Today we review the $249 USD Questyle M15 ultra-portable USB DAC/AMP dongle.
Disclaimer: Questyle sent us the M15 for this review. As always, I am here to share my honest opinion with you.
With over 10 years of experience in the Audio field, Questyle is dedicated to the research, design & development of high-performance audio equipment. They have vast expertise both on desktop and mobile units and they have designed multiple award-winning products throughout the years.
My encounter with Questyle dates back to 2015. They had released a portable player called QP1 and I was quite impressed by its performance. Today, we are going to be checking out Questyle’s latest mobile DAC/AMP dongle, the M15, together.
Questyle M15 – Portable USB DAC with Headphone Amplifier
The M series currently consists of 2 products. The M12 and the Questyle M15. The M12 is the first product of the series and was introduced in 2021.
Questyle used ESS’ 9281AC premium-tier chipset and a single module of their patented “Current Mode Amplification” technology. It also features a smart-impedance detection system, therefore adjusting the gain setting automatically. It has a straightforward and compact design.
Now that we are up to speed with what the M12 had offered, we can talk about the newest and latest. The M15 features the same premium-tier 9281AC chipset from ESS Technology. However, the M15 features not one but two patented “Current Mode Amplification” SiP modules. That is not the only hardware difference between the M12 and the M15. The M15 offers balanced circuitry and comes equipped with a gold-plated 4.4mm balanced HPO. The M12 retails for $139 USD whereas the new M15 costs $249 USD without the leather case and the lightning cable. The new M15 is available in major retailers such as Linsoul, worldwide, as well.
Here is a list of all the highlights and specifications of the M15.
DAC: ESS Technology ES9281AC
AMP: x2 CMA SiP Modules (four CMA amps in total)
Power: Gain L/H – 4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms,THD+N=0.00057% – TOREX Power Management
Decoding: PCM: 32kHz – 384kHz / DSD: DSD256
Headphone Out: 4.4mm BAL / 3.5mm UNBAL
Build: CNC Aluminum, Glass Front Cover
Packaging, Accessories & Design
Questyle is a company that attaches great importance to aesthetics. First off, I have to say that the M15’s presentation and overall unboxing experience feel pretty premium. The M15 comes in a small, drawer-style cardboard box. The packaging is quite compact and its design feels elegant. It gives off a luxurious bracelet packaging vibe and I really like it. Upon sliding the inner section of the cardboard, a wonderfully designed dongle greets you.
The M15 is one of the most impressively designed dongles I’ve seen in the last couple of years. Of course, design and aesthetics are subjective but as a tech enthusiast, I love see-through devices. Questyle nailed this design and you can see the whole PCB (which is very neat) through the top cover. The glass looks thick and tempered so I don’t think it would shatter easily.
There are two bright status LEDs on the audio board marked as DATA and GAIN. There are many impressive details such as the ESS logo, carefully picked, aesthetic 4.4mm socket housing, the twin AMP modules, and so on. It is obvious that Questyle also paid attention to the design aesthetics of the audio PCB, not just placing glass and making it a fait accompli. Furthermore, the rest of the device is made of aluminum and the chassis is CNC’d. The build quality is very impressive and I can easily say that this is the best-looking and best-feeling device I’ve held in my hands.
The accessories are under the foam compartment that holds the M15. The device comes with a short USB-C to USB-C cable and a short USB-A to USB-C cable. The cables are braided and in black color. The plugs feel durable and well-made. The cable jackets, on the other hand, are a bit stiff, not as flexible as the cables we’ve seen from other manufacturers. Additionally, you get a product manual and that’s all there is.
If you have the extra bucks for accessories, Questyle offers iOS cable for an extra 20 bucks and a leather case for another extra 25. I have the red leather case with me and quality-wise, it is really good. Personally, I took the liberty of cutting a generic phone screen protector and slapping it on the M15, and combining that with the chic leather case got me a fool-proof M15.
I can now carry it anywhere with me, with peace of mind. I believe Questyle could have included the leather case in the packaging since the pricing is rather on the higher side of the scale among dongles.
Overall, I am very happy with the design and overall aesthetics of the device. From the Questyle font on the back to the see-through front cover, the M15 is an absolute eye-pleaser. Great job, Questyle!
Controls & Ease of Use
The M15 is a pretty straightforward device. It works driverless with macOS and Windows 10+ computers, and Android and iOS smartphones. It is ready to go straight out of the box and requires no setup of any sort. Questyle regularly releases firmware updates for the M15. You can use this link to jump to the official downloads page.
The device comes with a two-step gain switch and that is it. There are no additional buttons, hardware volume control, or anything else on the chassis. Two status LEDs are present on the audio board, one for gain setting and one for data. Gain LED is color-coded so red is high gain and green is low gain.
Additionally, in order for PCs to utilize the M15, you must plug your headphones in. It has some sort of impedance detection system and it turns on power-saving mode automatically as soon as you unplug your earphones.
As for power management, the M15 does not drain my phone’s 5000 mAh battery any more than the other dongles we have reviewed. I haven’t experienced any issues with its power usage. Apparently, the CMA modules are efficient!
The M15 does not pick up RFI or other interference from the phone whether the phone is on 4,4.5 or 5g networks. If you remember, this was a huge issue with the original Chord Mojo a couple of years back. Questyle chose a thick aluminum chassis and a thick glass perhaps because of this. The PCB is well-shielded from external signals.
I see that Questyle is not completely transparent about the exact power delivery. I found the specification information given to consumers insufficient, its power at 16, 32, and 150 ohms is not clearly specified. The specs say that the unbalanced 3.5mm output is as follows: RL=300Ω,Po=11.97mW, Vout(Max)=1.895Vrms, THD+N=0.00045%.
Balanced output is higher and specs are as follows: 4.4mm:RL=300Ω,Po=22.60mW, Vout(Max)=2.624Vrms, THD+N=0.00057%. This means that the device is quite powerful, at least on paper, and I have done a couple of tests with 8-ohm IEMs and 150-ohm dynamic headphones.
I used Yanyin Canons for their ability to pick up background noise and hiss and I used my long-time favorite budget headphone, the 58X. The M15 is powerful, the 58X reaches my comfortable loudness level at just %40 volume. %60 and above is physically painful. The M15 has no trouble driving Hifiman’s HE-R9 to its limits as well.
Moving on to the sensitive IEMs, the Yanyin Canon reaches my comfortable loudness level at just %5 volume. There is no channel imbalance or background noise so M15 is silent. Yanyin Canon IEMs (8Ω) are quite picky about this and it is safe to say that M15 offers a pitch black background.
The review continues on Page Two, after the click HERE.
Page 2: Questyle M15 – Sound Quality, Technical Capability, vs. UA5, Last Words