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Pocnetwork Review: Questyle M15 Mobile Lossless DAC with Headphone Amplifier (Review)

Pocnetwork Review: Questyle M15 Mobile Lossless DAC with Headphone Amplifier (Review)

From By Ryan

Questyle has struck again with a fascinating headphone DAC solution for mobile devices. This one is dedicated a little further to the audiophile crowd than its last model. Providing a powerful solution within the space of a small thumb drive and likely giving companies like Audioquest something to worry about. It is the Questyle M15 Mobile Lossless DAC with Headphone Amplifier.

The company took a different route to the design by providing a glass window on top that allows the user to spy on everything going on inside. You can appreciate the detail that went into the development of the board and everything attached/soldered to it.

Being as small as a thumb drive, you can easily carry it with you anywhere without worrying about it taking up too much space. It is also only 1 oz in weight, therefore you won’t even notice that its there. Let it be in your pocket, or carefully tucked away into a slot within your bag, backpack, or anything else you use to carry your day’s necessities.

Beyond the glass window, the rest of the body is made from aluminum, providing a durable enclosure for everything in side.

It features a USB-C port and two cables for connecting it to your preferred mobile device. These cables include a USB-C to USB-C and a USB-C to USB(A). There is an option for USB-C to Lightning (OTG cable) as well, but that would be an additional purchase from the company unless you already have one.

This also means that it won’t work with anything that doesn’t have a USB port, so this is something to keep in mind. That being said, every modern computer, laptop, tablet, or smartphone, supports USB in one form or another (direct or adapted). So you should be fine.

You have the option of using a regular 3.5mm connection for headphones, or a balanced 4.4mm connection if you have a cable that supports it (and a pair of headphones that pairs to the cable properly). Like this one from Meze Audio, made for its 99 Series headphones. Or, a 4.4mm to XLR, 4.4mm to RCA, etc.

The side features a low/high gain switch. This is used based on the headphones or speakers you have connected to the DAC. If you are using headphones, you will likely keep the switch in the “low” position in most cases. With the exception of high-impedance headphones (250+, for example), where you would then switch it to “high”. You may also do the same when connecting it to speakers as well. You’ll know pretty quickly if it needs to be switched to high or not depending on the amount of volume you are getting.

Questyle M15 - LED Legend

There are two LED lights that can be seen through the window. One represents the gain of low or high (green or red) while the other represents the quality of audio it is getting from your device (data).

If you are playing back an MP3 or any other general format, the data light will likely be green. As you can see in the above image, this represents any signal that is 48kHz or less. So this includes things like Pandora, Youtube, or any other general everyday stream or format.

However, if you start playing a hi-res FLAC (note, just because something is in FLAC [or similar]format, it doesn’t mean it is hi-res) or similar format, the light will likely turn red, showing that it is getting hi-res lossless audio from your device.

If you are playing a source that supports MQA (ie, Tidal or playing MQA files through something like the USB Audio Player PRO app within Android), the data LED will periodically show as magenta.


The M15 offers four CMA amp engines, including an ESS ES9281AC DAC chip. You also get an ultra-low noise floor of -130dB or less, leading to a clean listening experience. So how does all of this translate to your ears?

This, of course, depends on what you pair it with headphone or speaker-wise. Obviously, if you are going to go through all of this trouble, you are going to want to use something formidable. In our case, we paired it with a number of headphones. Some benefited greatly, while others didn’t gain much.

This is a powerful amp, so it should be able to drive almost (almost) anything you throw at it. So we went straight to the pair we figured it would hit a wall with. This was the Beyerdynamic DT 880 SE Premium 600 Ohm Semi-Open Over-Ear Headphones. It takes a lot to feed this model with enough of an impression, so many mobile DACs fail at this one. Surprisingly, though, it was able to get a noticeable amount of volume from the headphones. Sadly, it didn’t leave a lasting impression, but it did (at least) get a decent amount of volume. It was an unfair pairing but still worth a try (and it did try).

We then paired it against the Meze Audio 99 Classic headphones. This ended up being one of our favorite pairings with this DAC. Everything came together nicely, with plenty of volume and range to go around. The resulting audio was fantastic.

That led to us spending hours rotating between various headphones from companies like Beyerdynamic, Creative, Sennheiser, Audeze, Audio-Technica, and more. Truly becoming one of our favorite portable DAC options out there within this footprint.

All music we tested it with included MQA, FLAC, or better. Albums from artists like Beck, Yes, Rush, and Pink Floyd really came to life (for such a small DAC, at least). Everything crisp, clean, and had plenty of detail.

Our Conclusion

This is indeed a formidable portable solution that provides quality competition when it comes to options like the Dragonfly Red. Many companies are going to have to step up with improvements to try to show up this one as you currently get much better without going with something that has a larger footprint and price.

We had a lot of fun pairing this with various headphone models and could easily see using this as a playback source with audio/sound consoles for live events. Especially, since it can fit so easily just about anywhere (during travel) without having to worry about added bulk.

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