Astell&Kern PEE51: an iron fist in a velvet glove


Mis à jour le 20 October 2021.

This week we reviewed the new Astell&Kern PEE51 portable audio DAC from the premium HD DAP manufacturer. The ultra-compact Astell&Kern PEEE51 is equipped with a dual Cirrus Logic DAC compatible with PCM streams up to 32-bit/384kHz, as well as DSD files up to DSD256 (DSD 11.2 MHz). Its analog amplification provides 2 Vrms of power on its single 3.5mm mini-jack output. Lastly, its non-detachable USB-C cable makes it exclusively suitable for use with an Android smartphone, or any other recent source with a USB-C port. Sold for €129, will the Astell&Kern PEE51 be able to compete with the market leaders?

Astell&Kern’s first portable 32-bit/384kHz compatible audio DAC, the PEEE51 promises to be a serious competitor to Audioquest DragonFly DACs and other equivalent models.

Astell&Kern PEE51: packaging & accessories

The Astell&Kern PEE51 portable audio DAC comes in a small black box decorated with a photo of the device, the device’s name and that of the brand. The back of the box features some of its technical characteristics.

Astell&Kern keeps it simple with the PEE51 portable audio DAC: included are the DAC and its non-detachable USB-C cable, a case and a brief user guide.

Inside the box is a small sleeve containing a multilingual instruction guide. Underneath it is the Astell&Kern PEE51 portable audio DAC, securely wedged inside a sheet of packing foam.

Astell&Kern PEE51: presentation

After gaining a good reputation with its excellent DAPs, Astell&Kern has surprised users by adding its first portable audio DAC to its catalog.

Design and power supply

The Astell&Kern DAC features aluminum casing and inherits the characteristic silhouette of the brand’s DAPs. In addition to being robust, aluminum forms an effective barrier against electromagnetic waves and ensures optimal operating conditions for internal components. The Astell&Kern PEE51 is powered directly via the connected source. Its USB-C port makes it compatible with the latest Android smartphones and computers equipped with a USB-C port. Power usage varies depending on the type of file played and the volume, but generally speaking the Astell&Kern PEE51 hardly affects the source’s battery life. Moreover, the PEE51’s high-end case doesn’t feature any controls. It is therefore necessary to use the source to control the volume or change tracks.

Dual Cirrus Logic DAC

The Astell&Kern PEE51 condenses all of the brand’s expertise into a compact system that can transform any smartphone or other recent source equipped with a USB-C port into an audiophile system. Once connected, the Astell&Kern PEE51 DAC converts digital audio streams from files stored in the device’s memory, as well as music played on online music services such as Tidal, Qobuz, Spotify, Deezer, etc. All that’s left to do is to pair it with hi-fi headphones or IEMs to enjoy your music.

A white LED conveniently lights up when the PEE51 DAC is connected.

To carry out these conversions, the Astell&Kern PEE51 uses a dual Cirrus Logic CS43198 DAC. The left and right channels therefore benefit from their own chip, which reduces noise and distortion. Thanks to this design, the Astell&Kern PEE51 portable DAC can efficiently read and convert PCM streams up to 32-bit/384kHz, and DSD files up to DSD256 (DSD 11.2MHz).

Note that in order to get the most out of the Cirrus Logic CS43198 DAC, it is preferable to use a playback app that allows you to bypass the limitations of your source’s operating system, especially under Android. Otherwise, playback will be limited to 16-bit/48kHz.

Analog amplifier

Like the double DAC, the PEE51’s analog amplification benefits from a particularly meticulous and optimized design, reducing distortion to a strict minimum. This circuit offers not only a natural and detailed reproduction, but also considerable power with 2 Vrms delivered on the 3.5mm mini-jack output. Thanks to its high-quality amplification, the Astell&Kern PEE51 portable audio DAC can power many headphones and IEMs, as long as they have a moderate impedance (preferably not exceeding 50 ohms) and a high sensitivity (from 100dB).

Silver-plated USB-C cable and 3.5mm mini-jack connector

For maximum convenience, the Astell&Kern PEE51 portable DAC and headphone amp is terminated with a short connection cable whose outer sheath is reinforced to withstand the stresses of everyday use. The conductors are made of silver-plated and OFC copper.

The Astell&Kern PEE51’s USB-C cable allows it to be paired with many Android smartphones and recent sources.

Silver-plating has been used to optimise the transmission of the very high frequencies that travel exclusively on the surface of the conductors. This improves the balance of the sound while adding a lot of detail. Moreover, the conductors of the Astell&Kern PEE51’s cable are wrapped around a Technora Aramid fiber core, a material that reduces unwanted noise. A separate shielding treatment is applied to the cable to limit distortion and block the noise of digital signals.

Equipped with a single 3.5mm mini-jack connector, the Astell&Kern PEE51 is compatible with many headphones and in-ear monitors.

As far as connectors are concerned, Astell&Kern has kept things simple by equipping its PEE51 DAC with a single 3.5mm mini-jack output, therefore guaranteeing compatibility with most headphones and in-ear monitors on the market.

Astell&Kern PEE51: key specifications


Dual Cirrus Logic CS43198 DAC
32-bit/384kHz and DSD256 compatible


Frequency response: from 20Hz to 20kHz (+/- 0.030)
Signal-to-noise ratio: 118 dB
THD+N: 0.0004%
Output impedance: 2 ohms
Output power: 2 Vrms


USB-C port
3.5mm mini-jack headphone output


Dimensions (WxHxD): 17 x 10.3 x 50mm
Weight: 25g

Astell&Kern PEE51: listening conditions

For our review, we paired the Astell&Kern PEE51 with an Android smartphone to listen to our Qobuz playlists (Sublime+ subscription) as well as 24-bit/96kHz and 24-bit/192kHz files stored on a micro SD card. In order to get the best performance with the PEE51 and especially to bypass our smartphone’s system, we carried out all our listening sessions via the USB audio player PRO application.

The combination of the Grado PS500e open-back hi-fi headphones with the Astell&Kern PEE51 DAC proved to be very pleasant.

Finally, the Grado PS500e open hi-fi headphones accompanied us during our test of the Astell&Kern PEE51 DAC.

Astell&Kern PEE51: our impressions


The Astell&Kern PEE51 portable audio DAC is very easy to use. It simply needs to be connected to a smartphone using the USB-C cable. At first glance, the fact that the latter is solidly attached seemed to be quite a disadvantage: what if it gets damaged over time? Ultimately, however, its flexible yet robust design put our minds at ease. We used it daily for almost two months, taking it in and out of our pocket, without it ever showing any signs of wear.

The sturdy design of the Astell&Kern PEE51’s cable put our minds at ease. It can be bent and unbent countless times without any signs of wear.

Furthermore, the fact that the cable is attached to the DAC is a considerable advantage as it prevents the music from cutting off due to a cable not being properly connected (something that has happened to us several times with a detachable cable and/or adapter). When you use a portable audio DAC, it is by definition carried around, regularly taken out and put back in your pocket. It is therefore important for the contact and the connection to be stable, which is the case with the Astell&Kern PEE51.

Listening sessions

Ghostemane – AI

We used this track to test the restitution of the lows and we were impressed. The bass was deep, sustained and tight, a real treat to listen to. As usual, Astell&Kern reproduced the music accurately, without embellishment.

Pink Floyd – Money 

Stereo effects and the entire frequency range are present in this track. The Astell&Kern DAC offered us a smooth and transparent reproduction. Each frequency range was perfectly layered, and none of them overpowered the others. The stereo was most intense during the very first seconds with the sound of the cash registers: a real delight!

Michael Bublé – Feeling Good

The Astell&Kern PEE51 honored this orchestral cover by the famous crooner. From the very first moments, we felt the impact of the mids delivered by the DAC, the singer’s voice was reproduced with great ease. The horns soared and struck a perfect balance between authority and softness. The PEE51 portable audio DAC demonstrated its qualities in terms of responsiveness and dynamism.

Eagles – Hotel California (long version from the album Hell Freezes Over)

This slow-beat song allowed us to savor the width and depth of the soundstage delivered by the Astell&Kern PEE51. The music had room to breathe and was incredibly spacious, much more so than when we used our headphones and smartphone without this DAC. It was like night and day. Combined with our Grado headphones, the listening experience was simply wonderful!

Astell&Kern PEE51: compared to…

Real Cable i-DAC 192 : sold at the same price, the Real Cable offers 24-bit/192kHz compatibility. One of the Real Cable’s advantages: in addition to being able to be used with any mobile device, both iOS and Android, its cable is detachable and can therefore be easily replaced. However, you have to use an adapter to connect it to a smartphone, which can lead to the sound cutting out. In terms of sound, the Astell&Kern PEE51 is more responsive and detailed.

Audioquest DragonFly Red : available for €199, the DragonFly is compatible with 24-bit/96kHz, compared to 32-bit/384kHz for the PEE51. The advantage goes to the Astell&Kern DAC, which offers softer highs as well as a more detailed and better defined soundstage. The benefit of a dual DAC is undeniable.

Astell&Kern PEE51: who is it for?

Perfect for use on the go, the Astell&Kern PEE51 portable audio DAC will satisfy anyone who wants to enjoy a high-quality sound reproduction with their Android smartphone, or any other recent source with a USB-C port. It will appeal to lovers of balance and transparency: the PEE51 provides a particularly accurate reproduction, with no need to adjust any frequency range. Ideal for use with hi-fi headphones, the Astell&Kern PEE51 DAC will work well with models that have low impedance and high sensitivity.

Astell&Kern PEE51: conclusion

Although the Astell&Kern PEE51 DAC is small, it provides a mighty performance. A real iron fist in a velvet glove, it offers a natural and no-frills reproduction: the highs are perfectly defined and very soft, the mids warm and the lows deep. While it impressed us when paired with open-back hi-fi headphones, it also has many strengths that make it an ally of choice for closed-back headphones.

We liked

  • Its transparency and balance
  • How compact it was
  • The build quality
  • The value for money

We would have liked

  • Nothing more at this price!

  • Share your opinion!

    This site uses Akismet to reduce spam. Learn how your comment data is processed.