Review Index:

Calyx PaT Portable USB DAC and Headphone Amplifier Review

Subject: Mobile
Manufacturer: Calyx

Introduction: Improving Portable Sound

The Calyx PaT is very small USB DAC and headphone amp that can be used with PCs and mobile devices, offering the possibility of better sound from just about any digital source. So how does it sound? Let’s find out!

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The PaT is a very interesting little device, to be sure. It rather resembles a large domino and weighs less than 1 ounce thanks to an ultra-light aluminum construction. It requires no battery or power source other than its micro USB connection, yet it provides sufficient power (0.8 V output) for in-ear monitors and efficient headphones through its 3.5mm headphone jack. Inside is a proprietary mix of DAC and amplifier circuitry, and like other products produced by Calyx, a Korean company with little presence in the United States, there is the promise of a dedication to great sound. Did Calyx pull it off with the diminutive PaT?

Improving Portable Sound

Outboard DACs and headphone amplifiers for computers and mobile devices are nothing new, with recent products like AudioQuest’s Dragonfly a prime example in the portable USB DAC market (though it offers no mobile support). When I first heard about the PaT during CES it was still in the prototype stage, but I was interested because of the Calyx name if nothing else, as I already owned the Calyx M DAP and had been quite honestly blown away by the sound.

So what need might I have for the interestingly-named PaT (pronounced "paat", meaning "bean" in reference to the small size), which is itself a DAC that requires another device to play music files? It wasn’t until I had the opportunity to speak with Calyx president Seungmok Yi during CES (via video chat as I couldn’t attend the show) that I started realize that this could be a compelling product, not just for the $99 price tag - a bargain for an audiophile product - but because of how versatile the PaT can be. You don't have to identify as an "audiophile" to appreciate the clearer and more detailed sound of a good DAC, especially when so many of us simply haven't heard one (especially on mobile devices).

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Continue reading our review of the Calyx PaT USB DAC and headphone amp!!

First we'll check out the specs for the Calyx PaT:

  • USB DAC: Up to 16-bit/48 KHz
  • Audio Format: AIF, WAV, M4A, FLAC, OGG, MP3
  • Audio Output: 0.8 V, 3.5 mm jack
  • Connectivity: PC, Mac, Smartphones, Tablets
  • Colors: Blue, Gold, Red
  • Dimensions: (HxWxD) 60 mm x 32 mm x 6.8 mm
  • Included Cables: Micro USB OTG, micro USB to USB

Our thanks to U.S. distributor On Song Audio for providing the PaT for review!

To further touch on the $99 retail price of the PaT, this represents a very low cost for a DAC/headphone amp, almost too low to be taken seriously in some audiophile circles (where quality might be thought to increase equally with price). Sure there are inexpensive enthusiast kits available and polished products from companies like FiiO in the same price range (I've owned a couple), but for those who have seen and heard Calyx products it is clear that the company prides itself in delivering far more than one might expect at a given price point relative to the market. Granted, this is a small company in search of market share, but there is also a true sense of enthusiasm for the experience and certainly an obsessive attention to detail apparent when looking at the components and build quality of their products.

As a digital music interface the PaT offers a BYOD (bring your own device) solution.  It is compatible with many devices through the industry standard micro USB connection, and it has a clear focus toward current Apple iOS devices given the Apple-compliant audio controls (accessible from the unmarked buttons on the front of the minimalist PaT), though an adapter is required for use as Apple’s Lightning connection is not supported out of the box.

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The base is covered with a soft material that adds grip and protects it from vibration

In addition to iOS products the PaT also works with compatible Android devices (Android 5.0 Lollipop’s USB Audio functionality is a requirement). Your mileage will certainly vary when it comes to Android hardware, as not every phone or tablet offers support for output of digital audio via USB. I am currently using a Nexus 6 running Android 5.1 Lollipop as my primary mobile device, so naturally I plugged the Calyx PaT into the Nexus within seconds of seeing the device for the first time. Low and behold: Music! The micro USB OTG cable provided external DAC functionality for the music on the phone, and though the Apple-compatible controls on the front of the unit do not function on Android (an important distinction), volume and playback controls on the Android device worked perfectly.

Now onto to the PC, where the installation couldn’t be easier as no drivers are required. Simply connecting the PaT to a free USB port (a micro to standard USB cable is included) causes Windows 8.1 to detect a new sound device. An external DAC and headphone amplifier is bound to be better than anything installed in the system (within the limitation of the resolution the PaT can play, of course), though this potentially opens up an entirely new (and controversial) discussion about high-resolution audio formats that I won’t get into. The PaT supports files of up to 16-bit/48 KHz, and handles all of the the major formats (AIF, M4A, WAV, FLAC, MP3, OGG), which should be enough for most, but bear in mind that it won't replace a higher-end solution. As an audio company Calyx certainly doesn't ignore those interested in the hi-rez digital movement, as their Calyx M DAP/DAC offers support for virtually all ultra-high resolution audio formats including native DSD. They have simply tailored this product to a mobile market, and a low cost.

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The micro USB connection at the bottom of the PaT

Being a $99 device that is focused on existing mobile devices (and Apple in particular) is it understandable that Calyx does not implement conversion of audio sampled above 48 KHz, as mp3 and CD audio are 44.1 KHz formats. While high-resolution audio is popular in the audiophile community with sites such as Super HiRez and HD Tracks commonly offering files of 24-bit/96 KHz and above, anything purchased from iTunes or Amazon’s mp3 store - as well as anything ripped from a CD collection into even a lossless codec such as ALAC or FLAC - will be 16-bit/44.1 KHz. But as important (and technical) as sample rate and resolution can be with digital music, the most important thing is always going to be the sound. For instance a good implementation of CD-quality audio is still going to sound better than a poorly mastered 24-bit/96 KHz studio recording. But enough about bit depth and sample rate!

Next we'll go over the functionality and sound of the Calyx PaT across compatible devices!

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May 26, 2015 | 09:57 PM - Posted by bburnham37 (not verified)

Sorry, but I have to point this out -

"...from complex drum work focused on the symbols that challenges..."


not symbols.

May 26, 2015 | 11:09 PM - Posted by Sebastian Peak

Fixed the typo - thanks!

May 27, 2015 | 02:29 AM - Posted by sholling

I'm kind of curious how the PaT compares to the similarly priced FiiO E07K ($89 @ Amazon) and the high-end FiiO E18 ($159 @ Amazon) which contains its own power source. The last thing a smartphone user needs is yet another drain on the phone's battery. ;)

May 30, 2015 | 09:41 AM - Posted by JohnnyNismo (not verified)

I have an S.M.S.L M2 which I fricking love and also a Topping NX2. I'd love to see a USB DAC/AMP roundup from PCPer. There are a lot of great DACs out there for under $100 that only audiophiles know about. The masses must be let in on the secret.

May 30, 2015 | 10:58 PM - Posted by Sebastian Peak

I agree - the more exposure that affordable audio upgrades get, the more likely people are to try them out. The next step is to convince some manufacturers to send some DACs my way for a review!

March 16, 2019 | 03:57 AM - Posted by johnsnowkornar Here is a list. You may check this!!

June 1, 2015 | 11:46 PM - Posted by Mark_GB

Interesting device. I went to order one... Seems these people only want to work with dealers. None of the online dealers have it that I could find. It is a shame, I would have had one ordered by now.

June 2, 2015 | 12:01 AM - Posted by Tactile Devices (not verified)

Hi Mark,

We have the PaT in stock and ready for shipping. Please visit this link for more details:


Tactile Devices

June 19, 2015 | 11:53 AM - Posted by Tactile Devices (not verified)

We are now offering a special for free shipping in the USA on the PaT! Just thought you guys would like to know about this:

June 23, 2015 | 04:17 AM - Posted by oliolio (not verified)

is the battery consumption any extra compared to using for normal listening in the 3.5mm jack?

June 24, 2015 | 02:43 PM - Posted by Sebastian Peak

I didn't experience any noticeable change in battery life. The PaT only seems to use about the same amount of power as the phone's built-in audio output, but it would be interesting to know the exact numbers.

August 3, 2015 | 05:13 AM - Posted by Repsolgamma (not verified)


Read your article without truly understanding their considerable improvement my current computers onboard audio hardware and software.

You are a persuasive writer, making me perform an act I rarely do these days-hit that buy button!

Tell your boss a reader thinks you deserve a raise, this has to one of the most satisfying audio hardware purchases that I can remember.

Received my Calyx less than week after you wrote this story, and been re-listening to all my CDs after ripping them to WAV files. Not only have I gone through my music, been hearing them on all 6 of my headphones.

It's been a revelation, the PaT performs with such transparent clarity and a soundstage so detailed I can hear the shouts of many different individuals in the crowd of live concerts, the hum of electronics for the amplification systems used by the guitars.

Ryan's segments on the Calyx made me think they found no advantage using USB/DAC amplification, makes me wonder if he ever had the opportunity to actually listen to the PaT.

As a first time buyer of a device in this class, it's been a mind opener to experience the ilarge delta in improvement with audio that's now possible by expert optimization of DAC software tuning. I was skeptical until about 4 notes into my first listen of the Calyx playing one of my favorite David Gilmour solo songs "Mihalis".

My experience has been of pure joy listening to music of all types.

And for that I am greatly please that PCPER actually took the time to review, and that I had the sense to get my very own PaT.

Michael Berg

August 29, 2016 | 12:15 AM - Posted by Anonymous (not verified)

This is a good device how we can buy this??

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