AK4493S / AK4490R Advanced VELVET SOUND Technology

Developer's Interview

March 2022

Inside Story #03


AKM has released the AK4493S and AK4490R DACs, as new products under the VELVET SOUND brand. We interviewed the developers about the latest evolution of VELVET SOUND technology.

◆ Please tell us about the concept behind the newest  VELVET SOUND DACs, the AK4490R and AK4493S.


The "S" in the part number AK4493S stands for "Superior," and the "R" in AK4490R stands for "Rich." Both of these products are even closer than the original versions to the ideal of flawless original sound reproduction, and you can feel the evolution of our design technology when listening through them.

◆ Please tell us about the Advanced VELVET SOUND technology


First of all, we have changed the manufacturing process. This change could have led to degradation, but we turned it into an evolution. This was possible because in addition to our experience in audio circuit design, we have a deep understanding of semiconductor process technology.

◆ How has the design technology evolved?


Let me elaborate upon two specific points of evolution.


The first is impedance. To put it in simple terms, you can compare impedance to the width of a road. You can increase the number of lanes, as you would on a highway, to improve the flow of the desired audio signal. For a noisier circuit, though, you'd want to make that road so narrow that you - or the noise, in this case - could barely walk through it. The AK4493S and AK4490R have been redesigned to optimize signal and noise path impedance, which achieves a dynamic and responsive sound while reducing unnecessary power consumption.  This optimization is integral to the evolution of VELVET SOUND.


The second point of evolution is our treatment of noise itself. There are many kinds of noise, some peculiar and grating, and some that is not as unpleasant. Based upon our understanding of the character of different kinds of noise, we have changed the distribution of  noise drastically. So while the devices' noise specs are quantitatively unchanged, the audible noise characteristics are qualitatively even better than before, and the sound of the content itself is richer and more delicate, as well as more complete.

◆ AKM Audio Meister - please tell us about the sound of the AK4493S and AK4490R.


The AK4490R and AK4493S deliver a dynamic and responsive sound. In order to convey the atmosphere of a concert hall, playback must accurately reproduce the trailing sound that lingers at the end of every musical passage as the last note fades into silence. Our design methodology ensures that this crucial decay is faithfully expressed. 

◆ Pleae share some message to users.


We are proud to present the AK4493S and the AK4490R. We hope you will experience the world of Velvet Sound's faithful re-creation of the original audio experience, just as it occurred when it was recorded.

Seiko Makamoto Seiko Makamoto

Seiko Makamoto, VELVET SOUND Product Development Expert

Manager, Group 3 Product Development Dept.1
Product Development Center, Asahi Kasei Microdevices Corporation

Tomonori Sato Tomonori Sato

Tomonori Sato, Audio Meister 
Marketing & Sales Center, Asahi Kasei Microdevices Corporation

Sato entered Asahi Kasei Corporation in 1998. Since then he has been involved in the development of ICs for audio equipment and internationally pioneered the planning of 32-bit DACs and ADCs. In 2009, he became the Audio Meister of Asahi Kasei Microdevices. Since then, he has brought into the world the VELVET SOUND series of DAC chips, including the AK4490, AK4497, and AK4499. They are used in numerous pieces of audio equipment. One of the recordings he uses to review sound quality is the 1988 Philips Saint-Saens: Carnival of the Animals performed by Argerich, Kremer and others. His hobby is making speakers and he uses an exclusive Fostex unit to listen through his own enclosures.