Questyle M15 - the "Revealer"

 Questyle M15 - the “Revealer”

Introduction: 

Hello and mabuhay from the Philippines! Here we are for another audio gear review! And this time, a new kind of gear. A dongle! This will be my first attempt to review a dongle. If you have been around the audio community, you must have heard of AndyEF who initiated the Dongle madness. And what I have here is a top-tier dongle and I am quite blessed to have this as my first dongle. I am not as well-versed as Andy but I will try my very best to share my unbias and honest impressions here. 

Questyle is a company based in Shenzhen, China that specializes in quality amps. One of their product that is critically claimed by audiophiles is the CMA fifteen. This is my first encounter with them and I have not yet dived into their products. But by the looks of it, the company is low-key but makes exquisite and reference-grade releases. They don’t have a vast line-up but I think making it count is what matters to this company. Below is their website in English and feel free to roam around to know more about them. 

https://www.questyle.com/language/en/home/

Special mention: I would like to express my deepest gratitude to Zach from Questyle for entertaining my queries and being nice and generous to me. He is the Product Experience Manager over there. You da man Zach! 

With the M15, I would like to quote the concept of Questyle.

a time to reveal...

“In this complex world, we pursue simplicity.

The era of 5G has brought music streaming from smart devices fully into the mainstream. As more and more music platforms launch lossless audio streaming services, mobile hi-res audio has changed from a neat gimmick into a real and growingly popular way to enjoy high-fidelity music. However, it’s often impractical to use traditional HiFi audio equipment with your smartphone on-the-go, due to size and power consumption. To solve this problem, the M15 was born: it distills all of Questyle’s expertise and technologies into an amazingly powerful yet compact mobile DAC & amp.

Don’t be fooled by its small size. The M15 offers uncompromising performance and best-in class fidelity, giving you the ultimate portable audio experience.

Welcome to the world of truly mobile HiFi.”

Pros: 

• reference -grade sound quality

• Excellent price-performance ratio

• Appealing design and looks. The glass-way alone is a killer look.

• Bread and butter features

• Ground-breaking tech namely the CMA SiP modules that they have in their full-pledged amps

• Neutral sound signature with good dynamics and not sounding too clinical

• Enough power to drive full-pledge headphones as other reviewers claimed

• 3.5mm and 4.4mm outputs compare to M12 which has only 3.5mm

• Super low floor noise even on highly sensitive gears

• Direct compatibility for IOS devices which not all dongles possess (optional type-c to lighting cable can be purchased from Questyle)

• Physical gain switch (low and high gain)

• Superb performance in terms of technicalities (more of this later on)

Cons:

• Quite large in size for on-the-go setup

• No physical volume adjustment (subjective)

• The price can be steep for starting audiophiles. But hey, nobody said this hobby is cheap. The price is exactly $249. 

• Sound stage could have been wider (nitpicking) 

• Poor shielding causes interference aka EMI noise emitted from cellular data

DISCLAIMER:

My opinions here are entirely my own. Any form of incentive does NOT in any way influence me. This is purely my honest, subjective impressions and experience with the gear on hand. I cannot stress more that you should take this with a grain of salt for we have different perceptions to sound and what we hear. I always try my best to stick with the stock accessories that come with the gear by default. You are free to try other methods such as tip rolling or cable rolling. Below are worth noting before concluding on what I say here:

1. DAP (digital audio player, be it phone, laptop, mobile, or stationary setup)

2. DAC or dongle or any external amp

3. Ear Tips

4. Cables

5. Source of audio file be it offline FLACS or streaming services like Deezer, Apple Music, Tidal, Qobuz, Spotify, and the likes..

6. Your playlist. It matters and is worth considering when reading from a reviewer's perspective. It is apparent that you get to know your favorite reviewer and what they are listening to leisurely and critically. 

My reviews are more on how music sounds in my ears. I leave the technical stuff like frequency graphs and the physics behind the tech and drivers used to other reviewers.  

Specifications:

1.  DAC capability:

• PCM: 32khz - 384khz (16/24/32bit)

• DSD64 (1 bit 2.8mhz), DSD128 (1 bit 5.6mhz), DSD256 (1 bit 11.2mhz), MQA full decode

2. Output power:

• 3.5mm: RL=300ohms, Po=11.97mW, Volt (max) = 1.895 Vrms

• 4.4mm: RL=300ohms, Po=22.60mW, Volt (max) = 2.624 Vrms

3. Frequency response and THD:

• FR: +0.1db (20hz-20khz)

• THD + N: 0.0003%

4. DAC: ESS flagship USB DAC chip ES9281AC

Packaging:

The outer box gives a premium feel to it with a very minimal design yet elegant. The box has good corners. The inner box slides to the right and you are greeted by documentation with Questyle’s concept on the product (mentioned above) and product usage. Then a warranty card underneath. After that, the M15 itself was placed in the middle. Another layer is underneath where the 2 cables are. 1 x USB A to type C. 1 x type C to type C. Questyle took the liberty of being extra generous and sent me 1 x Lightning to type C cable making it possible to enjoy this on IOS devices. You can purchase this for an additional price as it is an optional inclusion. And another bonus from Questyle, they’ve included the leather protective case that they gave for free on promo in the month of May if I’m not mistaken. A red colorway was given to me. 

outer box

Documentations

optional inclusions

a Beauty of elegance

the cables

Physical attributes: 

The M15 is a unique-looking dongle. Oozing with elegance and sophistication. The look-thru glass gives it away. It is the only dongle I know of, that has this design. Let me show you all its physical attributes with photos.

Special note: The size of the M15 is quite large for a dongle and to be honest, it is not for an on-the-go setup. I can’t put it in my pocket along with my phone and it would be quite risky to let it hang with my phone, on commutes like the subway as the M15 has a decent weight to it. I’m the guy who moves around the house quite frequently and a lot of times I love doing my chores while listening to music. It is a struggle to move around with the M15 and I have to incorporate a belt bag to cater the M15 with my phone while doing my household chores like washing the dishes. Therefore, while the M15 still falls in the portable DAC category, I conclude it is still a semi-stationary setup with your phone. 

Features: 

The M15 has bread and butter features. It is not as fancy as other dongles with a screen where you can see the details of your track playing. But all the features that you need are here. 

One thing missing here that I personally prefer is a physical volume adjuster. This is a minor caveat for me, but I understand other individuals who strongly prefer having this. Connected with my LG V30 phone, I don't mind it that much because I still adjust the volume level with the physical buttons of my phone. But if it were to be adjusted via a slider on the screen, it would have been a bit of a hassle. 

A gain switch is present here. A very convenient feature. With my gears below 32 ohms, I use low gain, and for anything above 32 ohms, I use high gain. M15’s predecessor the M12 doesn’t have this feature. 

Available outputs are a single-ended 3.5mm, and a balanced 4.4mm. Another feature the M12 doesn’t have. If you have been an audiophile for quite some time, we all know balance output exhibits more out of your transducers and this will come in handy with your gears that offer balanced termination. 

Next are the light indications. There are two lights here. One indicates if you are on low or high gain. Green means low gain, and red means high gain. As for the other set of light, it indicates the quality or codec of the music you are feeding it. Green for anything below 48khz, red for anything hi-res, and magenta for full MQA encoding. 

And that’s it! Pretty basic right? But it’s all you need to enjoy your music with this dongle. No fancy screen here with sick transitions whatsoever. It emits a sense of being analog if you ask me. Which I am a fan of. Techs of the past and how they presented back in the days, appeal to me. And actually, it is easier to comprehend. Just look at the lights and you instantly know the quality of the file you are playing. 

Now moving on to how M15 performed on sound…

Sound impressions: 

Special Note: I’m a firm believer that source matters. A dongle enhances our listening experience because it is not integrated with the phone or laptop we are using as our source. It has an impact on the sound we hear but it is not the primary factor that alters what we hear. As an example, if you have a transducer with a slow driver performance, a dongle will not make the speed of that driver perform faster. Maybe it would be enhanced but in a very subtle way. The primary sound presentation still depends on the performance of the transducer. 

 IEMs used for the entirety of this review are the Seeaudio Bravery Red limited edition, Kinera Idun Golden 2.0, Bqeyz Topaz, and Autumn. More on pairings later on. 

I will have a different format here addressing my sound impressions with M15. I will not dissect each frequency but rather lay them down as a whole along with the technicalities. Just purely expressing what I hear and the changes I hear compare to my other setups. 

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Ok straight to the point. The M15 is a “revealer”. Period. It reveals a gear, in my case mostly IEMs, strengths, and weaknesses. It has a neutral sound signature to my ears and with stupendous resolving capability. Not limited to gears, M15 reveals properly and poorly mixed tracks. I can’t say if this is a blessing or a curse, but there are tracks that I enjoyed before, that I don’t enjoy that much now, all because M15 showed me that it is indeed a poorly mixed track. Though not the most powerful dongle in town, it can handle most IEMs and some M15 owners have claimed that it can drive some headphones. Well decently at least. I still have to venture into headphones territory to back this up, but I do have one. A Samson SR850 32 ohms, and I’m listening to it as we speak, and I’m around 70% level giving me a good listening level. 

The overall sound reproduction is crisp, transparent, and with brilliant transient speed. Neutral sources tend to be sterile and dry but M15 doesn’t present its sound this way. It remains organic, enjoyable, and with a wide dynamic range. 

Mids and vocals made the most distinguished mark on me. Lush, rich, and rendered with good emotion. I’m a passionate musician, and I like my music moving me to places when I listen to them. M15 never had shortcomings in this department. Instruments sounded the way they should be and never felt artificial nor unnatural. 

The lows are presented truthfully without any colorization with a snappy, and quick reproduction. I listen to a lot of jazz tracks, as I tend to look at how natural a gear can execute instruments in this genre and the lows are pinpoint. What you give the M15, it faithfully reproduces as natural and pure as it can. 

The trebles have a slight elevation as I critically listen. Some of my gears appear to have added shimmer and sparkle on top but not at the expense of being sibilant. 

The sound stage is above average. If I have to nitpick, it could use some extra expansion but negligible. I find my LG V30 via Hiby music app a bit ahead in terms of the sound stage but we’re talking minuscule difference here. 

Separation is spectacular and I can conclude that elements portrayed by M15 seems to be laid down with good spaces in between them. Hence making it very entertaining to listen to. I find joy in deciphering what each instrument is contributing to the whole piece when listening to my favorite jazz tracks and M15 delivered effortlessly. 

Imaging is brilliantly done as it places elements with accuracy. I can easily follow instruments let alone micro and macro details with good depth, width, and height as was intended by the engineers and producers.        

Resolution and detail retrieval is the pinnacle attribute of M15 as I clearly hear small details and texture of instruments. Guitars portray their string vibrations, pedal presses from piano players are brought to light, and vocal strains of singers can be heard, strikes of drum sticks and hand slaps of a percussion player are just a few to mention. There are many details here so be prepared to hear new elements from tracks you know too well.  

Performance: 

First off let’s start with the battery consumption of M15 with my phone. It is very energy efficient and doesn’t drain the hell out of my mobile phone. I mainly use the LG V30 for my offline flacs. I can enjoy a good 4 hours of playback and maybe even more if I’m not multitasking. This might be not enough for some but in my case, it is doable. If you prefer longer hours of playback, then a DAP will be more suitable for your needs. Or maybe a separate mobile phone solely for music playback will do. 

LG V30 quad dac x Hiby player music app

The performance of the M15 is very smooth here. The floor noise is clean as black. Integration with the app is flawless. The Hiby app easily recognizes the M15. I run with exclusive mode on. No popping sound whatsoever when changing tracks. This is my main setup for mobility and portability. 

Via UAPP:

Smoothly integrated as the Hiby music app. With UAPP I find the sound a bit brighter. User interface responsiveness is also slower than the Hiby music app. Well, we are not here to discuss and compare the two mentioned music player apps. Let’s just say I personally prefer the Hiby music app. Nonetheless, the performance of the M15 is the same with the said apps. 

Via Tidal on Android mobile phone:  

Still flawless and the app works with the M15 smoothly. Tidal Masters is indeed legit as the M15 emits a magenta led light when unfolding MQA. The Tidal app also offers an exclusive mode. Very handy. The app works with the M15 without any issues or hiccups. 

Via Apple Music on mobile phone: 

Here I encountered some issues. In particular with running on an Android phone. I can hear some popping sounds in the background. Very unnoticeable in playback, but you will notice it when you are not playing anything. And by a big margin, the output is much softer. A more enjoyable experience with this app is on an IOS device. With my iPhone 7 plus, the output is much more accurate and louder. I did not use an OTG for this connection as the lightning to type c USB cable was provided. This comes as an optional accessory if you were to purchase the M15. If you stream mainly with Apple music, do it on an IOS device. Strongly suggested.  

Via Macbook pro x Tidal:

This is my go-to stationary setup. Exclusive mode is also available as with the mobile version. When I’m in the mood to explore and discover new tracks, this is my favorite. If you are not a believer of MQA, there is also a bypass option to do that. One caveat is when I’m seeking (forward or backward) an evident popping sound is produced. Not a deal breaker, but I often seek within my tracks especially if I’m critically listening to some parts of a song. Integration of the app here on a Macbook pro with the M15 is also smooth and with almost no issues. 

Via Macbook pro x Foobar:

This is my setup to access my offline flacs on a stationary setup. UI of Foobar is very basic and navigation is quite a pain. I like keyboard shortcuts but with Foobar on a Mac, is very primitive. The trackpad or mouse will be your best friend as everything will be done with it. Playback and true encoding of your Hires files are legit. Volume control is handled by the Mac OS. The volume up and down is very convenient so no dragging of the volume slider here, which I personally hate and is cumbersome for me. Performance and integration are legit with this app. UI just needs to be updated. I am eyeing the Roon but I need to research more on this. 

3.5mm versus 4.4mm:

The performance of both outputs is actually decent and commendable. Both possess excellent outputs and there is no reason to discriminate the 3.5mm over the 4.4mm. Balanced output is balanced and better in terms of dynamics, loudness, technicalities, driving power, and overall sound presentation. If you have the means to plug into the 4.4mm, please do. Nonetheless, 3.5mm is still very capable and not to be looked down upon.  

Comparisons: 

I will mainly compare the M15 with my second source, the Hidizs ap80pro. This comparison is done with Kinera Idun Golden with the same song, approximately the same listening level, and on high gain mode since the Idun loves power. AP80pro running standalone, and the M15 is paired with an LG V30 android phone via the Hiby music app. Conducted both in 3.5mm single-ended output. 

Track: Fool Truth by UDD, a local artist from the Philippines, mix and mastered abroad. I know this track too well, so I picked it for this comparison. 

• The floor noise on the M15 is much lower than on the ap80pro.

• The ap80pro had more width, and the M15 had more height.

• Listening level concerning driving power. M15: 8/32 (25%) ap80pro: 43/100 (43%)

• The bass guitar in the intro is more textured and forward with the M15.

• Vocals are more forward with the M15, with more details like the singer's pronunciation. 

• Both exhibit neutral sound presentations.

• Drum kicks are punchier with the M15. 

• Vocal and instrument separation is better on the M15. 

Conclusively, the M15 performs better on technicalities compared to ap80pro. The sound signature is almost the same on both gears. The M15 has a more pronounced mid-bass. The M15 outperforms the ap80pro by a noticeable margin. Still, both gears are very capable and exceptional for reviewing gears. Almost to no colorization and alteration on sound. 

with the 4 horsemen

Pairings: 

With Kinera Idun Golden

Idun being a neutral set surprisingly paired well with the M15. I anticipated that this pairing will be too clinical or boring but that is not the case. The M15 brought the best out of the Idun, especially on technicalities. Not to mention the big improvement once used with the 4.4mm balanced output. This pairing is not void of being enjoyed particularly leaning towards the Hi-fidelity approach. Visit my full review of the Idun here: https://remedymusicaudiogears.blogspot.com/2022/07/kinera-idun-golden-20-my-sweet-prelude.html

With SeeAudio Bravery Red limited edition

The Bravery is a more engaging pair with the M15 than Idun. A more colorful sound signature but maturely tuned. With exceptional imaging and instrument placement, the M15 brought it to another level. A perfectly balanced pair that is hard to ignore and neglect. The Bravery opens up significantly with balanced output. If you have a 4.4mm termination, put it to good use right now. The Bravery is very easy to drive with an 18 ohms of impedance. You might want to switch to low gain mode to avoid distortions. 

Full review of the Bravery Red limited edition: https://remedymusicaudiogears.blogspot.com/2022/07/seeaudio-bravery-anniversary-limited.html

With Bqeyz Topaz

If you want to go warm, relaxed, and yet technically capable set, the Topaz is one of my favorite pairings. I was once on vacation, and I brought the Topaz with me forcing me to listen to it for a couple of days since I have no other IEMs with me, and this is the most organic and musical pairing in my collection. The neutrality and clinical nature of the M15 compliment the warm and lush sound of the Topaz. When I’m in the mood for just relaxed listening, this is my go-to pairing.

Full written review of the Bqeyz Topaz: https://remedymusicaudiogears.blogspot.com/2022/07/bqeyz-topaz-soft-and-tender-hum.html

With Bqeyz Autumn on neutral filters  

If I’m in the mood for that extra sound stage, I go for the Autumn. The wide stage of Autumn compliments the somewhat intimate stage presentation of the M15. As per the sound, the Autumn sits nicely in the middle of the three IEMs above. The most balanced pairing of all. The Autumn boasts its earbud-like sound stage. And I just can’t get enough of it with this pairing. 

Full and written review of Bqeyz Autumn: https://remedymusicaudiogears.blogspot.com/2022/08/bqeyz-autumn-game-changer.html

I have other IEMs in my collection, but these 4 will do as they are my most loved and “cannot live without” sets. All aspects above are very subjective. Please take it lightly with a grain of salt. Your mileage will most likely vary. 

Minor Issues:

As it breaks my heart to address some issues on an impressive gear, I still decided to include the following in this review. It has been a topic among us owners of the M15 at a thread at head-fi. It is regarding interference or what they call EMI noise. To be honest, I didn’t notice this until just recently. And yes the M15 emits a noise that is caused by cellular data from our phones. There are 2 ways to eliminate this. 

1. If your phone is connected to Wifi, you’re good. No interference. 

2. Turn on airplane mode.

The downside here is if you stream your music a lot, using cellular data, then you’re in trouble. Some owners are concluding that the M15 has poor shielding on interference from outside. Now even if I’m playing my offline flacs, but my cellular data is on, and not connected to a working Wifi,  yes I have the interference. I have an attitude of being a purist when it comes to my music, and I’m really downhearted to experience this. 

Personally, I mainly stream my music with Tidal on my laptop, and with this setup, fortunately, no EMI noise is audible. So for those who stream their music on the go, you might want to consider it first before pulling the trigger on the M15. But as I concluded in this review, the M15 is awkward to use on the go. So most likely, you will use the M15, on Wifi, streaming. You are safe if this is the case. Do be aware that the EMI noise is very minimal. It easily drowns out when you are playing your music. It’s just I’m a purist somehow, that knowing something is in the background, bothers me.

I would like Questyle to notice this issue, so they will consider it with their future releases, and potential successor of the M15. Questyle, please take this into consideration strongly. 

Verdict: 

The invasion of the dongles was mind-blowing in the audio community. I would like to commend AndyEF aka OspreyAndy for his #donglemadness for pointing me in the right direction. He saved me the trouble of going all through the almost hundred releases of dongles out there. 

 What caught my interest in the M15, to be honest, is its looks and design. Let us admit it, if it looks good, we hope it sounds good too. Apart from looking sleek, the M15 is my best experience in terms of source. My best one yet. I’m a technical-oriented listener, for the main reason that my main profession is being a pro-gigging musician. I always have a sweet spot for critical listening and I really have a high benchmark even if the sound is towards clinical presentation. But the M15 is not at all like that. It has rich dynamics, soul, and emotion portrayed character. It is just a very neutral and transparent sound presentation. 

Driving power is very decent although not the most powerful dongle in town. It is surely an upgrade from my Hidizs ap80pro. M15 at 25% listening level while the ap80pro at 43% listening level. Driving full-sized cans I still have to explore. I have an Audeze headphone on the way, maybe 2 weeks from now, and I will update this review once I pair the two. 

As for portability, I have some caveats on this. My listening setup with the M15 is somewhat a semi-stationary one. It is too large and heavy to be left hanging with my phone on commutes and is awkward to move with it while I’m moving around the house doing my daily routine and chores. It is not a true on-the-go setup in my case. 

Anyways I don’t want to repeat what I said in this review so I would advocate the M15 to those:

• Who prefers a neutral source

• Who has a priority on technical aspects

• Who loves critical listening 

• To reviewers who need to accurately judge gears

• To those who want to be rest assured that what they are hearing has no color added

• To those who want a resolving source

And that concludes my review of the M15! Again this is my best source yet! And as for reviewers who have more expensive source gears, they say that this punches way up to the caliber of 500$ price range sources. And you can enjoy that kind of quality for half the price! The M15 retails at 250$. I hope you enjoyed reading my impressions and a video version of this will be out soon. 

Special mention to Eric Lab for putting a good word for me with Questyle giving way to getting my hands on the M15. 

As always, love the music more than the gears! And your mileage may and most likely vary. Cheers, and catch you on the next one! 

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