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Astell & Kern PEE51 USB-C Dual DAC Cable Review – Je Ne Sais Quoi

Pros –

Low noise floor, Flexible braided cable, Ultra-premium build quality and aesthetic design, Smooth and refined sound, Spacious stage

Cons –

Slightly higher OI can limit versatility, Type-C plug isn’t case friendly, No accessories included

Verdict –

The Dual DAC Cable ultimately showcases greater refinement in both feel and listening than even its premium competitors, however, its higher output impedance especially makes it a far more situational buy.

Introduction –

Astell & Kern are one of the most renowned DAP makers on the market with a legacy of innovative designs. One example includes new SR15 which implemented a rotated screen in order to accommodate the ergonomics of handheld use. Upon such a foundation, the company has decided to address the death of the headphone jack in smartphone design with their new Dual DAC USB cable. This dongle-style DAC/AMP sports AK’s signature aesthetic and sound design with a full metal chassis and Dual Cirrus DAC setup – one handling each channel. In turn, the company promises the same premium experience provided by their DAPs scaled down into a hyper-portable form factor and at a reasonable price. As always, the company demonstrate their prowess with a carefully considered premium design that showcases profound attention to detail.

The Dual DAC Cable retails for $169 AUD or $199 NZD at the time of launch. You can read all about the DAC/AMP and treat yourself to a set here.

Contents –

Specifications –

  • Frequency Response: 20Hz – 20kHz
  • S/N: 118dB
  • THD + N: 0.0004% Unbalanced
  • Output Impedance: 2-Ohms
  • DAC: Cirrus Logic CS43198 x2
  • Sample Rate: PCM up to 32bit.384kHz, DSD64 (1bit, 2.8mHz) Native, Stereo, DSD128 (1bit, 5.6mHz), Stereo/DSD256 (1bit, 11.2mHz), Stereo
  • Input: USB Type-C
  • Output: 3.5mm Headphone
  • Dimensions: 17 x 50 x 10.3 mm
  • Weight: About 25g

Behind the Design –

Full Metal Housing

Reminiscent of their DAP designs, the Dual DAC Cable implements a design drawn from the concept of light and shadow. It features a robust zinc alloy build that provides a solid feel and daily durability. It has a noticeably different feel to aluminium with a premium weight and density alongside a different surface finish. The angular design was optimised for comfortable grip and one-handed use, AK also focused on providing a flawless, smooth finish. 

Dual-DAC Chipset

AK’s dongle features two of Cirrus Logic’s CS43198 MasterHIFI DAC chips supporting native DSD256 and 32bit/384kHz playback. This is Cirrus Logic’s power and space-efficient chipset superseding the CS4399. It has been designed with proprietary digital-interpolation filters and low jitter. Two chips have been implemented, one for each channel.

Independent Amplifier

AK forgo Cirrus’ integrated amplifier in favour of their own independent module – a prime differentiator from the vast majority of competing hyper-portable designs. The Dual DAC cable is built atop a micro 6-layer PCB with custom micro-resistors and tantalum capacitors designed to provide stable operation and improved capacitance for a dynamic audio performance. AK’s amplifier circuit offers 2Vrms output (no load)

Silver-Plated Copper Shielded Cable

An often-neglected part of dongle design, AK’s Dual DAC Cable features a custom-made large-gauge 4-core cable with copper noise shielding. It resembles a litz design with a combination of SPC and copper wire entwined around a centre aramid fibre damping core. Separate shielding is then applied over the cable to further shield the device from noise from the playback device.

Unboxing –

The Dual DAC Cable comes within a compact rubberized box and is nestled within a foam inlet. The experience is streamlined and no-frills. Given that the cable is soldered onto the device, no other accessories are included. For the more premium pricing, a carrying pouch would have been appreciated and perhaps a USB-A adaptor.

Design –

Visually satisfying design has always been a defining trait of Astell & Kern’s products and this same ethos is embodied here. For though the Dual DAC is one of the larger dongles I’ve reviewed, it is also one of the most premium. Furthermore, given its slim design, it doesn’t feel too substantial when stacked with a smartphone. The 2-piece Zinc alloy construction surely makes a strong first impression, feeling immediately more robust in the hand than competing plastic and aluminium designs. This experience is reinforced by an extrusion-moulded Type-C connector with matching zinc housing and the cable too impresses greatly; in my experience, one of the most overlooked aspects of dongle design.

AK’s custom 4-core braided cable is especially flexible, which in addition to the weight of the dongle itself, makes the device very easy to stack and handle alongside a smartphone. It also places less stress on the Type-C port of the playback device – and I found the dongle to provide very reliable connectivity here too. Solid rubber strain reliefs are to be observed on both terminations, however, one niggle is that he Type-C connector is quite large and features no protrusion. This means you will need a smartphone case with a large cut-out in order to use this DAC/AMP. Overall, beside the bulky connector, I found the look and feel of this dongle to be highly appealing and a prime differentiator from competitors.

Usability –

As with most competitors, the Dual DAC Cable is marketed as being plug and play on Windows, OSX, IOS and Android devices. Though I was unable to assess compatibility with Apple’s products, I experienced no difficulty using the dongle with either my Windows 10 laptop or Xperia 5 II smartphone, neither requiring unique apps or drivers to interface. On Android, however, a music playback app supporting DSD is required should you want to take advantage of this function.

The dongle also lacks an auto-power function which, to me, is a positive as it maximises compatibility and reliability. Once plugged in, the dongle powers on, denoted by a white LED indicator on its face. There’s no jack-mounted switch or timer which streamlines usability at the cost of power consumption (though realistically, the dongle would be unplugged when not in use). The dongle itself has no controls so the source devices handles playback and volume. I found the dongle to offer a good range here, suitable for sensitive in-ears with enough headroom for less sensitive headphones too.

As there is no integrated battery, the dongle is powered by the playback device. This may limit compatibility with some older smartphones that do not support power output, however, should not be a problem on modern Smartphones and laptops. Power drain was not substantial despite the robust amplifier – I found the Dual DAC Cable to draw less power than most competitors such as the Cozoy Takt-C. This suggests that the circuitry has been well-implemented to optimise efficiency. Do note that the dongle does not support 4-pole in-line remote signal but will support audio-playback on 4-pin remote cables.

Next Page: Sound & Pairings



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Ryan Soo

Avid writer, passionate photographer and sleep-deprived medical student, Ryan has an ongoing desire to bring quality products to the regular reader.


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