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BE THE ULTIMATE, AK240 Stainless Steel AK240SS

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The unwavering strength of stainless steel.

At Astell&Kern, we study countless materials to remain faithful to our design philosophy: Deliver the unique beauty and pure essence of the raw material intact without needless processing.

"A strong, non-corrosive metal that does not easily bend or damage."
"A metal that can restore damage through polishing."

This type of metal is already widely used on high-end timepieces.
Unlike the previous iterations that employed duralumin, the Astell&Kern AK240SS is constructed with stainless steel to take full advantage of its inherent benefits.
Due to the extremely difficult processing techniques and high costs when compared to aluminum, stainless steel is generally reserved to high-end timepieces.
We at Astell&Kern have created the most special version of the AK240SS to date using stainless steel to bring you only the best.

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 AK240SS, 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.

This was indeed a difficult task. In order to provide native DSD playback on the AK240SS, 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.

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.

PCM

DSD

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

Balanced method

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 Removed After Detection

Noise Removal Complete

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

Unbalanced vs. Balanced Output

It did not take us long to figure out that the AK240SS’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

Output from other products

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 AK240SS can support up to a total memory capacity of 384GB.

256GB of Massive Storage

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 AK240SS 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

Compared to the AK120, the 3.31 inch AMOLED display on the AK240SS 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 AK240SS. 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

AK240SS 3.31 inch

USB DAC

The AK240SS supports Native DSD USB DAC function. (DoP method)

Through the USB connection, the AK240SS 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 AK240SS 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 AK240SS.

AK240SS Native USB DAC

Exceptional AK240SS Leather Case

In order to raise the bar of the AK240SS even higher, much attention was devoted to the selection of leather for the case.

The protective case made with leather from the world-renowned Tannerie Rémy Carriat complements the stainless steel body, adding even more value to the already-exceptional AK240SS.

DESIGN

Even though the body of ak240ss is just one piece, it goes through 12 stages of production until it is complete. The initial 6 stages involve the original materials being prepared, and the next 6 stages involve putting together all of those original parts. Each stage takes numerous hours which are worked on by our experts.

The unwavering strength of stainless steel.

Native DSD Support

Native DSD Support

What is DSD?

Balanced Output

Unbalanced vs. Balanced Output

Balanced Out and Dual DAC

Unbalanced vs. Balanced Output

256GB of Massive Storage

256GB of Massive Storage

OTA (Over-The-Air) Upgrade

More Detailed 10-Band 0.5dB-step EQ Setting

Full Touch Screen

USB DAC

The AK240SS supports Native DSD USB DAC function. (DoP method)

Exceptional AK240SS Leather Case

DESIGN

Specification