For Sale Questyle Audio M15 Headphone Amplifier (with DAC)

Further Information

The M15 is a miniaturised on the go version of Questyle’s flagship Current Mode Headphone Dac/Amp circuitry… 

and honestly, it delivers nothing short of stupendous fidelity with drive power deceptively far beyond its size or specifications would suggest… proving than once again, current being to wattage what torque is to horsepower.

A great many reviews have attested to it’s astounding capabilities:

Questyle M15 Review (1) – Stellar By Starlight

https://www.audioreviews.org/questyle-m15-review/

Random User Comments:

“M15 doesn't sound like a dongle really. More like a mid high tier serious device. Questyle did an awesome job!”

“…. I didn't need another dongle, I was just curious about Questyle and this seemed like a cheap entry point to sample one of their devices.  I've been absolutely floored by it as an all-in-one USB desktop source.  

I have a Mojo 2, but sonically I prefer the M15.  I don't have expensive source equipment, I have an old reliable Zen DAC v1, an EF400, an Earmen Sparrow, and I have a Schiit Lyr3 and the Magni Piety from Niche.  

I prefer the character of the M15 to all of it.  The M15 to the Lyr3 takes a drier amp and makes it sound fluid and glassy.  

Previously I found ESS-based implementations to be a bit harsh, maybe brittle in the treble, sharp and clear no doubt but a bit too thin for my preference.  

The M15 (to my ear) extends cleanly in both the lows and highs, is surprising punchy even with some power hungry headphones like the Liric or t60rp Argons, and some high impedance stuff like my 300ohm ZMFs in the Eikon and Auteur Classics.  It's clean but full sounding, plenty wide, definitely "wet", I don't hear any dryness or grain.  

With the 109 Pro it is a near perfect pairing, one I struggle to imagine how it might be improved upon or beaten as a value proposition.  

I think you nail the highlights of the device in this review and admittedly I was very skeptical before I pulled the trigger.  It's one of the pound-for-pound best investments I've made in the hobby…”

“Reviewed this last year, it’s the best dongle under $500.

It won an award from my channel last year. I’ve still not found one that sounds as good it’s remarkable”

M15 Specs

The M15 contains two of Questyle’s patented CMA (Current Mode Amplification) SiP modules, for a total of four CMA amp engines. 

This quadruple drive amplification circuitry gives an outstandingly strong output that can drive almost any headphone. 

Questyle’s Current Mode Amplifiers are characterised by their small footprint, low voltage operation, and minimal power consumption. 

Current amplification has a naturally low impedance, affording the M15 a bandwidth up to 1MHz, distortion as low as 0.0003%, and the ability to reproduce every detail hidden deep within any track.

3.5mm TRS / 4.4mm TRRS outputs

With its four CMA amp circuits, the M15 supports both unbalanced (3.5mm TRS) and balanced (4.4mm TRRS) outputs.

It also has manual gain adjustment via the slider on the side, which makes it easy to choose high/low gain depending on the connected headphone, speaker, or HiFi system.

The M15 Connects you to the Streaming Era 

The M15 supports almost all music streaming platforms worldwide, including Apple Music, Tidal, QQ Music, among others. 

It fully supports and decodes ALAC, FLAC, MQA, and other lossless formats.

Unparalleled ease of use, Plug-and-Play

M15 is fully compatible with Android 5.1 and above systems on popular smart phones and tablets.
For PC, it supports Mac OS and Windows 10 version 18.3 and above with no additional driver installation required.

Output Interface

3.5mm standard headphone jack x1
4.4mm balanced headphone jack x1

Output Power

3.5mm:RL=300Ω,Po=11.97mW, Vout(Max)=1.895Vrms,THD+N=0.00045%
4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms,THD+N=0.00057%

Frequency Response & THD

Frequency Response:  ±0.1dB(20Hz-20kHz)
THD + N：0.0003%
DAC：ESS flagship USB DAC chip ES9281AC

DAC Capability

PCM：PCM: 32kHz – 384kHz (16/24/32Bit)
DSD： DSD64(1Bit 2.8MHz) , DSD128(1Bit 5.6MHz), DSD256(1Bit 11.2MHz)