At a glance
Expert evaluation
Strong Points
- Amazingly transparent sound
- Balanced and unbalanced headphone jack
- Switch for driving low impedance or high impedance headphones
- You can see the internal electronics of the M15 from the glass window
Disadvantages
- Get a lot of power from your phone’s battery
- Provides less stream quality details than competitors
Our verdict
High-performance DACs are essential for high-resolution music streaming, and the Questionyle M15 offers outstanding quality at a lower price than competing products.
Price at the time of review
$ 249.00
Best Price Today: Questyle M15 Mobile DAC and Headphone Amplifier
$ 249.00
A DAC is a device that takes over the audio conversion from digital to analog from mobile phones, tablets, or computers. Great sounds like the Questyle M15 reviewed here produce sounds that are orders of magnitude better than what an iPhone or Android device can offer on its own.
However, there are trade-offs. The portable DAC / amplifier combination adds devices, certain adapter cables, and wired headphones, which inevitably complicates streamlined everyday carrying. Why do you care about that? Bluetooth has no bandwidth to deliver a true lossless high resolution stream. Less than that is a compromise.
The Questyle M15 has jacks for both 3.5mm and 4.4mm headphones.
James Barbour / Foundry
It trades off wireless headphones. If you’re listening to an irreversible stream from Spotify and you like what you hear, there’s no reason to investigate the investment and hassle of a dedicated DAC. This does not mean that a good DAC will not improve the quality of the lossy stream, but it will spend a lot of firepower on the limited improvements possible.
When you reach the lowest quality lossless (also known as “CD quality”) streaming available from streamers such as Apple Music, Tidal, and Qobuz, the calculations change a bit. Most wireless Bluetooth headphone users can easily hear the difference between a lossy stream from a lossy stream from Spotify or YouTube Music Premium. And the gap between Bluetooth and DAC listening becomes even more pronounced at this level.
It’s the high-resolution audio tracks included in your Apple or Amazon music subscription, or the higher layers offered by Qobuz or Tidal that really start to hear the difference. There, the dedicated DAC begins to shine. You will not be able to hear the details available from these masters unless you are using a dedicated DAC.
What components does Questyle M15 include?
Questyle M15 is very easy to use. Once connected to the source device and connected to the selected headphones, there is only a gain switch to set the M15 to work with low impedance or high impedance headphones. There are two jacks, one for 3.5mm unbalanced and the other for 4.4mm balanced headphones.
The window on the back of the Questyle M15 allows you to color code your electronic components and circuits.
James Barbour / Foundry
The Questyle M15 measures 2.43 x 1.07 x .5 inches D (LxWxH) and weighs about an ounce, about the same size as a chewing gum pack. Its machined aluminum housing gives a profound feeling to something very small and light.
Questyle has chosen to build the M15 using the ESS ES9281AC DAC. It can decode a wide range of formats, including 44.1, 48, 88.2, 96, 176.4-, 192 16-bit, 24-bit, or 32-bit files. , 352.8- or 384kHz. The M15 can also handle DSD256 and fully supports ALAC, FLAC, and other lossless formats. You can also render an MQA stream.
You will see two lights on the board of your device. The switch on the left lights green when the Questyle M15 gain switch is set low and red when it is set high. The other light turns green if the sample rate is below 48kHz, red for high resolution lossless files, and magenta if the M15 is performing the final expansion of the MQA stream.
The Questyle M15 has a light that indicates the resolution of your streaming music source.
James Barbour / Foundry
This is less specific than the details you get from the more expensive AudioQuest Dragonfly Cobalt or iFiGO Bar dongle. If you’re obsessed with knowing exactly what signal is coming from your source device, there are other options to consider.
The Questyle M15 comes with a USB C-USB C connector cable for today’s Android, laptop, and iPad Pro devices. The USB C-to-USB A cable is provided for use with older computers.
Apple users purchasing from Questyle are advised to include an additional iOS adapter for an additional $ 20. One of the great pleasures of using the M15 on the iPhone is its slim profile, which eliminates the need to use the Apple Lightning to USB 3 camera adapter needed for AudioQuest’s excellent Dragonfly DAC and headphone amp combo.
The device comes with a drawstring bag, but if you want to protect the finish of the M15, we recommend adding a black, brown, or red leather case. Purchased directly from Questyle, it’s available as a $ 25 add-on.
The Questyle M15 has optional black, brown and red cases.
James Barbour / Foundry
Listen to Questyle M15
I tested the Questyle M15 on my iPhone using a USB C-to-Lightning adapter sold by Questyle. I listened to it with Focal Celestee headphones, Periodic Audio Carbon in-ear monitor, and Sony MDR-7506 headphones for less than $ 100.
A little doll babyThe new compilation by The Everly Brothers was released on Record Store Day’s Baby Blue Vinyl, but on Qobuz as a 192kHz high-resolution stream and on Apple Music as a high-resolution lossless Apple Digital Master. No matter how good your turntable setup is, it doesn’t provide the nuances and details you’ll hear “Cathy’s Clown” through the M15 and Carbon IEM. The sound is really great and is a testament to what you can achieve when you remaster a classic recording from the original tape.
The Questyle M15 comes with a USB C-to-USB C and USB C-to-USB A connector cable.
James Barbour / Foundry
Contemporary recordings like the new Perfume Genius album Ugly seasonStreaming at 96kHz on Qobuz may be even more impressive. Composer Mike Hadreas explores from high to low frequencies in ways that were not reproducible in the days of vinyl and CD. The exquisite details of these songs are only apparent when processed with a Questyle M15 or similar. Subsequent listening via Apple’s Lightning-to-headphone adapter is a massive comedown.
If you are a Tidal fan, the Questyle M15 does a great job with the MQA encoding of the service. Beyonce’s new single “Break My Soul” is streamed as an MQA master on Tidal, but just as a lossless track on Qobuz and Apple Music. The tide flow sounds much better than the other flows.
The Questyle M15 gain switch has both low impedance and high impedance headphone settings.
James Barbour / Foundry
Questyle M15 is perfect for critical listening
Not everyone hears the difference between lossless streaming and high-resolution streaming, but high-quality DACs are an essential purchase for anyone who can. If the difference doesn’t seem to matter to you, you only need a pair of Bluetooth receivers for your home system and good wireless headphones.
When investing in high quality wired headphones, the Questyle M15 provides incredibly detailed and neutral sound with little background noise. Its sound is comparable to AudioQuest’s flagship product, the Dragonfly Cobalt, and is about $ 80 cheaper before considering the adapters iPhone users need. If you’re looking to tackle high-definition audio, the Questionyle M15 is a great link to your wired audio chain.