This week, we tested the Astell&Kern AK240 digital audio player, flagship model of the iRiver DAPs, made up of the Astell&Kern AK100II, AK120, AK120 Titan, AK120II and AK240. The Korean brand has pulled out all the stops by fitting the AK240 with top-of-the-line functions. Compatible with audio files up to 24 bits and 192 kHz, DSD64 and DSD128, DLNA WiFi playback, Bluetooth, USB DAC mode, it features an extensive 256 Gb internal memory, 8.3″ touch screen, unbalanced and balanced headphone outputs, and a long-life battery. This extraordinary DAP has got the lot.
At the heart of the Astell&Kern, we find a pair of Cirrus Logic CS4398 DACs which run in parallel in order to drastically reduce jitter and distortion while increasing channel separation and the signal-to-noise ratio. This chip is compatible with PCM and DSD stereo audio streaming. MP3, OGG, WAV, ALAC, AIFF, FLAC and DSD files are all handled and decoded accurately.
The Astell&Kern AK240 comes with a Minerva Italian leather case (a Carlo Badalassi signature edition), a micro USB cable and-for our test copy-a Jon Bon Jovi album in MQA-format. This album comes on a micro-SD card with 24 bit/192 kHz WAV format files (MQA format).
The Astell&Kern AK240 can be configured in no time at all. Once you select your interface language, you just need to set your connection to the local WiFi network if you want to play the music shared by a DLNA server (NAS, Astell&Kern MQS server software…).
The Astell&Kern AK240 is fitted with a 256 Gb flash-type internal memory (NAND), which proved itself to be particularly high-performing. Our file copies ran off as fast as a USB 2.0 controller can handle, at a rate of 25 megabytes/sec. No specific software is required to transfer audio files to the DAP which is detected as a multimedia portable device (MTP protocol). Files can therefore be copied while listening to music.
The Astell&Kern AK240 is fitted with an SD micro memory card, which is compatible with the SDXC micro format. Capacity can therefore be increased by 128 Gb, in accordance with the current SD micro card offer.
Despite its uncommon design, the Astell&Kern AK240 is easy to carry. The leather case allows you to access all commands, apart from the micro- SD card reader, which isn’t a problem as the card doesn’t need to be removed every day. The volume control is easily accessible, whether you have it in your hand or set on a flat surface. It’s very easy to adjust the volume using your index finger as the notched volume wheel isn’t difficult to turn. The touch screen immediately displays the volume, which can be adjusted by sliding your finger in either direction.
The Astell&Kern AK240 operates with an Android proprietary version. This is a suitable choice which won’t throw off those who are used to Android or iOS. Perfectly stable and smooth, the AK240 OS is easy to use. The status bar at the top of the screen can be quickly scrolled down and it gives instant access to the device’s different functions: activating the WiFi and Bluetooth connection, line output at a fixed level, balanced headphone output, balance adjustment, equalizer, etc.
The Astell&Kern AK240 has a 10-band equalizer to correct frequency response at 30 Hz, 63 Hz, 120 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 16 kHz. Each level can be adjusted by more or less 12 dB, and you can even create your own response curve. Users can save their preferred equalization setting and name it as they wish. It’s worth noting that the Android keyboard, although small, is very easy to use.
WiFi and MQS server
The Astell&Kern AK240 can be used along with an MQS server, which can be downloaded from the Astell&Kern site. This software for both Windows and MacOS is a DLNA server, which allows you to listen to any audio, CD or studio quality files in WiFi. We didn’t encounter any transmission problems during testing but as with all wireless connections, the surrounding WiFi quality (the number of WiFi routers nearby and their transmission channel) and the listening zone configuration can have an impact on the streaming of 24 bit / 192 kHz files.
We listened to the Astell&Kern Ak240 with our reference headphones ? the Sennheiser PX100 and our usual selection of CD and studio quality FLAC files, as well as SACD DSDs. The initial notes are extremely soft with more emphasis in medium and upper-medium ranges (NB: the Pro setting of your equalizer offers a more linear delivery). This softness continues as the audio message gets more complex and the volume is increased. The bass range seems to be reduced and is discreet in the upper-bass, while our Sennheiser headphones are rather generous in this range. This impression is, however, deceiving as the articulation is excellent and the frequency response dives extremely low. The AK240 goes right down to infra-bass levels to the extent that it makes our headphone diaphragms crackle at a high volume. We noticed this when listening to MP3, FLAC and DSD files.
To sum up then, the Astell&Kern AK240 DAP offers a full and smooth audio delivery, full of well-structured fine details. The choice of components and their set-up are clearly a success.