The Astell&Kern AK70 MKII delivers a number of refinements
that easily makes this powerful, flexible, and sweet-sounding
hi-res digital audio player the best in class.
When I reviewed the original Astell&Kern AK70, it
checked off all the right boxes: Sleek styling, compact size,
superb audio performance, and a robust feature set. Now
Astell&Kern is back with an updated version of the
AK70, designated as MarkII or MKII. Diehard music lovers
who want to squeeze every ounce of fidelity from their music
won’t mind shelling out the additional $100 commanded by the
new model’s numerous refinements.
The player itself is the same 3.81-inch height, but measures a
hair thicker (0.59 inches) and wider (2.47 inches). It’s still
highly portable and fits in a front or back pocket with ease,
weighing a modest 5.29 ounces.
While the screen size remains exactly the same, the beveled
side and knurled volume dial are where you’ll notice the size
difference. Even though the volume dial is just a bit larger,
it makes a remarkable tactile difference when using the AK70
MKII. It felt more natural to use, and my thumb rested
perfectly along the AK70 MKII’s right side. The volume dial
sports a new, wave-knurled pattern, which gives a cool visual
when it reflects light.
The MKII’s all-aluminum body comes in your choice of two new
colors, cadet blue or black. My review sample came in the
former and it’s gorgeous. The DAP’s rear has a smooth, glass
finish, with a midnight blue hue underneath.
Dual DACs for audiophile performance
You’ll find further refinements inside: Unlike the initial
model, which had only a single Cirrus Logic CS4398 DAC, the
MKII has dual Cirrus Logic CS4398 DACs—one dedicated to each
channel. The left and right channels are fully separated from
input to output.
The Astell&Kern AK70 MKII plays back 24-bit/192kHz signals
bit-for-bit. It will downsample 32-bit audio with a sample-rate
converter. A 32-bit/384kHz file, for example, will be
downsampled to 24-bit/192kHz, and 32-bit/352kHz files get
downsampled to 24-bit/176kHz. DSD 64/128 files are supported as
Just about every lossless and lossy codec is supported,
including FLAC, ALAC, WAV, APE, AIFF, DFF, DSF, OGG, AAC, and
MP3. The player won’t playback protected AAC files, such as
those downloaded from Apple Music’s subscription-based
streaming service. You’ll want to use the highest-quality music
files you can, because the AK70 MKII is a very
revealing digital audio player. Excellent recordings in hi-res
sound great. Mediocre quality music files show all their flaws.
MQA is the only major codec not supported. I
asked Astell&Kern about MQA support and the team told me,
“We currently do not offer MQA support, but it is a feature we
are looking into. We do not have an ETA on when we may
support it.” If and when this happens, you’ll most likely be
able to add MQA support via a firmware update.
The AK70 MKII has upped the specs over the original in just
about every area. There’s more power output to drive a wider
range of headphones. Balanced audio output has gone from
2.3Vrms to 4.0Vrms. The signal-to-noise ratio has improved 2db
to 118dB for unbalanced connections, and +3dB for balanced
connections to 119dB. Crosstalk, total harmonic distortion and
noise, and even the battery have all received modest bumps,
too. The battery has gone from a 2,200mAh to a 2,500mAh 3.7V
Li-Polymer. Because of the dual DACs, however, you wont get
extra run time. Expect at least a solid 4- to 6 hours of
battery life with mixed use. The onboard 802.11n Wi-Fi and
Bluetooth 4.0 adapters will give you enhanced functionality,
but will also drain the battery faster.
Speaking of the battery, a standard micro-USB input is used for
both charging and data transfer. If you’re using a Mac, you’ll
need to download the free Android Transfer Utility to copy
files from it to the AK70 MKII. The AK70 MKII’s storage will
pop up and you can drag and drop files to the player. If you
have a particular folder hierarchy that you prefer, the
player’s interface will allow you to browse the internal
storage by folder structure in addition to the standard album,
artist, genre, and playlist views.
The AK70 MKII has the same interface as the rest of the
Astell&Kern lineup, and the AK70 MKII’s touchscreen
interface is excellent, though you will experience a fraction
of a second lag at times. The biggest annoyance is waiting 1-
to 2 seconds for album art to load in list or grid view. This
is a common issue with Astell&Kern players.
Swiping down from the top exposes all the player’s settings. If
you’re one of those people who doesn’t read user manuals,
you’ll drive yourself crazy trying to find the player’s
settings. Note that if you purchase one of the AK70 MKII’s
protective leather cases, the top portion of the leather case
will make it difficult for you to get a perfect swipe from the
Swiping down from the top exposes the player’s global search
feature, which is handy if you’ve loaded thousands of songs.
The only beef I have is that the screen’s small size makes
typing on the keyboard a bit difficult.
In addition to touchscreen options, physical buttons on the
left side give you the ability to play/pause and advance or go
back tracks. Just about every hi-res audio device limits volume
control to its analog dial. You therefore can’t use a
headphone’s inline remote control to adjust the MKII’s volume.
Incredible flexibility and power in a tiny package
If you think of the AK70 MKII as simply a digital music player,
you’ve totally missed the memo: This is one of the most
versatile hi-res DAPs on the market.
For example, you can connect the AK70 MKII to your Mac or PC
and use it as a high-end 24-bit/96kHz USB DAC, bypassing your
computer’s typically inferior internal headphone amp and DAC. I
plugged in the AK70 MKII to my MacBook Pro, set it to DAC
mode—and bingo—I was in business.
The AK70 MKII can work in the reverse, too, as a USB digital
audio out. Simply connect a USB OTG (On-The-Go) cable (not
included) to the micro-USB port and the AK70 MKII can serve up
music files stored on the device to your amplifier of choice.
It will also play DSD files via DoP (DSD over PCM), in which a
DSD file is sent on top of PCM data frames.
Network control and streaming options
The AK70 MKII will connect to any DLNA server; in fact,
Astell&Kern’s MQS streaming server is a free DLNA media
server available on both the Mac and Windows platforms. The
AK70 MKII will play any supported media file from your network.
Using the AK70 MKII’s AK Connect feature, I was able to access
both the MQS streaming server and my Twonky DNLA streaming
server. I browsed and played content in a variety of hi-res
music formats via both servers without issue.
The free AK Connect mobile app (available for both iOS and Andriod) creates a
seamless bridge between your iOS or Android smart device and
the AK70 MKII. I could use the app as a remote control for the
AK70 MKII and play content from the AK70 MKII on my
iPhone—including FLAC and DSD files that the iPhone doesn’t
natively support. In other words, the AK70 MKII can act as a
full-fledged, portable music server! The app is sometimes
sluggish; but all in all, it adds to an already rich package.
If you’re worried about storage capacity, don’t be. Yes,
there’s only 64GB of built-in storage, and there is only one
microSD expansion slot on the left side, but Astell&Kern
told me that the AK70 MKII was certified just a few months ago
to work with the latest SanDisk 400GB microSD cards. You can
therefore expand the system’s total storage capacity to 464GB.
(I didn’t have this type of available to me, so I couldn’t
independently test that claim.)
The AK70 MKII supports aptX HD, enabling you to stream hi-res
audio up to 24-bit/48kHz wirelessly via Bluetooth. While very
few wireless headphones support aptX HD today, you can easily
add Astell&Kern’s own XB10 Bluetooth amplifier
and DAC to enjoy wireless hi-res audio convenience with any
pair of wired headphones. The AK70 MKII will function as a
normal Bluetooth streamer as well. I paired it with my car’s
Bluetooth head unit easily.
Rounding out the player’s wireless features, the AK70 MKII
comes with native support for the Groovers+ and Tidal streaming
music services. I use Tidal on a regular basis and appreciated
being able to have that added streaming convenience. The
quality of streamed Tidal music is excellent; unfortunately, I
couldn’t take advantage of the service’s MQA streaming support.
It will lift the veil from your music
I paired the AK70 MKII with several over-the-ear headphones,
including the outstanding Focal Clear, Oppo PM2, and B&W P9
Signature. I also tested the player with Periodic Audio
Beryllium, Fiio F9 Pro, Aurvana Trio, and B&W C5
in-ear-monitors. I used the Fiio F9’s 2.5mm balanced cable
option with the AK70 MKII. The overwhelming majority of source
material was hi-res FLAC and ALAC files, CDs ripped as ALAC
files, and a handful of AAC-encoded files for comparison.
The AK70 MKII delivers a clean, detailed, controlled, and
dynamic musical experience that can only be described as
lifting the proverbial veil from your music. Every single time
I fired up a music track, I was struck by the low noise floor
and the black background that enabled the music to jump out
with outstanding definition. Seemingly trivial things—such as
the cartoon loop, growl, and static at the beginning of the
24-bit/88.2kHz version of Pink Floyd’s “Wish You Were
Here”—just popped. You don’t need to crank up the volume or ask
yourself, “what was that sound?” or “What did he say?”
Ratchetings things up on well-recorded tracks and quality
hi-res music files raises the stakes even more. The clarity and
timbre of Rebecca Pidgeon’s vocals on the 24-bit/176.4kHz FLAC
version of “Spanish Harlem,” from Chesky Records, were to die
for. I could easily follow the last decays of her vocals as
they disappeared into silence. The allure of female vocalists
such as Adele, Ruth B., Karen Carpenter, Norah Jones, Holly
Cole, Patricia Barber, and Stevie Nicks became a siren song. I
lost track of how many times I replayed Loren Allred’s “Never
Enough” from The Greatest Showman, trying to soak up
every vocal nuance.
Piano notes on the 24-bit/88.2kHz FLAC version of Daft Punk’s
“Within,” from Random Access Memory, were rich and
full bodied, devoid of that toy-like piano sound lesser players
can give. Dynamics on “Get Lucky,” with Pharrell Williams,
nicely conveyed the song’s energy.
Deep bass notes on Sarah McLachlan’s “Fumbling Towards Ecstasy
(Junior Boys Mix),” Bonnie McKee’s “Trouble,” “Imagine the
Fire” from the Dark Knight Rises soundtrack, Michael
Jackson’s “Dirty Diana” from Bad, and Kings of Leon’s
“Walls” were rendered with superb control and definition. Bass
had all the mastery, impact, and detail that makes it go from
plain old sound to foundational musical note.
Top to bottom, the tonal balance of the AK70 MKII was
excellent. Yo-Yo Ma’s Cello and Kathryn Stott’s piano on the
“Swan” from the album, Songs from the Arc of Life
literally made the hairs on my arms stand on end. I was able to
crank up the volume on the AK70 MKII without the hi-res
player’s amp exhibiting a hint of strain or harshness.
Don’t think there’s a difference between devices and file
formats? Let’s take the 16-bit/44kHz Trolls soundtrack
that I ripped from CD. Not an audiophile title by any means.
Played on the AK70 MKII, the bass on “Hair Up” starts and stops
on a dime—controlled and articulate. The soundstage on the AK70
MKII was three dimensional, instruments breathed in their own
space and time.
An iPhone 7 playing the AAC-encoded version flattened
everything out on the same track. Bass notes lost significant
definition, musical details were smeared, and the troll vocals
at the beginning of the song had a distinct hazy quality to
The same was true of the Black Panther soundtrack via
Tidal between the iPhone 7 and the AK70 MKII. The match strike
at the beginning of the title track, “Black Panther,” had a
crisp, defined top end, a clean midrange, and an articulate
bottom end on the AK70 MKII. Piano notes came from a more
three-dimensional, deeper soundstage. Not so on the iPhone. The
top end was muted, midrange veiled, and the bottom end
I happened to have Astell&Kern’s more-expensive Kann ($999
MSRP) on hand for a forthcoming review. There is indeed a sonic
difference when you move up the line. Comparatively speaking,
the Kann has an even smoother sound with stronger and more
dynamic bass than the AK70 MKII. When paired with an open back
pair of headphones like the Focal Clear or Oppo PM2, I
appreciated the Kann’s stronger bass output.
Nothing short of a musical powerhouse
Seriously, what more can I say about the AK70 MKII?
Consistently outstanding musical reproduction that will make
you hair stand on end; the ability to drive balanced and
unbalanced headphones; USB DAC functionality; micro SD
expandability; aptX HD over Bluetooth; flexibility and features
galore—and you get all this in a stylish form factor that fits
into your pocket for $700?
Let me just say it: Astell&Kern’s AK70 MKII hi-res DAP is
arguably one of the best if not the best pocket-sized
hi-res DAP packages around. Paired with an equally good pair of
headphones, the AK70 MKII becomes nothing short of a
high-octane, musical powerhouse. It earns my highest