Astell & Kern PEE51 Review

Astell & Kern is one of the most notable names in the realm of digital audio players. Many of their efforts have been critically acclaimed for producing some of the most high-end systems around. However, those who might be on a strict budget may not have ever bothered to seek out any of their products. Understandably, some might not be able to afford even their most inexpensive products, but they do offer items outside of DAPs that you might be interested in.

I’ve been looking at more DAC adapters recently, such as the Periodic Audio Rhodium. Now, I’ve gotten the chance to try out the unfortunately named PEE51, a USB-C DAC amplifier made by Astell and Kern. They make a few accessories, but these are their first portable DACs, only going for $149. Is it worth it?

A&K Shell


From just taking a look at the PEE51, and holding it in my hand, you can tell that Astell and Kern bring their level of durability to even their more inexpensive devices. This is one of the most high-grade DAC adapters I’ve come across. It uses a full metal housing design with edges as sharp as some of its DAPs. This makeup of materials tells me that Astell and Kern are putting a lot of effort into PEE51, compared to other brands that use plastic. The main chassis isn’t the only element that uses high-grade components. It uses a cable with a silver-plated copper shield that connects the housing to the USB-C connector.  

A&K plug


Inside this metal, housing is a dual-DAC chipset for premium high-resolution listening through your portable device. Specifically. It features two Cirrus Logic CS43198 MasterHIFI DACs which support native DSD256 and 32bit/384kHz playback. 

A&K 3.5mm jack


I mainly used the PEE51 with a Samsung Galaxy Android phone. Each earphone I tested was given a great level of signal that always provided plenty of headroom. It was easy to find an ideal loudness without feeling like the sound was blasting in my ear. There’s a more natural output here that I appreciated more than some adapters that focus more on greater amplitudes. 

A&K and Vesper

Sound Quality

Out of the couple of IEMs, I used to test out the PEE51, there were a few main qualities I noticed in each pair. First, there’s the soundstage, which brings a lot of the sound inward more than expands them. There’s a certain level of depth that still persists, but the headspace is noticeably reduced. I felt that the PEE51 leaned more towards accuracy here, not trying to impress you but rather give you a reliable image more faithful to the mix. It worked great for warmer timbres, showcasing a much more intimate quality than a lot of other portable DACs.

What impresses me the most about this DAC is the level of separation. While it fails to reveal much in the realm of spatial imaging, the spaces between elements do a lot to make the sounds clear and consistent. This worked exceptionally well while listening to the Queen of Audio Vesper, which impressed me even more with its ability to reveal more articulation while keeping its color. The Campfire Andromeda also had some interesting tones when paired with the PEE51.

The soundstage is reduced, but the warmth in the low-mids is even richer than before. It showcases superior immersion with acoustic and folk tracks, while I felt the Vesper fared better with electronic and more instrumental-heavy selections. The Andromeda also felt a lot quicker in its transient response, bringing a suitable level of impact to its sound signature. You could also feel this in the Vesper but not as rounded in the bass as the Andromeda.

The bass is also less cloudy in the Vesper, clearing out some unneeded resonances and giving the timbre more room to breathe. Midrange elements also come off a lot smoother, and more consistent in both IEMs. It gives the timbre a bit more liveliness, especially in the Vesper. Vocals appeared with much more authority in some tracks without sounding like they were more forward in the mix. As for the treble, there’s some great texture here. The Andromeda’s highs were as sparkly as ever, showcasing glistening qualities that I’m quite the sucker for. As far as the vesper goes, the highs were a lot airier which suited my ambient tastes well. You’ll never hear anything too bright, or too piercing, but I would have liked to hear a bit more crispiness to add that little extra flavor in the treble.


The PEE51 is one of the most well-made DAC adapters around. Astell and Kern have found a way to produce an inexpensive accessory while maintaining the level of expert craftsmanship that exists in their higher-end products. Its sound signature is also delightful, especially if you like warmth and texture. I wish the soundstage was a bit more expansive, but you can’t deny the exceptional level of separation and clarity it includes in its place.

Using the PEE51 and the Vesper together brought a high-end sound for an affordable price, proving that you can obtain an audiophile sound with the right accessories. If you’re planning on having a mobile audiophile set up, but are on a budget, the PEE51 might be exactly what you need.

Pros and Cons

Pros: Build, Transient response, Separation, Warmth

Cons: Reduced width

The Astell & Kern PEE51 is available at Audio 46.

Compare the ranking of various headphones, earbuds and in-ear monitors using our tools.

Discuss this, and much more, over on our forum.

MAJORHIFI may receive commissions from retail offers.
Previous articleSee Audio Kaguya Electrostatic IEM – Review
Next articleKinera Reveal Imperial Skuld 5 Balanced Armature IEM
Alex S. is a sound designer and voice-over artist who has worked in film, commercials, and podcasts. He loves horror movies and emo music.