Questyle Audio M12 portable USB D/A headphone amplifier

There are words that, for reasons I can't fathom, I cannot stand. One such is "dongle." So when Bluebird Music's PR rep emailed me to ask if I would be interested in reviewing a new dongle from Chinese company Questyle Audio, I shuddered. But I must admit that "dongle" rolls off the tongue a lot more readily than "portable USB D/A headphone amplifier." I put aside my grammatical quibble and agreed to a review.

The M12
Priced at $139.99, the tiny, 2"-long M12 Mobile Hi-Fi Headphone Amplifier with DAC features a case machined from aluminum. On one end is a USB-C port. On the other is a 3.5mm stereo headphone jack. On top are two multicolor LEDs, one to indicate the gain setting, the other the incoming data status. On the bottom are logos for MQA, ESS, and "Current Mode Amplification." That's all there is to see.

The M12's complexity lies inside. "Current Mode Amplification" refers to a "patented SiP amplifier module" that Questyle says provides "high" current output, "vanishingly low" distortion, and "astonishing noise levels of –130dB." The "Smart Impedance Detection" feature refers to the M12's ability to detect the impedance of headphones when they're plugged in and automatically set the gain to the appropriate value. With low-impedance headphones, the M12 switches to low gain, and the Gain LED glows green. With high-impedance headphones, like my Sennheiser HD 650, the M12 switches to high gain and the LED glows red.

D/A conversion is performed with an ESS ES9281AC DAC chip. According to the chip's datasheet, it works with 16-, 24-, and 32-bit PCM data sampled at all rates from 44.1 to 768kHz—the M12's specifications say 384kHz—and with DSD data from DSD64 to DSD256. The data status LED illuminates green for PCM data, red for DSD data. The M12 can also work as an MQA renderer, performing the final unfold of MQA data when fed from an MQA-compatible source that performs the first unfold. The status LED glows magenta with MQA data.


The M12 can be used with computers, of course; no special driver is required with MacOS and Windows 10 v.18.3 and above. It also works with tablets and smartphones and is compatible with iOS and Android 5.1 and above. Included in the box are two adapter cables: one USB-C–USB-A cable to use with computers, and one USB-C–USB-C cable for use with devices running Android. Those who wish to use the Questyle with an iOS device will need to purchase a USB-C–Lightning adapter cable with an OTG ("On the Go") interface. According to Questyle, the M12's Torex DC/DC converter combines high efficiency with low power consumption to maximize smartphone battery life.

I had been impressed by the sound quality on offer from Questyle's QP1R hi-rez portable player, which I reviewed in December 2015, so I looked forward to what I was going to hear from the M12. Using the USB-C–USB-A cable, I plugged the M12 into one of the USB ports on my late 2014 Mac mini and plugged in a pair of AudioQuest NightHawk headphones. The Questyle's Gain LED glowed green—as expected, since the NightHawks have an impedance of 23 ohms. The Roon app didn't recognize the M12 but did identify it as an ALSA device. I selected the M12 as a playback zone and set it to receive DSD data over PCM (DoP), to render MQA files, and to allow its volume to be adjusted with Roon. Then I started playing music.


The first piece I played was Antony Michaelson's 2003 performance of the Mozart Clarinet Concerto (16/44.1 ALAC file, Musical Fidelity Recordings), recorded by Tony Faulkner in London's Henry Wood Hall, which I produced. The image of the clarinet was clean and clear, with the orchestra unambiguously presented to the sides and behind. The low strings in the orchestra were warm sounding, perhaps a bit too much so. I played Pat Martino's Live at Yoshi's (16/44.1 FLAC, Blue Note/Tidal). This was a recommendation from Sasha Matson when we were discussing guitarist Martino's passing last November. Martino is joined on this album by Billy Hart on drums and Joey DeFrancesco on Hammond B3 organ, and the bass lines, played by DeFrancesco on the organ pedals, were somewhat loose-sounding.

I replaced the AudioQuests with Sennheiser HD 650s, which have an impedance that varies between 300 ohms and 500 ohms. The Gain LED glowed red, and as I started playing Live at Yoshi's the instruments were confined to the center of my head—mono! The Sennheiser cable was terminated with a ¼" plug, and I was using a generic ¼"–3.5mm adapter cable. I fiddled with the 3.5mm plug in the M12's jack, and mono turned to stereo. The Hammond organ's bass pedals now had a better balance between low-frequency weight and control than they had with the NightHawks.

I replaced the Sennheisers with the Audeze LCD-Xes that I had purchased after my review in March 2014. The Audezes have an impedance of 22 ohms. The M12's Gain LED turned from red to green, and I had no connection problems with the 3.5mm plug on the Nordost Heimdall cable that I was using with these headphones. The M12 did a good job controlling both the Hammond's bass pedals with these 'phones and the orchestra's low strings in my Mozart recording.


Streaming the Martino album reminded me that Billy Hart had played drums on the first multitrack digital recording I had made: pianist Marc Copland's quartet with guitarist John Abercrombie and bassist Peter Herbert, and Hart, at a private concert for the Santa Fe Chamber Music Festival in 1997. The late Wes Phillips, who had been at the concert, described Hart as about the quietest drummer he'd ever heard. Hart "uses silence in large blocks," he once wrote, explaining that Hart's playing featured a very wide dynamic range. I didn't use any compression in mixing this recording, so it was a good test of the M12's ability to preserve low-level detail while at the same time handling the high-level peaks.


Hart starts Copland's "Billy's Bounce" (16/44.1 ALAC file, unreleased) with a quiet dotted pattern on snare and hi-hat but gradually increases the complexity of the accompaniment, exploring the different textures of his ride and crash cymbals as first Abercrombie then Copland take solos. When Hart takes his own solo, the sounds of the toms, snare drum, and kickdrum were well-differentiated. The final rimshots on the snare almost took my head off when, seduced by the clarity, I set the M12's volume to "100"!

The M12 handled DSD data with aplomb. An album I have mentioned several times in my reviews is violinist Christian Tetzlaff and pianist Lars Vogt's superbly idiomatic performances of the Brahms Violin Sonatas (DSD128 files, Ondine ODE1284-2D/HDtracks), especially the first sonata. Pressing "Play" in Roon turned the data status LED red, and the violin sounded appropriately delicate and the piano suitably majestic when required, both instruments suspended in a subtle ambient halo.

Questyle Audio Technology Co., Ltd.
US distributor: Bluebird Music Ltd.
1100 Military Rd.
Kenmore, NY 14217
(416) 638-8207

Robin Landseadel's picture

" . . . And before the objectivists among the magazine's readers demand that my license to review audio components be rescinded . . ."

Worth it for that line all by itself.

Also wonderful to have a review, with measurements, of an inexpensive but potentially useful gizmo such as this.

I say the objectionists should renew the license with a warning concerning the use of florid subjective terminology. ;)

Jack L's picture


When we are on dongles, why comes in objectionists licensing ????????

Jack L

Archimago's picture

"And before the objectivists among the magazine's readers demand that my license to review audio components be rescinded, both Kal Rubinson and Jon Iverson, neither of whom is a dyed-in-the-wool subjectivist, reported hearing similar improvements with the original JitterBug and their reference DACs."

I dunno, John. I somehow don't think objectivist put too much stock in names of people. Nor does anyone care to rescind nor issue any licenses. ;-)

Lots of people hear all kinds of things all the time; it's a free Internet (for now) so people can say whatever, right?

IMO, as far as I could tell, the JitterBug FMJ did nothing. And the DragonFly Cobalt was not as good as the Red objectively or subjectively especially given the price increase.

hb72's picture

Have used the Jitterbug in my system in different configurations, from PCs into DAC, from an iPad into a DAC, from a dedicated streamer bridge into a DAC and the improvements were in all cases quite remarkable, consisting of way smoother treble, more musicality (ya, that is difficult to describe) and also better deep bass (more weighty bass drum, well defined upright bass) overall improvements, people often attribute to the term "analog".

teched58's picture

"And before the objectivists among the magazine's readers demand that my license to review audio components be rescinded, both Kal Rubinson and Jon Iverson, neither of whom is a dyed-in-the-wool subjectivist, reported hearing similar improvements with the original JitterBug and their reference DACs."

Much as many/most/I value JA1 as the last bulwark against b.s., the above quote (which Archimago first cited in his comment above) constitutes little more than a preemptive "appeal to authority" argument. JA1, with his background in science and deep and impressive history in quantitative measurement of audio equipment, knows better.

ms142's picture

I think JA1 was not appealing to authority, but appealing to sample size: Three independent error-prone measurements of something confirming the same result is stronger than a single one, however error-prone they may be. Say each objective-minded reviewer has a chance of 60% of hearing something that doesn't exist, and the chance they all hear something that doesn't exist is 21.6%, leaving us almost 80% confidence that there is something real. Of course this argument also requires that the readers trust the reviewers in reporting their impression honestly and independently, but JA1 naturally assumes that as well. (I'm saying this as someone who heard no benefits from Jitterbug)

Jack L's picture


There are quite a few similar "dongles" available in the marketplace.

In fact is offering something functinally pretty similar:

"USB C to 3.5mm Audio Adapter and Charger Type C to 3.5mm Headphone Jack Hi-Res DAC Dongle with PD 60W Fast Charging Support Lossless Music for iPad Pro/MacBook Air/Pro." Made in where else ? China, of course.

How much? USD18.99 a piece.

For portability alone, it worths every penny ! Why spend more for music to go???

Jack L

remlab's picture

Let me whip out my dongle, or do you want to listen to my big 10" record?

Jack L's picture


How about my 1,000+ vinyl LPs ? Bigger than yr "big 10" record", right ?

Jack L

remlab's picture


tonykaz's picture

... an improved Dragonfly from Mr.Rankin and Audioquest. ( which are made here in the USA ) Hmm.

but :

This little thing does MQA and DSD !

and :

It's got the Premier all time Greatest of all Audio Journalists reviewing it and say'n nice things about it. Phew!

In an iPhone dominated World, this thing should've been on the Front Cover of the Mag. , especially considering the Graying of our Audiophiles and our desperate need to attract "fresh blood" !

I like the Audioquest Dragonfly enough to give them as Gifts to family and friends, now I'll have to consider this cute little thing.

It's an exciting world we live in, an entire Hi-Fi system in the palm of your hand!

Thank you Mr.JA

Tony in Florida

Automat's picture

Hi John, thanks for the review. But as I didn’t read anywhere in your review which firmware you were using, I thought it won’t hurt to ask. There are two firmwares. An older one (M12 fw0.1.8463.rom) and a newer one (M12 fw0.1.8587.rom) as seen on the website of Questyle.
Please do check if you have the new one installed (I didn’t when purchasing the M12).
The new one is absent of the slightly rolled off treble. Also sounds a tad better in dynamics and Stereo image IMO. Please let us know which fw you used when writing your review.

John Atkinson's picture
Automat wrote:
Hi John, thanks for the review. But as I didn’t read anywhere in your review which firmware you were using, I thought it won’t hurt to ask. There are two firmwares. An older one (M12 fw0.1.8463.rom) and a newer one (M12 fw0.1.8587.rom) as seen on the website of Questyle.

I didn't check which firmware was installed when I reviewed the M12. But as the review sample was sent to me last August, I suspect it had the older firmware installed.

John Atkinson
Technical Editor, Stereophile

Automat's picture

Thanks. Well, if you still have your review example, it would be great if you could update the M12 and add a few „update“ sentences. Anyways, thanks for your words and thoughts!

Mark Tarone's picture

Great to see Stereophile shining a spotlight on Questyle's M12 DAC / headphone amplifier. I've owned the M12 for a few months now and love it. I like it far more than Audioquest's Dragonfly Black v1.5 which I've owned for years. Glad that Audioquest introduced this product type years ago and thrilled that Questyle has upped the ante at nearly the same price point.

As far as the M12, the #1 word that repeatedly comes to mind is musicality, closely followed by transparency and sound stage. The M13 engages me. It draws me in, and I thoroughly enjoy all that it illuminates. I also appreciate that it uses external cables (theoretically, inexpensive to replace if a cable fails) and comes with both USB A and USB C cables.

I want to buy a second unit to replace my Dragonfly Black v1.5.

Jack L's picture


Glad you are so happy with M12 digital sound for $139 !

Too bad my critical ears can't tolerate any sound digital when compared to vinyl analogue at home for much much higher cost for sure.

Yet for strictly killing time while travelling, a USB dongle + earbuds is the music-way-to go! That being the case, I would save even much more to get one from for $18.99. Why bother to pay more ???

Jack L

tincanfury's picture

Sounds great, but where can I buy it? The Where To Buy link on their website takes me to a Chinese retailed that doesn't seem to carry the M12.

vgizzi's picture

Can’t imagine trying to get all the components to work together without an arsenal of accessories and an engineering degree.

monetschemist's picture

Listening to my brand-new M12 plugged into my System76 Gazelle running Ubuntu 21.10. Headphones are HiFiMan 4xx. I like what I hear; I haven't tried comparisons yet (neither with my other DACs nor with my Sennheiser 6xx), but every so often something grabs my attention (drums on Oliver Mtukudzi's Ndima Ndapedza, notably punchy and crisp; some thunderous base on Nym's Eyeshine; a lot of texture and detail to the synth bass in Rara Avis' Medicine; and so on).

John Atkinson's review came through at the perfect moment, since the USB micro connector on my Schiit Fulla 2 is getting too intermittent, and I'm getting ready to travel again (yay!).

To the person above who wondered where you can purchase the M12 - I got mine through Amazon.

The M12 was easy to configure in Ubuntu Linux, to use the hardware interface and push the system mixing stuff out of the way. Verified that it's playing 96/24 on a Nils Frahm track.

Thanks for this informative review of a nice, reasonably priced and super portable DAC!

Matt_ISO's picture

Question, based on these measurements, the Questyle M12 should be able to output max level (2V) to an external amplifier with a load of about 2k, without clipping and maintain a Harmonic Distortion level of -110dB (0.0003%) right?