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Astell&Kern

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BE THE ULTIMATE, AK240

Closer to Original

After successfully launching the AK100 and the AK120 models, we asked ourselves, “What is the ultimate sound quality?” After much consideration, we decided to move a step further with our goal, which is to deliver the sound “exactly as the artist had intended” for us to hear.
Moving from the AK100 to AK120, we decided to provide a Dual DAC setup to create better left and right channel separation with clearer sound quality.
We thought that the Dual DAC setup would be enough, but while developing the AK240, we felt the need to further improve sound quality in order to accurately reproduce the original sound recording. After countless hours of research and testing, we were able to find the answer.

The answer was to create both a balanced output and native DSD playback through the Dual DAC setup.
Now with the AK240, we can dare say that we have gotten “that much closer” to the sound quality of the original recording.

Native DSD Support

What is DSD?

DSD (Direct Stream Digital) is a digital audio file format originally developed for SACDs (Super Audio CD).
Regular digital audio file formats such as PCM (Pulse Code Modulation) is separated into 65,000(16bit) to 16,700,000(24bit) of information on the Y axis, and 44,100(44.1kHz) to 192,000(192kHz) across the X axis for digital signals.
DSD files have 1bit (0s or 1s) for Y axis and is separated into 2,800,000(2.8MHz) to 5,600,000(5.6MHz) of information for X axis.

Compared to regular audio CDs with 16bit/44.1kHz PCM format, SACD’s recording frequency goes up to 100kHz and the dynamic range goes beyond 120dB while maintaining sound clarity during the transmission.

16bit

1/44100s

Time

PCM

1bit

1/2822400s

Time

DSD

Native DSD Support

One of the approaches we decided that would help us move a step closer to the original sound quality was to provide native DSD playback without having to convert it into PCM.
This was indeed a difficult task. In order to provide native DSD playback on the AK240, we had to select a different DAC chipset.
Making the decision to change the DAC was not easy, but in order to reach our goal, we had to make a bold move which was to start from scratch.

We have asked ourselves: Does the DAC support Native DSD?
Will it allow for the Dual DAC setup? What else is needed for the perfect Native DSD support?

In order to answer these three questions, we have decided to use the Cirrus Logic CS4398 chip in the Dual DAC setup with an added exclusive XMOS chip that will allow for Native DSD support.

The process of setting up Native DSD support was not an easy task. Since the main CPU does not process Native DSD, we needed a chip that will work with it. It took us a long time, but we made it work. Through countless hours of testing, we were able to achieve Native DSD playback by having the main CPU process the data, send it to the exclusive XMOS chip, then through the DAC to deliver the sound.

AK240's Native DSD Playback Process
DSD
DSD
DSD Dedicated Chipset
DSD
DAC CS4398
Regular DSD to PCM Conversion Process
DSD
DSD
CPU PCM Conversion
PCM
DAC

Balanced Output

Unbalanced vs. Balanced Output

The unbalanced method is the most commo nly used basic method which consists of “left and right signals + ground line”.
This setup includes a ground line which blocks out external noises from the outside.
However, since the ground line cannot block out all of the external noises completely, external noises can be mixed into the signals that are transmitted, which then result in changes to the sound.
The longer the signals travel, the more external noises that will be mixed into the sound which is why it is used within a short distance of 1 to 2 meters.

Unlike the unbalanced method, the balanced method has an additional cold signal to compliment the hot signal which reduces the external noises.

Unbalanced method

hot signal

Balanced method

hot signal
cold signal
Ground or ground line
Ground or ground line

The balanced method has a few advantages over the unbalanced method.
The first advantage is that the hot signal and the cold signal will remove the external noises received.
The second advantage is increased output due to the 2 transmitted signals.

Noise Detected during
Balanced Output

Noise

hot signal

cold signal

Ground or ground line

Noise Removed
After Detection

Noise

hot signal

cold signal
reversed

Ground or ground line

Noise Removal Complete

signal
synthesis

Ground or ground line

Since the ground line cannot block out 100% of the external noises, noise will appear on both the hot and cold signals.
The alignment of the 2 signals allows the noise to usually appear at similar points where they will eventually be removed as the signals are transmitted.

Balanced Out and Dual DAC

Dual DAC meets Balanced Output

It did not take us long to figure out that the AK240’s Dual DAC and balanced output resulted in the best sound.
During the development of the AK100 and AK120, Astell&Kern's specific analogue amp setup was already creating full balanced analogue signals streaming from the DAC and we were able to move a step closer towards the original sound by then creating a balanced output terminal at the end.

Dual DAC'S Balanced Output
DAC
CS4398
L+
L-
L+
L-
GND
DAC
CS4398
R+
R-
R+
R-
GND
A-amp
L+
L-
R+
R-
phone
Output from other products
DAC
L
R
GND
phone

256GB of Massive Storage

Astell&Kern has created the AK120 Titan with a storage capacity of 128GB, but in order to support Native DSD, MQS, and massive audio files, we had to come up with the ultimate portable music player with 256GB of storage.
With 256GB of internal memory, about 2,500 MQS (24bit/96kHz, 4 minute-long, 90MB) songs can be saved. With the addition of a 128GB microSD card, the AK240 can support up to a total memory capacity of 384GB.

128GB

microSD Slot x1

(Max 128GB)

Max 384GB

256GB internal memory

MQS Streaming

Astell&Kern products have started to evolve into network players by providing Wi-Fi capability.

To listen to your favorite music, you no longer have to turn on your computer, search for your music, wait for the songs to download, connect your player via USB cable, and then wait for the files to transfer to the player.
Now with MQS Streaming, you can easily download or stream music directly from the AK240 by having the unit and your computer connected to the same network.

- "Astell&Kern MQS Streaming Server" software must be installed on your PC or MAC with a shared folder saved for MQS Streaming to work.

External HDD

Astell&Kern MQS
Streaming Server

Access Point

AK240
Streaming & Download

groovers

MQS music service provider "groovers" started with the launch of the AK100.
With the AK240, you no longer need to go through the traditional process of purchasing and downloading music on your computer, now you can easily download MQS music directly from the AK240 via the groovers store link on the home page of the AK240.
As long as you are in a Wi-Fi area, it is easy to download MQS music wherever you go.

  • groovers+ store is shown only if you set up Seoul as the time zone on the setting.
  • More music stores will be available in the future.

OTA (Over-The-Air) Upgrade

It has been 13 years since iriver has used the term "firmware".
Through these years, one had to check for new firmware updates by opening emails or checking the website.
Now with a Wi-Fi connection, you can receive instant notifications about new firmware updates and can update your unit whenever and wherever you are.

More Detailed 10-Band
0.5dB-step EQ Setting

More accurate EQ setting is available on the AK240 by doubling the bands (from 5 to 10 bands) and halving the dB steps (from 1dB to 0.5dB) available.
One can also create and save customized preset EQ settings to fit various music genres.

Full Touch Screen

Astell&Kern products have started to evolve into network players by providing Wi-Fi capability.

Compared to the AK120, the 3.31 inch AMOLED display on the AK240 is about 82% bigger to provide more information at a glance.
With the bigger display, the Full Touch screen makes it easy to navigate especially for smart phone users.

The playback and volume control buttons have been upgraded on the AK240.
Music tracks with long titles, such as a classical music, are displayed on 2 lines for better navigation.
Due to the speedy file scanning functionality, a separate DB scanning function is no longer needed and file search is available for easy access to music.

AK120 2.4 inch
AK240 3.31 inch

USB DAC

The AK240 supports Native DSD USB DAC function. (DoP method)

Through the USB connection, the AK240 can be used as a USB DAC which supports Native DSD playback.
The combination of the exclusive DSD chip and the Dual DAC in the AK240 goes above and beyond most computer sound cards and is able to create a greater sense of space and deeper sound while listening to your music.

- EQ setting cannot be used while in USB DAC mode on the AK240.

PC / MAC

Native DSD

PCM

USB

Line Out

Car

Speaker

Headphone

Exceptional AK240
Leather Case

In order to raise the bar of the AK240 even higher, much attention was devoted to the selection of leather for the case.
Minerva leather, originated from Badalassi Carlo was chosen for the case.
Badalassi Carlo was made by Professor Carlo Badalassi, who is known for his excellent skills with leather. Unlike modern methods, he uses a traditional method of making leather that requires extensive time and devotion.
His reputation is well-known among top expensive brands due to his focus on the leather quality over quantity.

The leather case for the AK240 was made from a process called “Full Vegetable Tanning”. This traditional method has been used in Italy for over 200 years.
The process brings out the special characteristic of leather while creating a natural tanning look.
A variety of trees and plants are involved in this tanning process which takes about 40 days to complete and only the most experienced professionals in Italy possess the skills to do it.

This special leather material has a lot of oil in it that will allow the leather to shine the more it is used.
Many tests and trials have been done with the creation of the leather case in order to highlight the unique design of the AK240.