Forbes Review: Questyle M12 Mobile Headphone Amp With DAC Delivers On

From f orbes.com by Brad Moon

If you listen to music on your phone using wireless earbuds or headphones, you can probably skip this review. However, if you still physically plug into your phone to get the best possible quality out of the audio, then you are going to be interested in the Questyle M12. This is an ultra-compact, mobile headphone amp aimed at making your headphones sound even better. Perhaps more importantly, the Questyle M12’s integrated DAC is superior to the one in your phone. That means you can enjoy the high resolution lossless audio that streaming music services like Apple Music and Amazon Music HD are now offering.

Unboxing and First Impressions

The Questyle M12 headphone amp is dwarfed by the small box it comes in.

The Questyle M12 makes a great first impression. The mobile headphone amp is tiny. Thumb drive-size tiny. If having a wire plugged into your phone doesn’t bother you, I doubt you’re going to be put out by having the M12 added to the mix. The two ends of the M12 handle the input-output duty, so it is part of a daisy chain. Your headphones plug into the 3.5mm audio output jack on one end. The other end is a USB-C port. It connects to your device (smartphone, tablet, laptop, or whatever) for audio input and power.

Questyle M12 headphone amp and DAC review

CNC machined, anodized aluminum with 3.5mm jack on one end and USB-C on the other.

The amplifier is not just tiny and capable, it’s also attractive. Housed in an anodized aluminum shell, you have a choice of a black or silver finish.

There are tiny LED indictor lights that glow if MQA (Master Quality Authenticated) files are being processed, and to show whether it is operating with low gain or high gain output — the amp automatically adjusts that setting based on your headphones.

Questyle M12 headphone amp and DAC review

The M12 compared to AA battery.

Questyle includes several USB-C cables in the box, however if you’re an iPhone user you’ll want to spring for the optional USB-C to Lighting cable. I did try Apple’s own USB-C to Lightning cable and could not get it to work...

Two cables are included for Android and PC use, but iOS users will need to buy a Lighting to USB-C

Wired Headphones Sound Better

Bluetooth wireless headphones are great for listening to music without the hassle of a wire. However, those who are serious about the experience know that bringing the wire back into the equation improves the sound quality.

I found that adding the Questyle M12 headphone amp to the equation could make a difference in making the audio sound even better. I tested with a pair of Dali IO6 headphones (they’re wireless but can be connected using a wire), a great set of headphones that made my 2020 music lover gift guide, and a pair of Audeze LCD-1 Planar Magnetic headphones that Forbes contributor Mark Sparrow reviewed last summer.

Questyle M12 headphone amplifier in action.

The difference was subtle — more defined bass and music that could be played at higher volumes without distorting — but it was there. These are both low impedance headphones, so the M12 wouldn’t be working as hard. If you plugged in a pair of high impedance headphones (these push the capabilities of a phone), the amplifier would make an even more noticeable difference.

I should be clear here that if you plug in a basic set of headphones like the $59 specials flooding Amazon, you’re not going to notice any difference. A headphone amp isn’t a magic box and an improved audio signal can’t overcome the limitations of inexpensive drivers.

Hi-Res Lossless Audio Support

The real win for me came when I tried out Apple Music’s new Hi-Res Lossless option. These tracks are encoded at a maximum resolution of 24-bit/192 kHz. However, if you tried to listen to these tracks even with Apple’s AirPods Max using a wired connection, you’ll see a disappointing message on your iPhone.

What you'll see on an iPhone when you try to play Hi-Res Lossless music.

Apple says the DAC in its iPhone and iPad models can support a maximum audio resolution of 48 kHz. You can stream that music as Hi-Res Lossless, but you’re not going to actually be hearing it on your headphones, no matter how good they are.

However, the Questyle M12’s integrated DAC can decode files up to PCM 384kHz/32bit and DSD256. Plug your headphones in, and you can enjoy all the Hi-Res Lossless audio goodness. This is where I really noticed the difference. In general, that meant a big boost in detail and improved separation. With the Audeze headphones, the planar drivers responded with even more impressive bass. In short, Hi-Res Lossless audio is the gold standard in streaming music, and the Questyle M12 lets you to take advantage of it with your headphones — even though your smartphone’s DAC is incapable of supporting that resolution for output.

Again, you’ll need a decent pair of headphones to appreciate the Hi-Res Lossless audio upgrade.

Questyle M12 Key Specs:

Frequency Response: ±0.1dB (20Hz-20kHz)
THD: 0.0003%
Impedance smart detection (8Ω to 600Ω) and self-adjusting Gain
DAC (ESS flagship USB DAC chip ES9281AC) supports 32kHz – 384kHz (16/24/32Bit)
MQA Renderer technology
2.0 x 0.65 x 0.32-inches
CNC machined anodized aluminum in Classic Black or Stylish Silver
Includes USB-C to USB-C and USB-C to USB Type A cables
Supports Android 5.0 and above, iOS, macOS and Windows 10
MSRP $139.99

Questyle M12 Recommendation

Questyle M12 mobile headphone amplifier making Audeze LCD-1 wired headphones sound even better.

If you’re the type of person who is willing to physically connect your headphones to your phone to enjoy the best possible music-listening experience, you’ll want to check out the Questyle M12. The amplifier makes the most of your headphones’ capabilities. And with its integrated DAC — which is far more capable than the one built into your phone — you’ll actually be able to take full advantage of the Hi-Res Lossless audio that streaming services like Apple Music are now offering. Not bad for a device the size of a thumb drive.