When Astell&Kern brought out its AK240 Portable High Fidelity Sound system (£2,199) about two years ago, many of us assumed the firm has pushed the sonic and price limits of the high-end portable player genre as far as they could go, but as it turns out we were wrong. Enter the firm’s spectacular new all singing, all dancing, and all-conquering flagship model, the AK380 (£2,999), which in some respects takes up where the AK240 leaves off.
One point we should stress from the outset is that the AK380 is not purely a single purpose audio player. Instead, think of the AK380 as the platform for an expandable, multi-faceted digital audio playback system comprised of the AK380 plus any of several optional, dedicated accessories Astell&Kern has in the works.
Among these upcoming accessories will be the AK380 Cradle, which not only provides the expected USB data transfer and charging capabilities, but also incorporates a stereo balanced analogue output via a pair of three-pin XLR-type connectors, thus inviting owners to use their AK380s as the primary DACs in their full-sized audio systems, without compromising portability. The next planned accessory will be the detachable AK380 Amp said to increase the power output and of the AK380 for purposes of driving power hungry headphones — especially “high-impedance professional headphones.” Last but not least, the firm also plans to offer a compact, desktop AK380 CD-Ripper, which is a handsome little CD-ROM drive that can rip CDs directly to the AK380’s built-in memory.
As you might expect, all three of these accessories are beautifully made and precisely matched to complement the distinctive design motif of the AK380. As of press time, however, Astell&Kern had not yet announced production release dates or final prices for the accessories (though having seen and tried them at recent trade shows, we can vouch for the fact that they look great and appear to work well). Stay tuned, and watch for further announcements from Astell&Kern.
Like most of Astell&Kern’s products to date, the AK380 features an angular and strikingly beautiful industrial design—one that perhaps answers the question, “What sort of digital audio player might M.C. Escher have designed?” I say this because the casework of the AK380, which is fashioned from aircraft-grade Duralumin finished in a tasteful matt bronze colour, presents a challenging optical puzzle of sorts. When you first hold the player in your hand, the illusion is that the unit’s 100mm touch screen deliberately has been rotated a couple of degrees out of true in a clockwise direction, which seems a peculiar (though not unattractive) visual detail. However, after some study, it becomes apparent that the screen is in fact perfectly true to the top and bottom edges of the player, but that the left and right hand edges of the case are skewed a handful of degrees past the perpendicular in a counter clockwise direction. This is precisely the sort of clever, whimsical, and thought-provoking design that has made A&K players so appealing to audiophiles and other style-conscious consumers over time.
Controls for the player are elegantly simple. On the left side of the case are three push-buttons supporting ‘Previous/Rewind’, ‘Play/Pause’, and ‘Next/Fast-Forward’ functions. On the right, one finds a neatly recessed, knurled thumb wheel-type volume control knob, plus a small slot where users can install an optional microSD card (with up to 128GB capacity), if desired, to supplement the AK380’s standard 256GB of internal storage.
On the player’s top edge there is a rectangular power switch that also doubles as a ‘Screen On/Off’ control. There are also two audio output ports up top: a combination Earphone/Optical output port (via a 3.5mm mini-jack), plus a Balanced Audio output port (via a 2.5mm, 4-connector jack). The rest of the AK380’s control functions are for the most part handled by the unit’s WVGA touch screen and its associated control menus, which I found reasonably intuitive to use. Completing the picture is a pressure-sensitive, metal capacitive ‘Home’ menu touch switch embedded in the lower centre surfaces of the metal casework.
On the bottom of the AK380 one finds a Micro USB port that allows digital audio files to be transferred to the AK380’s built-in memory and that also enables the unit to serve as a ‘slave’ DAC/amp that can play files from USB-attached PCs, Macs, or music servers. There are also four recessed connector contacts that provide ‘Expansion Unit Balanced Outputs’, which are presumably reserved for use with the aforementioned AK380’s upcoming, clip-on accessories.
The rear plate of the AK380 features an inset carbon-fibre back panel, plus a shallow, knurled-edge thumbscrew that serve to protect an inset threaded socket in the back panel where various AK380 accessories will lock on to the case of the main player.
The AK380 arrives with a useful and tasteful set of accessories including a Micro-USB cable, a microSD card slot cover, a form-fitted brown leather case, a set of protective film covers for the unit’s front and back panels, and the obligatory Quick Start Guide and associated Warranty Cards. Astell&Kern has also prepared an in-depth, 55-page Instruction Book/User Guide for the AK380, available online, which is pretty much required reading for those looking to take full advantage of the player’s extensive and multi-faceted capabilities.
While there are many similarities between the AK380 and the AK240 that preceded it, there are also several noteworthy differences. In particular, Astell&Kern emphasizes that, in contrast to the AK240, “Every bit of the AK380 was designed for Pro-Audio in mind.” With this objective in mind, the AK380 uses dual AKM AK4490 DACs, whereas the AK240 uses dual Cirrus Logic CS4398 DACs. Both players support native decoding for DSD64/DSD128 files, which many audiophiles consider a ‘musthave’ feature, and both provide bit-for-bit decoding for high-resolution PCM files. However, the AK380 ups the ante with bit-for-bit decoding, supporting PCM files all the way up to 32-bit/384kHz resolutions, where the upper limit for bit-for-bit decoding in AK240 tops out at files of 24-bit/192kHz resolutions. Astell&Kern stresses that many competing DACs that notionally can handle high-res files turn out in practice to downsample those files to lower resolution levels for playback. With the AK240 and AK380, there is of course no need to resort to such digital shenanigans.
Another notable difference between the players is that the AK380 incorporates “a voltage-controlled crystal oscillator (VXCO) high-precision clock with a reference jitter value of 200 femto seconds”—a feature the AK240 does not include. Accordingly, the AK380 offers noticeably lower jitter than does the already excellent AK240.
An even bigger difference, and one potentially very important for certain audiophiles and pro-audio customers, is that the AK380 dispenses with the AK240’s 10-band graphic equalizer, instead providing an extremely high-precision 20-band parametric equalizer (PEQ). By ‘highprecision’ I mean that the AK380’s impressive equalizer allows both gain and ‘Q’ settings for each EQ band to be adjusted in 0.1dB increments. What is more, the player allows users to create, name, and store multiple EQ curves, setting them aside for future use. For example, a user could conceivably create custom EQ curve settings to improve the frequency response of each of his or her favourite headphones or earphones, holding them in the player’s memory ready for use when needed. Astell&Kern says that the AK380’s extensive equalization functions are so processor intensive that the player must, as a matter of necessity, provide a dedicated audio DSD device to run them all.
One final differentiator between the AK380 and the AK240 is that the former supports a new Astell&Kern DLNA-compatible application called AK Connect, whereas the latter supported a similar but perhaps less elaborate DLNA application called MQS Streaming. The firm says that AK Connect allows the AK380 to “access or download music files stored on a computer on the same network (to which the AK380 is connected via Wi-Fi).” In turn, the application also allows music to “be played through Astell&Kern (network attached) speakers.” It is almost impossible to overstate the sheer range of system configuration options that AK Connect makes possible. In fact, depending upon the intended use context it is possible for the AK380 to serve as a Digital Media Player, a Digital Media Controller, a Digital Media Server (or network server), or as a Digital Media Player (or network player).
Honestly, we could probably discuss the AK380’s many features and functions for hours on end, but now it’s time to focus on the aspect of the player many readers will care about most: namely, its sound quality.
During my listening tests, I used the AK380 both as a standalone device and as a portable DAC/headphone amplifier connected to my reference Lenovo/jRiver Media Center-based music server. I also used a mix of reference earphones and headphones, including Noble Audio Model 4S CIEMs, JH Audio Roxanne CIEMs, Westone W60 universal-fit earphones, HiFiMAN HE1000 and HE400i headphones, and Oppo PM-1 headphones (with revised ear pads).
First and foremost, the AK380 consistently serves up a precise and firmly controlled sound characterised by transparency, openness, nuance, and an overarching sense of almost boundless attention to detail. Stated another way, the AK380 serves up clarity with a capital ‘C’ and an enchanting quality of musical lucidity that just won’t quit. In my experience, these qualities often caused even casual, first-time guest listeners to stop in their tracks and take notice of the pocket-sized player. I suspect this is because the AK380 tends to shatter pre-conceived notions of how a portable product will sound, instead delivering the sort of self-confident and self-assured sound that many would associate with premium-priced full-size components.
For instance, on ‘Again’ from Monty Alexander’s Calypso Blues: The Songs of Nat King Cole [Chesky, 24/192], the AK380 caught the fluidity and ease of Alexander’s piano, the woody richness of the accompanying acoustic bass, the restrained delicacy of the percussionist’s cymbals and snare rimshots, plus the almost evanescent low-level sound of Alexander humming along at times with the music (a detail so subtle that many DAC/amps miss it altogether!).
Similarly, on ‘Poison and Wine’ from The Civil Wars’ Barton Hollow [Sony, 16/44.1], the AK380 did a remarkable job with the passage where Joy Williams sings the lyric, “Your hands can heal/Your hands can wound”. As Williams sustains and extends the final word of the phrase, she is joined on that word—very faintly at first, and then more audibly—by Paul White, who deftly modulates his pitch so that his vocal line gently wraps around hers, eventually settling into a graceful harmony. Many DAC/amps can reveal such delicate moments to a point, but the AK380 handles them with far greater sensitivity and refinement than most.
Finally, the AK380 shows a good measure of dynamic swagger, provided you respect its overall output limits. I became a believer in its capabilities when listening to ‘Moten Swing’ from Clark Terry’s The Chicago Sessions: 1995-96 [Reference Recordings, 24/44.1 – HDCD]. In that track the DePaul University Big Band establishes a powerfully swinging but also fairly subdued groove, only to have Terry and the band’s horn section fairly explode into action. It’s a dramatic moment, one that the AK380 captures with authority and verve.
How does the AK380 fare as a music server? To find out, I played a test group of tracks from my reference server through the AK380, using it as a DAC/amp, then played the same tracks from the AK380’s onboard memory to see what, if any, differences I could observe. What I found was that both sounded very similar, but that the reference server gave just a smidgeon more edge-definition on transient sounds and—on good recordings—a hint of additional emphasis on the high frequency ‘air’ surrounding notes. In contrast, files played directly from the AK380 tended to sound a bit smoother and perhaps more rounded, but no less detailed. In short, I could live quite happily with either server (though I doubt I’ll ever get my Lenovo server and dedicated music drive to fit in my shirt pocket).
In sum, the AK380 is one of the most versatile, refined, and compelling personal audio products I’ve ever heard. It is undeniably expensive and may be priced beyond the budgets of many enthusiasts, this one included, but that doesn’t change the fact that it is a great performer and very desirable. Perhaps the strongest recommendation I can give is to admit that, down deep, I want one of these. And if you hear the AK380, you might want one, too.
TECHNICAL SPECIFICATIONS
Inputs: Built-in 256GB music library; USB Micro-B (32/384-capable); DLNA-connect servers, PCs, Macs, and NAS drives
Connectivity: Wi-Fi: 802.11 b/g/n Bluetooth: V4.0 (A2DP, AVRCP)
Outputs: Optical S/PDIF, 3.5mm minijack, 4-conductor 2.5mm balanced mini-jack, expansion for use with future, planned accessories
Software/Firmware: Windows: AK380 DAC driver Mac: MTP software
Storage: 256GB music library, standard; optional add-on microSD card at capacity up to 128GB
DACs: Dual AKM AK4490 DACs
Supported Formats: WAV, FLAC, WMA, MP3, OGG, APE (Normal, High, Fast), AAC, ALAC, AIFF, DFF, DSF
Sample Rates: PCM: 8 – 384kHz, 8/16/24/32-bits; supports bit-for-bit decoding up to 32/384
DSD Native: DSD64, DSD128
Frequency Response: 20 Hz – 20KHz, ± 0.053dB, single-ended and balanced 10 Hz – 70kHz, ± 0.56dB, single-ended; ± 0.055dB, balanced
Output Levels: 2.2Vrms, single-ended; 2.3Vrms, balanced THD + N: 0.0008% @ 1kHz, single-ended; 0.0007% @ 1kHz, balanced
Signal to Noise Ratio: 116dB @ 1kHz, single-ended; 117 dB @ 1kHz, balanced
Battery: 3,400mAh, 3.7V Li-Polymer battery
Dimensions (H×W×D): 112 × 80 × 18mm
Weight: 230g
Price: £2,999, or $3,499
Manufacturer Information: Astell&Kern
URL: www.astellnkern.com