Overview: The Astell&Kern AK240 from iRiver is a portable
high-resolution music player which comes closer to the original sound than its
predecessors, the AK100 and AK120. The AK240 takes the dual DACs
(digital-to-audio converters) of the AK120, and adds a balanced output and
native DSD (direct stream digital) playback for better sound quality. It has a
huge internal memory so you'll be able to store thousands of high-resolution
music files. The AK240 has a 3.31" AMOLED touchscreen display, plus built-in Wi-Fi and Bluetooth.
Note: Direct Stream Digital (DSD) is the digital audio file format
originally developed for SACD (Super Audio CDs). DSD features 1-bit /
2.8MHz-5.6MHz resolution, with wide frequency responses up to 100kHz and
dynamic range beyond 120dB.
Construction: The AK240 is only 2.59"W x 4.21"H x 0.68"D, and weighs
6.5 ounces. It is made from gun metal-colored aircraft-grade duralumin, and
comes with a fine leather case to protect it from scratches. Analog controls include
a rotary volume knob on the right side, and Play/pause, Previous/rewind, and
Next/fast forward buttons along the left side.
Digital Storage: The AK240 has a built-in 256 GB internal memory. You
can also insert a 128 GB microSD card in the memory card slot on the side of the
device to bring the total memory capacity of 384 GB. That's enough storage for
approximately 3,750 four-minute songs, recorded at 24-bit/96kHz resolution.
Dual DACs: The AK240 is equipped with two Cirrus Logic
CS4398 DACs that support up to 24-bit/192 kHz bit-to-bit decoding. An
exclusive XMOS chip was added to allow Native DSD support. One DAC is used for the left channel, and one
for the right channel. Each DAC delivers outstanding performance with
the following specifications:
- Signal-to-Noise Ratio (@1kHz): 116dB unbalanced, 117dB balanced
- Crosstalk (@1kHz): 130dB unbalanced, 135dB balanced
- THD+N (@1kHz): 0.0007% unbalanced, 0.0005% balanced
- Frequency Response: 20Hz-20kHz (±0.023dB); 10Hz-70kHz
USB DAC: You can use the AK240 as an external USB DAC which
supports Native DSD playback. With the Dual DACs and the exclusive DSD chip, the
AK240 delivers much better sounding audio than your computer's built-in sound
the unit via USB from your computer and listen to your stored digital music with
headphones, powered speakers, or home stereo. The USB DAC is compatible with
Windows XP (32-bit), Windows 7 (32- & 64-bit), Windows 8/8.1 (32- & 64-bit), and
Mac OS X 10.7 and up; Sampling Rates: 44.1kHz - 192kHz; Bit Rates: 16-bit /
24-bit; DSD Support: DSD64 (1-bit 2.8MHz), DSD128 (1-bit 5.6MHz).
Balanced/Unbalanced Outputs: The Astell&Kern AK240 offers
both balanced (L+/L-/R+/R-) and unbalanced outputs (L+/R+/GND). Balanced outputs
have an additional "cold" signal to compliment the hot signal, which reduces
external noise and increases output. The balanced output is a 4-conductor 2.5mm
port (1 ohm) on the side of the device, and can be used with earphones or
headphones that support balanced audio connections. You can also connect an
external audio device to the AK240 by connecting to both the earphones port
(ground) and the balanced port (LR).
Digital Audio Files: The AK240 is capable of playing high resolution digital
music up to 24-bit, 192kHz, the same as used in the music mastering process.
This Mastering Quality Sound (MQS) includes all of the high resolution formats,
including WAV, AIFF, FLAC, and ALAC. These lossless files provide approximately
6-1/2 times more detail than a CD (16-bit, 44kHz), and can be played at sample
rates of 8kHz-192kHz and 8/16/24-bits per sample. In addition, the unit can play
MP3, AAC, WMA, OGG, and APE compressed audio files.
User Interface: The AK240 features a high-quality user interface to
make it easy to find and select your music files, change the volume, and
adjust the sound:
- 3.31" LCD Touchscreen: The full-color LCD touchscreen has a
resolution of 480 x 800 pixels. The screen displays the title and artist of
the currently playing song, along with elapsed and remaining time, with the
album art in the background. On the touchscreen, you can touch the
Play/Pause, Previous/Rewind, or Next/Fast Forward icons to control playback.
You can make adjustments to the EQ, set the repeat and random modes, and add
the song to a playlist, all using the touchscreen interface.
- Rotary Volume Knob: The AK240 has a side-mounted analog-style
rotary volume knob. The volume control range is 00.0 to 75.0 with detents at
every 0.5. As you adjust the volume, the volume range is shown numerically on the display.
- Hardware Control Buttons: There are four physical buttons on the
unit: a top-mounted power button, along with side-mounted Play/Pause,
Previous/Rewind, and Next/Fast Forward buttons.
Drawing Equalizer: The AK240 has a 10-band Equalizer that lets you set
the EQ levels by "drawing" the curve on the touchscreen. You can set the levels
of each band from -10dB to +10dB at 32kHz, 62Hz, 125Hz, 250Hz, 500Hz, 1kHz,
2kHz, 4kHz, 8kHz and 16kHz. Each
band can be set one at a time by touching the desired level on the screen, or
set them all at once by a single swipe of the finger across the screen in the
shape you desire.
Micro-B USB: The AK240 has a Micro-B USB port on the bottom of the unit
for connecting the unit to your computer for downloading music files and for
charging the battery. The AK240 is compatible with Windows XP, Vista, 7 and 8/8.1,
as well as Mac OS X 10.7 and up.
Wi-Fi Capability: The AK240 features built-in Wi-Fi (802.11
b/g/n--2.4GHz), allowing you to connect the device and your computer to the same
network for streaming and downloading music. With the MQS Streaming Server
software installed on your PC or Mac, you can use the AK240 to access music
files stored on your computer's hard drive or a connected HDD. In addition, the
Wi-Fi connection allows you to receive notifications of new available firmware
updates (OTA Upgrades), allowing you to download them on the spot.
Bluetooth: The AK240 also has built-in Bluetooth V4.0 for
connecting a Bluetooth device to listen to music wirelessly. DSD playback is not
available via Bluetooth, and performance may be limited for high-res playback;
48 kHz or lower resolution is recommended). You must maintain a distance within
8" of the paired Bluetooth device for best audio quality and connection quality.
Car audio Bluetooth connections are not supported.
Power Requirements: The AK240 is equipped with a 3250 mAh 3.7V
Lithium-Polymer battery. The battery charges via USB in about 4.5 hours. A fully
charged battery can provide up to approximately 10 hours of continuous playback