPhone – you can see that from just looking at it. Junior looks quite a bit more agricultural compared to the Cupertino device but it gets the job done. The layout of the AK Jr’s interface is Astell&Kern’s most organised and intuitive to date.

If, like me, you don’t dig having to use Android File Transfer app to get tunes from the OS X desktop to the any of Astell&Kern’s other models then you’ll be pleased to learn that with a Linux O/S in play on the AK Jr. we note a return to drag and drop file loading. Rejoice!

Linux also means no Wifi connectivity. Absent too is the 2.5mm TRRS balanced output socket so beloved by high end users. Pragmatists won’t see an issue with either feature set omission. You can’t everything for US$499.

Output impedance is a respectable 2 Ohms – a full 20 Ohms lower than the original AK100. The AK Jr. should see most users right with all but the lowest impedance measuring IEMs. During my listening sessions, I witnessed zero evidence of bumps or dips in the AK Jr.s frequency response with either the Campfire Audio Orion or the A&K-collaborating Jerry Harvey Layla. The same clean, exacting and oddity-free audio spilled from a pair of custom fit Ultimate Ears UE 7 Pro, which sound somewhat off when driven by a Pono Player.


With full-sized portable ‘phones, the AK Jr. sounded terrific with the OPPO PM-3. Perhaps a little dry at times but certainly nothing worth kicking up a stink about.

Paydirt was struck with Master&Dynamic’s MH40 (reviewed here) whose inherent fat, chunky qualities play the perfect counterbalance to Junior’s clean(er), lean(er) presentation; which also matches well with the soup-thick midrange of the Cardas EM5813 Model 1 and affection lent to transient delivery by the semi-open AudioQuest NightHawk. Not three years ago such portable audio satisfaction would have been unthinkable. That the MH40 also step up with similarly impressive ‘executive’ styling to the Astell&Kern player is a bonus.

Moving from outward beauty to inner workings, the AK Jr. sees Astell&Kern return to Wolfson decoder silicon – this new DAP uses the same WM8740 chip as found in the original AK100/120 and handles up to 24bit/192kHz PCM and DSD (via a priori PCM conversion). However, the AK Jr. doesn’t coat transient nuance with as much warmth and softness as the original AK100/120; if you enjoy the latter’s sound, stick with it. It’s also not as full in the bottom end or as rich sounding as the AK120 II. The latter difference is mostly attributable to the AK Jr.’s leaner mid-bass. Think of the difference between your average Pinot Noir and Cabernet Sauvignon and you’ll know where I’m coming from.


The AK Jr. comes on zippy and clean, their most transient-energetic voicing to date. It sounds closest to the Sony NWZ-ZX1 (reviewed here and here), captivating the mind before intoxicating the heart. The Ak Jr’s top end doesn’t offer the golden-hued, honeyed-dipped vibe of the Pono Player (reviewed here).

For summit-fi-ers already won over by the sound of higher-end Astell&Kern models the AK Jr. might provide the necessary brand-matched context from which to re-asses their favourite player’s inherent portability; especially those on the cusp of strapping an outboard amplifier to an AK240! Either enjoy it for what it is/does or consider selling up and downsizing to the AK Jr. to which appending a third-party amplifier makes more financial and form-factor sense.

What of the pragmatist looking up the hill from his smartphone for the first time? Ascending to hill brow and looking downward, the AK Jr. sounds better than each of the mass-market devices I own. I hear better separation, clarity and frequency extension than the iPad 2, Google Nexus 5, Samsung Galaxy S5 and iPod Touch 5G. No contest. I think it’s a safe bet that if you’re prepared to offshore music playback to a separate DAP and carry a second device then you’ll be rewarded with a far more satisfying music experience. The AK Jr.’s ectomorphic body type means you won’t be hauling too much in the way of extra ass.

AK Jr. amelioration doesn’t just apply to street life. With this portable also deployable as a USB DAC it’s worth noting that it dumps on your average PC’s headphone output from quite the height, thus exposing the computer’s on-board sound card for the fifty-cent part that it is.


At least, that’s the theory. I’ve used the AK Jr. on a daily basis since the Munich High-End Show. It takes time to get to know a product, what it can and can’t do and whilst concluding this review I uncovered a kink in the AK Jr.’s otherwise faultless value proposition. Underpowered USB ports found on some host computers don’t like the miniature AK as a USB DAC (mine’s running firmware v1.02).

On a 2013 Macbook Air, OS X announces the Jr. as an available USB sound device in the preference panel but upon selection no sound spills forth – a result echoed by this Head-fi user.

The Microsoft Surface Pro 3 presents with the same issue: device recognised by the host OS but no sound. The Linux-running Antipodes DX doesn’t see the device at all. Instead the AK Jr.’s own OS locks up, necessitating a device reboot. A compromise to be worn square on the chin by pragmatists (for now at least).

Let’s hope Astell&Kern can sort this quickly because the headline written by the AK Jr. for newcomers contemplating their first DAP is not to be missed: it’ll sound way better than your existing smartphone and compatible computer. If you’ve already dropped cash on a nice pair of headphones and are contemplating “What’s next?” the Astell&Kern AK Jr. will bring them to life at home, on public transport and at work.

Further information: Astell&Kern

Written by John H. Darko

John lives in the NOW + HERE = NOWHERE. He derives an income from the ad revenues of DAR. John is also an occasional staff writer for Stereophile, 6moons and TONEAudio.

Twitter: DarkoAudio
Instagram: DarkoAudio
Facebook: DAR


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  1. If I was contemplating moving from my Pono to this, is the experience and sound of the AK worth moving to it from the PONO?

    • The UI and form factor, absolutely. On sound quality the Pono still offers more filligreed top end than the AK Jr.

      • so it falls down on treble extension. how is it for detail overall and sound stage in comparison to pono?

        • Nope – it’s more the quality of the treble than its extension. I thought ‘honeyed’ encapsulated what I meant by that? Alas, time didn’t permit a more thorough side by side with the Pono player.

          • it would be an interesting comparison, honeyed is an interesting description but Im not sure in audio terms what it actually means. I think I am also going to look at the ak100 2 as well before I make a decision if I stay Pono or upgrade.

          • Think of a spoon. That’s the AK Jr.. Now think of a spoon that’s been dipped in jar of honey. That’s Pono. It’s subtly more ‘golden’ and ‘sweeter’ (but not overly so).

  2. So if it’s a big jump up from my phone as a DAP, what would be the relative merits of adding a DAC/amp of a similar value, given that either way I need to carry my phone plus a second device?

    • First thing you gotta think about is how you’ll attach the DAC/amp to the phone. Physically that means screen-obscuring rubber bands. Digitally it means an unsightly cable loop from Apple CCK or Android USB OTG. With cable loop at the bottom, how do you drop the combo into your pocket without crushing the 3.5mm headphone jack at the other end?

      • “You can’t(have) everything for US$499”

        Well the Pono player has almost everything for $399 and it’s been available since last year. So $500 isn’t a lot of money? All of these players including Pono are made in Asia. I’d think they should be cheaper to make than a smartphone. So plenty of profit margin. The way I see it prices should be getting even lower with more features. Looking back, old hard drive based ipods seem like a bargain compared to todays hi-res players.

        • Yup, Pono is $100 cheaper. And it shows in its casework, buttons and ‘controversial’ Toblerone stlying. Ditto its interface – rudimentary but it gets the job done. Agreed, not as slick as Apple. If the Pono Player didn’t sound as good as it does I’d have moved mine on by now.

          • The point I was trying to make is that Apple was doing this 12 years ago with a better interface than all of these new DAPs. The difference is the hi-res circuitry. And that doesn’t really cost that much. But because it’s “High End” the price has to be jacked up. And $500 is now considered a bargain?

          • I’m not saying $500 is a bargain. I’m saying that Astell&Kern’s push for increasingly expensive models has served to recontextualise the Jr. as ‘cheap’/’affordable’ (for some).

  3. Compared to the SQ between the iPhone 6+ and other DAPs like Fiio X5 and its coming up second generation what is your suggestion to get?

    • The AK Jr. will best the iPhone6+ for sound – of that I’m confident. Not having heard the Fiio, I don’t know it would fare in a similar standoff. However, your tolerance for in-pocket bulk also comes into play when comparing the Jr. and the X5. Also – does the Fiio have a TOUCHscreen?

  4. Hi John. Different physical decisions I know, but interested in your view as to how the sound quality might compare to an iphone 6 and an Oppo Ha2 ?


    • The HA-2 is long gone I’m afraid but if you’re prepared to trust my audio memory I’d say it’ll provide a bigger, ballsier, better-separated sound than the AK Jr.

  5. Great pick-up on the USB issue John. Scanning the forums finds similar tales of woe about some USB DVD burners not being properly powered by (in my instance) Surface Pro 3. One of the hidden costs of lighter laptops …

  6. Based on the affordable price level, your review and the cool styling A&K have just gained another customer. If marketed correctly this should sell very well indeed but hopefully the software bugs will be sorted very very quickly as this is a serious problem with the latest batch of new tech like the Aries, brilliant sound and frustrating software which will put a lot of people off.

  7. Darko,

    How do you think these higher end DAP’s from Astell & Kern stack up against iOS units with offboard conversion & amping? Strictly Sound quality wise? I’m more inclined to stow portable stacks in a bag than worry about pocketability. Being able to carry a desktop worthy rig to and from work is awful attractive.

    I’ve been trying to convince myself of the merits of AKxxx units but keep falling back on their lack of power for top shelf phones (LCD2, HD800, T1). Also is the 1.9volts out of the headphone socket friendly with downstream amping? I wasn’t sure if volume at 100 induces clipping or distortion.

    • On sound alone, I tend to prefer AK’s and the like when paired with outboard an amplifiers / DAC. The Chord Hugo and ALO International+ are two personal favs. As a rule, you get a weightier sound with more detail resolve as well a compatibility with a broader range of ‘phones (which for the solo AK player is comparatively narrow).

  8. Is Astell and Kern’s intent for people to use the 3.5mm headphone out as a line out as well?That’s a pretty commonplace output option that appears to be lacking on the Jr, AK100ii and AK120ii. They have optical out, 2.5mm balanced out (I assume for headphones as most portable amps don’t have balanced inputs) and 3.5mm headphone output, but none specifically lists an analog line out.

    Is there a setting in the UI to turn the 3.5mm into a line out? (That is how the Fiio units do it). Just thinking I’d rather use the inbuilt decoder and connect an amp when needs be but wasn’t sure if optical is the only way to tap the signal.

    • Yup – in the AK100/AK120 II’s system config there’s a setting for specifying line out on the 3.5mm socket. Same in the AK Jr – I just checked. Is this not covered in the manual?

  9. Sorry for the banal question John. I won’t bother you with any more Astell & Kern technical support questions. But thank you for answering all the same.

    The manual is not available and the specs posted on their website aren’t clear. The lack of any mention of a fixed line level output had me thinking I’d be bi-amping the signal if I connected it to a portable amp.
    I’ve got $500 +/- to spend on either an iFi iDSD to use with my deactivated iPhone or upgrade my source and buy one of these ‘on trend’ mid level DAPs that I can pair with my portable amp (an ALO The National).

    Knowing that the AKJr. has analog line out, sends it to the top of my DAP list.
    Only other DAP contender is…. ugh… pono. I dislike Pono because of the Bull$#!+ campaign but when you boil it down Pono is really an Ayre Acoustics portable. Not easily swept aside in that context.

    Anyway, thank you for the clarification.

  10. RE: Out went Linux OS and in came Android
    Technically, Android is still a Linux OS, albeit a highly bastardized (and less secure) version of it. Still runs the Linux kernel.

    RE: Touchscreens on DAPs
    Actually, I’m not so sure a touchscreen is a must-have for a DAP . In this day and age, where everyone and their dog carries a somewhatsmartphone, I think it’d be great to use the phone as a bluetooth remote-control of sorts. No audio streaming, just playback/playlist control and album art with an app. It’s been said that screens sitting close to DAC circuitry can cause some sort of SQ degradation. If that’s true wouldn’t it be better to leave the visual duties to your phone and just let the DAP worry about audio? Would also be great for the DAP’s battery life, me thinks.

    RE: Astell & Kern
    Seriously, has anyone ever met the actual Mr. Astell or Mr. Kern? Or are their real names just Mr. Jung and Mr. Hyeong?

    RE: Your review
    Excellent, as always, Mr. Darko. Much thanks for taking the time.

    • Touchscreen inclusion will always divide opinion. However, to the newcomer looking at the AK Jr., what’s more likely to be on his/her mind: convenience of touchscreen navigation or its possible SQ-degradation? The idea of using the phone at BT remote appeals; conceptually that sits somewhere between dedicated DAP and hooking a smartphone’s USB output into a third-party (bricked) DAC/amplifier.

    • I dare say the name has been plucked out of thin air in an attempt to attach some kind of ol’ world quality and cachet to the devices. It’s cynical marketing essentially.
      Think ‘Turnbull & Asser’ (shirts), ‘Poulsen & Skone’ (footware)

  11. Great review, John.
    I am considering replacing my original 120 because of software issues. How do you get a playlist into Jr? 120 requires using iRiver for playlists and iRiver does not recognises network drives or mapped network drives. Can you play randomly across an SD card? 120 will not play randomly across folders on the same storage, which is organised into folders Artist (not album artist) – Album.
    This is why I am looking for a replacement! Thank you.

  12. John.
    How do you load playlists onto the JR? My 120 only supports playlists through using iRiver software, which doe snot accept network drives or mapped network drives.

    • I’m the wrong person to ask as I don’t use ’em. I’m a folder structure browser.

  13. As a proud PONO owner, it is interesting to note that the new A&K doesn’t trump it, considering I’ve tested my PONO against the more expensive A&K 120’s and 240s and the A&K just sounds cleaner, more spacious and detailed…

    I’m suprised why the new cheaper SOny Walkman’s aren’t getting much love..I have an A15, and the sound differences between the PONO and Walkman are ever so slight with headphones, although this becomes more apparen;t when plugging into an amp.

    • I’m keen to hear the ZX-2 but I dunno, the smaller ones don’t excite as much. Maybe I should take a second look.

  14. I’m ready to ditch my ipod classic. It distorts all my WAV files and even mp3 files I purchased from Apple. I am interested in the AKJr and the Fiio X5 II. The two devices seem ripe for a head to head match, but no one on the internet has compared the two. Since I enjoyed your AKjr review, I’m begging you to compare it to the X5II. And if you think there is a better sounding player in the sub $500 market, please add it to the list.

    • Under $500, I’d still prefer the Pono Player for more types of music with a broader range of accompanying headphones over everything else that I’ve heard.

  15. The DAC issue you mentioned is related to a will known USB 3 versus USB 2. Using my 2010 Macbook Pro the DAC functions seamlessly with the USB2 ports. I also have it running on my 2015 Macbook Pro off of a USB3 port. If you search through the Head-fi AK240 threads will find the settings you need to set on the Mac’s with USB3 ports.