Introduction
Chances are that you use your notebook, tablet, or mobile phone to play music, especially through a streaming service like Tidal or Spotify. Sound quality is typically poor or mediocre. Integrated audio chips work in noisy electrical environments, and usually lack the necessary power to drive high-quality headphones.
Astell&Kern have released a USB-C DAC / headphone amp that provides an instant boost to your sound quality and lets you use your 3.5mm wired equipment with devices that lack a headphone jack, like some of the new mobile phones.
Description
The USB-C Dual DAC Cable ("Dual DAC") is based on twin Cirrus Logic CS43198 MasterHIFI Digital-to-Analog Converters. The CS43198 is a Delta-Sigma oversampling DAC that supports up to 384 kHz sampling rate / 32-bit resolution for PCM and DSD 256.
As expected from an Astell&Kern product, the Dual DAC is finished to a high standard. The compact metal Zinc alloy body (it is no bigger than a thumb-drive at 50 mm x 17 mm x 10.3mm !) houses an integrated circuit with bespoke designed capacitors and an optimised audio circuit to minimise power fluctuations and provide premium sound quality.
Astell&Kern claims that the analog amplifier is powerful enough to drive a variety of high impedance headphones with a 2V rms output level (condition no load). Output impedance is suitably low at 2 ohms, which should ensure lower distortion into low impedance headphones.
The fixed cable is a durable 4-core cable made out of a core of Technora aramid fiber, with a layer of thick silver-plated copper wrapped around it, followed by a further layer of copper wire in a spiral arrangement. The tastefully angled housing is carried over to the matching USB-C connector. A single LED indicates operation, while volume is controlled through the device it is paired with.
Operation
The Dual DAC worked without any issue with a variety of devices I tried - a Samsung Galaxy S10+ mobile phone, a Windows 10 notebook, and a 2020 Macbook Pro notebook. The bulk of my listening was done on the Samsung, playing music either through the Tidal or USB Audio Player Pro app. Power-draw was modest and I did not notice any adverse impact on battery life. Sadly, the Dual DAC is incompatible with iOS devices due to current limitations through their ports. Both high-resolution PCM and DSD files played without any issue.
The USB-C connector is quite large and may not fit properly through your mobile phone case. My case cut-outs were not big enough and I had to remove my phone case to plug in the Dual DAC. I am in two minds about the fixed lead. I like the idea of a fixed cable, but it is quite short and in the case of my Windows 10 notebook, the USB ports are located on the side of the screen, which left the Dual DAC suspended in the air.
Sound Quality
The Dual DAC provided a significant uplift in sound quality and drive capability, with the improvements most noticeable on difficult to drive headphones. I tried it with a variety of IEMs, as well as two headphones - a Beyer DT880 (250 ohm version) and an E-MU Teak. Most of my listening was done on the E-MU for reasons explained below.
The most striking improvement was in the reproduction of low-frequencies. The Dual DAC added a tight punchiness that went deep. Vocals gained clarity and refinement, adding sweetness and uncovering details that were previously obscured. High-frequencies too gained extension and airiness, giving music a brighter and more illuminated tone. The soundstage opened up, with an increase in dimensionality, and the sense of acoustic space in the recording.
Pairing the Dual DAC with IEMs brought improvements in sound quality, but the Dual DAC's strength was in bringing extra current and voltage drive for more difficult to drive headphones (within reason). While the DT880 showed improvements with the Dual DAC, it lacked the dynamic freedom and ease compared to my desktop headphone amps. The E-MU Teak is easier to drive in comparison and was very comfortable with the Dual DAC, even at high levels. Given the compact size of the Dual DAC, this is a reasonable compromise.
I was impressed with the high level of sound quality delivered by the Dual DAC and can highly recommend it to Android phone users who want the best sound quality on the go, or to business travelers that need a high-quality and portable audio rig.
Conclusion
From a pricing standpoint, the Dual DAC is a premium product that carries a corresponding price tag. The competition offers similar products, some at a lower price point with features like balanced drive capability. I think the pricing is fair, and like any Astell&Kern product, you get lasting pride of ownership.
The Dual DAC will be available in May 2021 at a retail price of S$ 189- Highly Recommended.
You can purchase the Dual DAC from AV One (https://av1group.com.sg), Connect IT, E1 Personal Audio, Headphones.SG, Jaben, Stereo Electronics, and Treoo.com.