iRiver Astell and Kern AK100 Review

If premium sound is your guiding priority, and you have the cash, this digital music player may be worth taking a chance on, quirks and all - just don’t expect it to behave like a new iPhone.
If premium sound is your guiding priority, and you have the cash, this digital music player may be worth taking a chance on, quirks and all - just don’t expect it to behave like a new iPhone.
If premium sound is your guiding priority, and you have the cash, this digital music player may be worth taking a chance on, quirks and all - just don’t expect it to behave like a new iPhone.


  • Stunning sound quality
  • Extensive file versatility
  • Premium grade components


  • Slightly sluggish UI
  • Some quirks in function
  • Expensive

DT Editors' Rating

Sometimes to fight a giant, you have to think small. Just ask iriver. When the South Korea-based audio company created its portable, high-resolution music player, the Astell and Kern AK 100, it had no intention of taking on industry titans like Apple directly. Instead, iriver set its sights on that slim but tenacious segment of audiophiles who scoff at the average MP3 player. Its new device is loaded with quality components, and has the ability to play almost any music codec, including 24bit/192kHz high-resolution FLAC files. 

We first got our hands on the AK100 at CES 2013, and were truly blown away by its sound quality. Its unique ability to make studio master-quality audio truly portable makes it a music lover’s dream, and unrivaled in the portable audio market. Unfortunately, at just under $700, its price is also unrivaled. After our first encounter, we found ourselves wondering: Is any music player worth that kind of money? With that in mind, we sat down with the device for a much more thorough investigation.

Out of the box

The AK100 comes in a black cardboard box with the Astell and Kern logo monogrammed in shiny script on the cover. Inside the box we found the AK100 safely nestled in hard foam. At the onset, the device seems a bit retro, reminiscent of first-generation iPods and Zunes (remember Zunes?), but its stout weight and metallic construction give it a premium feel that outclasses early iPods by a large margin.

The AK100’s black exterior is decked out in brushed aluminum with an all-glass backplate. The high-quality construction contrasts with its boxy frame, putting it somewhere between posh and clunky. Perhaps this player’s oddest and most distinguishing feature, however, is its volume knob, which protrudes rather overtly from the player’s top right side like a tiny fishing reel.

Beneath the device, we found a compartment housing a small canvas case, a quick start instruction guide, and a USB to mini-USB cable.

Features and design

Lining the AK100’s left side are three buttons which control pause/play, track advancement and reverse. Along the top we found a hybrid headphone/digital optical output, an optical input, and a long power button fashioned in the style of Apple devices. Along the bottom of the device is a micro USB port, and a small door which opens to reveal two micro-SD card slots which can be used to supplement the AK100’s built-in 32 GB storage to a total of 96GB 

The unit’s LCD screen is touch-sensitive, which we found made user interface navigation relatively easy. Unfortunately, the AK100’s software feels sluggish compared to modern smartphones like the iPhone 5. 

iRiver Astell and Kern AK100 Review top ports

Under the hood, the AK100 packs its most potent weapon, the Wolfson WM8740 DAC – a top-level digital-to-analog converter (DAC). Other internal features include a high-quality headphone amp, a digital EQ with 5-band control, and Bluetooth wireless capability.

The player also boasts a battery capable of supporting a 16-hour runtime, measured with the LCD turned off, of course. With the screen turn on, we found that number decreased significantly. 

The Good

Audio performance

We paired the AK100 with Aiaiai TMA-1 Studio headphones and loaded it with a variety of different types of music files in various states of quality and codecs. Since iriver recently released a firmware update for the AK100 that enables it to play Apple-specific music files such as AAC, AIFF, and ALAC files, we included a few of those, along with WAV and MP3 files so that we could make direct comparisons between the AK100 and iPhone 5’s performance with identical file types.

The real stars of this audiophile show, though, are the high-definition FLAC files which Apple devices are incapable of playing. These ultra-definition digital audio files are said to be dead ringers for the studio master recordings they come from. Pre-loaded on our AK100 review sample was a 96kHz/24-bit master recording of Pink Floyd’s The Dark Side of the Moon. Since we’ve heard the album enough times to burn through the record, we figured that was as good a place to start as any. 

We could go on for pages about our experience, but in the interest of brevity, we’ll try to be succinct. In a nutshell, bouncing between MP3s on our iPhone to the HD files on the AK100 was sort of like Dorothy’s transition from her black-and-white Kansas farmhouse to the vibrant Technicolor pallet of Oz. Every instrument on Dark Side was rendered with almost jazz-like timbre and sensitivity, creating a transformative experience that combined all the dynamic and emotional resonance of a vinyl record with the immaculate clarity of digital sound.

iRiver Astell and Kern AK100 Review card slots

We experienced similarly stunning moments listening to high-resolution versions of Beck’s Sea Change, and vocal-centric tracks from Rebecca Pidgeon and Diana Krall. The intimacy of the ladies’ voices was so clean and clear, we felt like they were whispering in our ears.

We then put the AK100 into a cage match with our iPhone 5 by comparing each device’s reproduction of the same file. We ripped a CD copy of Bob Dylan’s Blood on the Tracks into Apple’s lossless ALAC format. Since we used a CD as the music source, we didn’t expect to experience the same “come to Jesus” moment we got when listening to FLAC files, but we did expect this test to reveal conclusively just how superior the AK100’s innards were to the iPhone 5’s.

Take a wild guess at which device won. There was no doubt the sound quality was superior from the AK100. All of the track’s instruments were presented with more depth, space, and clarity. In fact, Dylan’s voice came off as thin and weak on the iPhone. It was no contest, really.


Though its rather flimsy feel had us skeptical at first, we ended up enjoying the tight tolerance provided by the AK100’s volume control. The dial moves in half-step increments from 0-75 providing control at the micro level. It provides great precision, but if you find it to be too slow for your liking, a touch-screen option appears any time the volume is adjusted. 

iRiver Astell and Kern AK100 Review volume button

Another nifty level of control comes by way of the AK100’s easy content management. Unlike Apple products, all content can be moved on and off the AK100 like a hard drive, no proprietary software required.

The Bad


The AK100 does bear some bothersome quirks. First, we noticed what seemed like an unusually long gap (about 2 seconds or so) between songs, which we found especially annoying on concept albums. We contacted iriver about this issue and were told gap is the result of the device buffering the enormous FLAC files. However, we also noticed a slight gap on CD quality WAV files, which our iPhone had no trouble playing back to back with no gap.

Slow and scary

The AK100 tends to be sluggish in other areas as well. Every time you disconnect it from a computer, it takes around three minutes for it to categorize the song list, whether you’ve added music or not. And on three different occasions when we did load new songs, the AK100 gave us a nice jolt of fear when it informed us there was no music on the device! The problem was fixed by reconnecting the player to a computer, but we think these sorts of issues ought to have been addressed in a $700 device.


Our final complaint has to do with content – or the lack of it, rather. Though there are many albums available on irivers’ partner site, HD Tracks, we found plenty of huge holes. We realize that HD files can only be obtained if artists and labels are willing to surrender master tapes, but this lack of HD content will be an obstruction to adoption. HD Tracks also forces you to buy full albums – you can’t just pick up a track or two. This may be part and parcel of the content deals HD Tracks has struck, but we’re not convinced a crowd used to iTunes will respond warmly to this restriction 

iRiver Astell and Kern AK100 Review screen

On the bright side, now that Apple codecs are readable by the AK100, you’ll be able to listen to almost anything through the device’s premium components and enjoy superior sound.


There’s no question that the AK100 sounds absolutely incredible. We were most impressed by its performance when playing back high-resolution tracks, but we also enjoyed the improvement of other formats through the player’s premium components. As for general function, we were less moved. For $700, we expected the AK100 to run like a Swiss watch, and that just didn’t happen.

The bottom line is this: The AK100 is a first-effort HD player from iriver, and it feels like one. If premium sound is your guiding priority, and you have the cash, this digital music player may be worth taking a chance on, quirks and all. Just don’t expect it to behave like a new iPhone. Still, the fact that you can now put a shelves-worth of premium audio components in your pocket is pretty impressive, and we must admit: We wish we owned one.


  • Stunning sound quality
  • Extensive file versatility
  • Premium grade components


  • Slightly sluggish UI
  • Some quirks in function
  • Expensive
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