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Questyle M12 Mobile Phone Headphone Amp and DAC - Great HiFi On the Go

01-01-2022 | By Juan C. Ayllon | Issue 119

Chances are, you spend a lot of time either behind a desk, on a computer, or out and about without access to a quality home high fidelity stereo. Or, if you're like me this past season, your system is out of commission, tucked away in storage while renovations are being performed in your home. That's where the versatile Questyle M12 Mobile Phone Headphone Amp and DAC can step in and deliver your high fidelity fix with great aplomb.

A Little Background

Founded in 2012 by CEO Jason Wang, Questyle Audio Engineering is dedicated to designing and manufacturing high resolution music players for portable and car use, and state of the art audio equipment for studio monitoring and top-tier players, as well as wireless audio for home and customized installation. Developed by Wang and his engineering team, their products have won the CES Innovation Award and the iF Industrial Design award, as well as dozens of others in Europe, Asia, and the United States. Questyle products are manufactured by the Foxconn Technology Group.

Released in 2021, the diminutive M12 dongle DAC renders PCM up to 384kHz, and DSD loads up to DSD256 to great effect. But before we jump into a test drive, let's take a peak under the hood.


Constructed out of machined aluminum, the M12 is 2" W x .65" H x .32" D (51 mm x 16.5 mm x 8.1 mm) and comes in silver or black. It comes in a handsome slender 5 3/8" W x 2 9/16" H x 1" D (136.53 mm x 65.02 mm x 25.4 mm) black box with a cloth tab on its pull out drawer, where you will find the M12 tucked into a removable black foam section, with several adapters located below. 

The required operating systems to run it are as follows:

  • Android phone and pad: Android 5.0 and above
  • PC: Windows 10 1803 and above
  • Apple cellphone: iOS (you need an OTG cable for Lightning to Type-C)
  • Apple Computer: Mac OS
  • DAC employed: ESS USB DAC ES9281AC chip
  • DAC capabilities: PCM 32kHz - 384kHz (16/24/32Bit), DSD64 (1Bit, 2.8MHz), DSD128 (1Bit, 5.6MHz), and DSD256 (1Bit, 11.2MHz)

The M12 also unpacks and plays MQA (Master Quality Authenticated), which is a proprietary audio codec for high fidelity digital streaming and music downloads. 

Image courtesy of Questyle Audio Engineering

The M12 boasts a frequency response of plus or minus 0.1 dB (20Hz to 20kHz) and an ultra low distortion level of THD+N of 0.0003 percent. 

Image courtesy of Questyle Audio Engineering

Using its built-in smart detection circuit, it will automatically adjust its headphone power output to match the impedance requirements of headphones ranging from from eight to 600 ohms.

RL=16Ω – Po=46.11mW
RL=32Ω – Po=26.71mW
RL=300Ω – Po=12.26mW

When the M12 detects that impedance is less than 70Ω, it will self-adjust to low gain output. When it is more than 70Ω, the M12 self-adjusts to high gain output. When it is more than 600Ω, it will automatically switch to 2Vrms line out.

A gain indicator light turns red for high gain and green for low gain, while the data indicator light turns green for PCM, red for DSD and magenta for MQA. 

An Immersive and Spacious Experience

Some people will say, "Measurements, schmesurements! How do I know it doesn't sound etched or clinical?" I'm glad you asked.

Over a period of several months, I listened to music served up by my iPhone Xr cell phone, a MacBook Air, and a Bang & Olufsen HP Elitebook using the M12 and, alternatively, a pair of Fostex T50RPmk3 headphones ($159.99, 101.99 dB sensitivity, 53.64 Ohm load) and the KLH Ultimate Open-Back Over Ear Headphones ($299.88, 97 dB sensitivity, 18Hz-22kHz frequency response). While playback over the iPhone was excellent, it used up battery power faster than I'd like. Subsequently, most of my listening time was conducted on the laptops. 

Both headphones yielded favorable results, with the KLH Ultimate a little more comfortable and playing louder at the same computer volume setting. What follows, then, are impressions from a listening session with the KLHs. 

The M12 is very detailed, balanced and engaging in its delivery. For example, it spotlights the warmth and vulnerability of Neil Young's countertenor vocals in "Song of the Seasons" (Barn, Qobuz 24-Bit, 192 kHz, Reprise December 10, 2021), contrasting with the rich, but harder edges of his harmonica and Nils Lofgren's acoustic guitar. It's rich and full bodied, with Ralph Molina's weighty bass and Billy Talbot's drumkit locking in the rhythm, and Lofgren's accordion adding intrigue and texture to this luscious and palpable mix. 

In "Goin' to Chicago" (Kurt Elling, James Morrison: Live in New York. 16-Bit, 44.1 kHz Qobuz, Universal Music Austrailia Pty. Ltd, April 26, 2019), Stu Mindeman's piano is deep and resplendent, its decaying notes pierced by Ulysses Owens' crisp ride cymbals and snare; enjoined with Clark Summers' bass and James Morrison's adroit trumpet comping, they form a solid offensive line as baritone Kurt Elling quarterbacks a virtuosic performance worthy of Birdland's best, bowling guests over with his stellar vocal runs.  One gets a feel for the room and its approving patrons, whose laughter and hearty roars are fully fleshed out, entreating you to join this intimate jazz club experience.

The M12 does Indies Rock well, as demonstrated in Amythyst Kiah's "Black Myself" (Amythyst Kiah. Wary + Strange. Qobuz 24-Bit, 96 kHz, Rounder, June 18, 2021). Kiah's emotive, controlled muscular vocals and blaring, distorted blues guitar riffs are supported by bandmates Rhiannon Giddens, Allision Russel, and Leyla McCalla belting out her anthem song with grunge, a punchy drum kit, and a guttural bassline. It's a visceral treat.  

In Herbert Von Karajan's rendition of "Finale (Adagio-Allegro molto e vivace)" (Herbert Von Karajan, composer: Ludwig von Beethoven. Beethoven: 9 Symphonies (1963). Qobuz 16-Bit, 44.1 kHz, Deutsche Grammophon (DG) January 1, 2014), the strings, woodwinds, brass and percussion arise and fall as one in a powerful and moving performance. The textures, and timbres of the instruments rendered in a three dimensional hall are astonishing and not to be missed!

If you are in a place far removed from a quality two channel setup and need your HiFi fix, the Questyle Audio Engineering M-12 Mobile HiFi Headphone Amplifier with DAC delivers the goods. As their site says, "(the) M12 allows all mobile phone users to break through limitations of technology, cost, and size of the audio circuit integrated into mobile phones, and...enjoy lossless music from streaming anytime in any place." And it does so with realism, verve and panache!

Hence, I give it my hearty recommendation.

M-12 Mobile HiFi Headphone Amplifier with DAC

Retail: $139.99

Questyle Audio Engineering