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Questyle M15 Full Review

Introduction

In the era of smartphones and streaming services, having a quality portable DAC or amp has become essential for audiophiles who want great sound on the go. The Questyle M15 aims to deliver premium hi-fi performance in a compact and stylish package.

I’ve had the chance to extensively test out the M15 over the past few weeks across various setups. Read on for my comprehensive review covering all aspects of this impressive little device.

Disclaimer: This review reflects my honest opinions only. I haven’t received any compensation to influence my thoughts. All ratings consider the product’s price point.

Questyle M15

Image of Questyle M15 DAC And AMP (Image via linsoul.com)
Image of Questyle M15 DAC And AMP (Image via linsoul.com)

Specifications

  • Decoding Parameters: PCM 32-Bit/384kHz, DSD256
  • Output Interface: 3.5mm single-ended, 4.4mm balanced
  • Output Power(3.5mm): 11.97mW @ 300Ω, Vout(max): 1.895Vrms
  • Output Power(4.4mm): 22.60mW @ 300Ω, Vout(Max): 2.624Vrms
  • Frequency Response: 20Hz-20kHz±0.1dB
  • THD+N: 0.0003%
  • Dimensions: 61.8×27.2x12mm

Individual ratings

Build Quality

The M15 has a sleek metal chassis that feels sturdy and well-built. The transparent front panel is a unique and appealing design choice, though the protruding glass face makes it prone to scratches.

0/5
Technology

With the ESS ES9281AC DAC chip, the M15 can handle up to 32-bit/384kHz PCM, native DSD256, and full MQA decoding, providing excellent support for high-resolution lossless audio formats.

0/5
Sound Quality

The sound signature is clean, transparent, and accurate, with a slightly bright tilt. It offers punchy bass, airy highs, and natural mids, along with impressive technical performance in terms of imaging, separation, and retrieval of micro-details.

0/5
Power Output

While the M15 doesn't have extremely high power output on paper, its current mode amplification technology allows it to capably drive a wide range of headphones and IEMs, from moderately easy to drive to current-hungry planar models.

0/5
App Integration And Usage

The M15 works seamlessly across various sources, including Android devices and iPhones (with an adapter). It automatically switches between USB DAC and analog modes and doesn't require additional apps or drivers.

0/5
Unique Features

The M15 stands out with its current mode amplification technology, MQA full decoding, unique "look-through" design, and data rate indicator LEDs, offering both technical and aesthetic advantages over generic USB DACs and amps.

0/5

Overall Rating

0/5.0

Bottom Line

The Questyle M15 offers tremendous musicality in a seriously portable form factor. This stylish performer raises the bar for dongle DACs; demanding audiophiles should give it an audition to appreciate just how good your high-res music library can sound on the move.

Pros

  • Slick design with a transparent front panel
  • accurate, neutral, yet musical sound
  • black background and stellar technical performance 
  • handles high-res lossless and MQA decoding
  • efficient power delivery system
  • works seamlessly across sources.
  • great value at $249

Cons

  • No onboard volume buttons
  • Glass windows are prone to scratching.
  • less driving power than dedicated portable amps
  • Lightning adapter required for iPhones

1. Packaging

Image of Questyle M15 DAC And AMP (Image via linsoul.com)
Image of Questyle M15 DAC And AMP (Image via linsoul.com)
  • Questyle M15
  • cables
  • paperworks

2. Design And Build Quality

Right out of the box, the M15 makes a striking first impression. The sleek metal chassis feels sturdy, with a nice weight to it, instilling confidence that it can withstand daily use. 

But the highlight is undoubtedly the transparent front panel. This unique "look-through" glass window gives you a peek at the neatly arranged internal circuitry, consisting of the ES9281AC DAC chip, current-mode amp modules, and other components. It's geeky yet aesthetically pleasing.

The rest of the body is finished in a matte black hue, which resists fingerprints well. I'm thankful that Questyle includes a protective leather pouch because the protruding glass face risks getting scratched otherwise. 

Overall, the M15 seems thoughtfully designed, down to little touches like perfectly countersunk ports, a subtly glowing Questyle logo when powered on, and LEDs indicating the selected gain mode and incoming data rate.

3. Technology and Decoding Capabilities

At the heart of the M15 lies ESS Technology's flagship Sabre ES9281AC DAC chip. It's capable of resolving 32-bit/384kHz PCM and handling native DSD256 with full MQA decoding. This allows you to make the most of high-res lossless streams from services like Tidal, Qobuz, and Apple Music.

But DAC performance also depends greatly on the amplification and other implementation details, which is where Questyle flexes its engineering muscles. Their proprietary Current Mode Amplification (CMA) technology enables a miniature yet extremely accurate and dynamic amplification stage inside the M15.

You get twin independent CMA System in Package (SiP) modules, utilizing a total of 4 current-mode amp engines in a pure Class A configuration. This allows lower distortion and higher bandwidth compared to traditional voltage-mode amplifiers.

Furthermore, an onboard hardware gain switch lets you toggle between regular and high gain modes depending on the connected headphones. Balanced (4.4mm) and single-ended (3.5mm) outputs are provided.

4. Sound Quality

Image of Questyle M15 DAC And AMP
Image of Questyle M15 DAC And AMP

Tonally, the M15 delivers a clean, transparent, and accurate reproduction. The overall signature leans ever so slightly towards brightness rather than warmth, but avoids harshness or sibilance. 

Bass is punchy and extended with good slam, while highs have plenty of airy detail without fatigue over long listening sessions. Mids sound natural with no coloration; vocals are centered on intimacy; and guitars have a realistic bite. It is hard to find any faults here, as the M15 sounds pleasingly cohesive from top to bottom.

Technically, this unassuming dongle punches far above its size and price class! Imaging is precise with stellar instrument separation. Soundstage feels nicely open and spacious too, considering this form factor. Tracks with dense layering are handled with aplomb, helped by the low-noise floor and background.

Whether it's the textures of acoustic strings, room ambience cues, or barely audible background chatter in live tracks, the M15 retrieves micro-details effortlessly and immerses you right into recordings.

5. App Integration And Usage

The M15 plugs into phones or tablets via USB-C or Lightning ports, drawing power from the source device. It auto-switches between USB DAC and analog modes. I tested the unit with various Android devices using UAPP and Neutron players, as well as an iPhone with Apple Music.

In all cases, it functioned as expected without the need for extra apps or drivers. Do note that you'll have to control volume from the source itself, as the M15 lacks onboard buttons. I personally didn't find this a hassle during daily commute usage paired with my smartphone.

Battery life is quite impressive too, thanks to the efficient current-mode amplification. I easily got 5+ hours of continuous playback without fully draining my phone battery. The M15 itself doesn't heat up under sustained loads.

6. Unique Features

Image of Questyle M15 DAC And AMP (Image via linsoul.com)
Image of Questyle M15 DAC And AMP (Image via linsoul.com)

There are some clever touches that set the M15 apart from generic USB DACs and amps:

1. Current Mode Amplification: Delivers high fidelity, accuracy, and dynamics from the compact amplification stage

2. MQA Full Decode: Unfolds streams from Tidal Masters for bit-perfect output

3. Look-through Design: Offers a nerdy-chic view into the neatly arranged internals

4. Data Rate Indicator: LEDs flash different colors based on the audio data rate for PCM, DSD, or MQA streams.

8. Power Output and Drivability

Despite modest output power ratings on paper, the M15 can capably drive a wide variety of headphones and IEMs thanks to the current mode Amplification. Low-sensitivity cans shouldn't be an issue, provided their impedance isn't too low.

Anything from moderately easy-to-drive headphones like the AKG K701 to current-hungry planars such as Hifiman's Edition XS and Ananda presented no problems across a range of genres, either in balanced or single-ended modes.'

Harder-to-drive models may not reach their most dynamic potential, but they still sounded loud enough for enjoyable listening with headroom to spare. That's seriously impressive output for any dongle!

9. FAQs

Q. Who should buy the Questyle M15?

The M15 makes most sense if you:
Frequently listen to high-res Lossless or MQA music libraries on your smartphone.
Want nearly desktop-grade fidelity that travels lightly with your device?
Prefer a neutral, transparent, and technically precise sound.
appreciate good aesthetics complementing great engineering.

Q. Who should avoid the Questyle M15?

Those requiring: 
ultra-high driving power for very hard-to-drive headphones
warmer, more colored tonal balance
Basshead levels of thump and slam

Q. Does the M15 work directly with iPhones?

Yes, but you need Apple's Lightning to USB Adapter accessory for connectivity. Questyle optionally bundles a M15 to Lightning cable.

Q. How does the sound compare with dedicated DAPs?

The stunning resolving ability and amplification can give several midrange DAPs a run for their money. Of course, dedicated players still hold an edge in driving power and battery life.

Q. Any heating or interference issues?

No one has observed so far. The M15 runs cool under typical loads, and the noise floor is silent across all IEMs tested. It induces minimal battery drain as well, thanks to the efficiency of the amp stage.

Conclusion

The Questyle M15 punches far above what its compact dongle form factor and pricing suggests. This diminutive device produces a spacious, transparent, and tonally balanced presentation despite its size. 

For $249, it's hard to imagine getting more resolving power, amplification grunt, or premium hi-fi performance packed into a svelte 58 grams. And it looks downright sci-fi cool, too!

Clearly, this Current Mode Amplification business works sonic wonders, allowing Questyle to miniaturize high-fidelity playback that outclasses generic USB DACs and amps.

Become an audiophile pro! Master the key terms and discover the secrets of high-fidelity audio. Go to the Answers section to start your learning adventure.

Overall User Rating

4.5

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