Introduction to the Questyle M15 review
Questyle is a Chinese company that has been on the market for quite some time now. Unlike their other counterparts at the time, they always aimed at the premium market. Quality and performance, over low prices. One of the first purely Chinese companies that actually threw a challenge in the face of more established companies on the market. That is something to admire, as it was in complete opposition to what their competition was doing. There also is a more personal story that I have with Questyle.
I can remember the company appearing on the Polish market as I was learning the ropes of audio reviewing. I even listened to the CMA600i, I believe, but left the website before I got it in for a review. Guess, who later did that review. The one and only, Paweł from Ear-Fidelity. What makes it even funnier is that we actually didn’t know each other yet. He was my replacement when I left. Who’s that guy, with that ridiculous hairstyle? Somebody mentioned he looks like a pineapple. It lives rent-free in my head now.
Well, now we are good friends and today he’ll be at my 30th b-day party. Maybe I’ll buy him a pina colada… Small world, huh? It’s worth noting that the review was very favorable, and he even said it was one of the best devices available at the time. I’m not translating that directly from Polish, so let’s say you trust me on this one.
Questyle saw the rise of portable audio and the need for the best possible sound quality outside the home. That inspired them to create the subject of this review. The M15 is a portable Hi-Res DAC/AMP, a so-called dongle. It connects to your phone via a USB type C cable and allows you to utilize your IEMs and headphones on the go. Its goal is to combine Hi-Res audio, capable amplification, and premium build quality. Did they succeed? This review of Questyle M15 will tell you everything.
I’m fresh after doing the Andromeda Emerald Sea video (check it out on YouTube!), with its absolutely crazy packaging. Well, here we have the absolute opposite.
We only get the most basic box, holding essentials. In the box you’ll find: the dongle and the USB type C pigtail cable. Done. Whoa, reviewing the Questyle M15 is so easy.
The leather case is available separately for $25 in a couple of colors: black, red, ivory, green, brown and grey. I got the black one because it was the only one that I could grab locally, but bet your ass, that Ivory would look absolutely stunning.
Design and Build Quality
I have to say, that the reviewed M15 lives up to the “Questyle hype” from my memories. Seems that the company hasn’t strayed from those “ancient” times. The body is made out of milled aluminium and the top is made out of either acrylic or glass. It’s like a back window in a Lamborghini. It’s not for you to safely park backwards. It’s so you can see the engine! In this case, the electronics are on the display. Why can’t girls get me that aroused? Laser-engraved markings and text cover the whole device. You can see that it is not a cheap toy. Fitting is impeccable.
The user experience was really good, especially after I bought the leather case, and stopped worrying about scratching it so much. Still managed to get a tiny scratch on the glass, curious if you can spot it in the pictures.
The dongle has one neat function: when nothing is connected to the output, it turns off to conserve energy. My main issue with the reviewed Questyle M15 is the fact that it doesn’t have integrated volume control. You control the volume from your source. My Samsung S21 FE 5G has a ridiculously large step (something around 10%) which can’t be changed in the settings. I had to find a program called Sound Assistant that allowed me to change that and reduce the volume control steps. Besides that, using the Questyle M15 is great.
Tech inside the reviewed Questyle M15
The Questyle M15 features a couple of interesting solutions, which I’m more than happy to nerd out about.
Let’s start with the star of the show, the ESS Sabre ES9281AC codec. It’s an impressive IC, integrating a USB Audio interface, very good DAC, ADC, and some other features like output jack detection. How they managed to fit all that in such a small package is beyond me. It supports PCM 32bit/384kHz and DSD256.
On top of that, Questyle’s engineers implemented their flagship technology, the CMA (Current Mode Amplification) SiP headphone amplifiers. Four of them to be exact. Current mode amplification is not as popular as voltage mode amplification, but some manufacturers swear by it, including Accuphase. Current mode amplifiers are the most known for their speed, they can handle some very high-frequency signals.
The SiP has a bandwidth of 1 MHz with only 0,0003% distortion. Those are some nice numbers. What about the power? You won’t catch the reviewed Questyle M15 slacking. The official data shows 22,6mW @ 300 Ohm with no rating for the 32 Ohm load. Output voltages are rated at 3,5mm: 1,9V and 4,4mm: 2,6V. I know it’s hard to compare those numbers with other dongles. In my experience, the reviewed Questyle M15 is more powerful than I would ever need it to be, driving Meze 99 Classic and low-sensitivity IEMs with ease.
For our convenience, we can select gain, either low or high. I would prefer the low gain to be actually lower than it is. I still don’t have as much volume control over the Andromeda ES as I would like to. Also, the high gain is very high and even the headphones I tried didn’t need that much. The power supply used is named Torex and is focused on keeping the efficiency as high as possible.
I have to admit, that while on low gain the reviewed Questyle M15 uses minuscule amounts of energy. My phone is very happy about that. Not having to load your phone after a ride across the city is a nice feature. One last thing. The M15 has a rare tendency to pick up some interference while not playing. Like once a day. This doesn’t happen at all when listening to music, but c’mon Questyle.
Most of my testing was based on Campfire Audio Andromeda Emerald Sea and Unique Melody MEST. I have used Time Stream cable for the Andromeda and Erua Audio Tawa for the MEST. I tested driving capability on Meze 99 Classic (no issues) and HiFiMan Sundara Classic (didn’t work that well). Other IEMs used in testing: Letshuoer EJ07M, Craft Ears Aurum. Dongles used for comparison are listed later on. As usual, I’m using 4,4mm connections wherever possible.
Well to start off, no surprises here really. First of all, the sound quality is really high. Questyle is one of the brands I would consider a safe choice quality-wise. Secondly, it sounds like it has a Sabre chip. Incredible dynamics, powerful bass, good sound staging, clear-cut sound, and black, velvety background. It sounds like some of my other reviews, but it’s not my fault that ESS Sabre dominates the market. I’m aware of that, but not much I could do about it.
Okay, I have something new for you! The newest generation of Sabre DACs is not as fatiguing to me as the previous ones and that applies to the one used in the reviewed Questyle M15. They had to change something in the design. The tonal balance of the M15 is a bit boosted in the top and bottom ends. It builds extra excitement and increases the foot-tapping factor, but it may not be the best thing for studio usage. Let’s dive into more details.
The first thing I have noticed with the Andromeda is how well the Questyle M15 drives them. Zero noise, maximum dynamics. I was dumbfounded at what bass the ES started producing. Big, bold, with the punch of a martial artist. It is more snappy like a lightweight MMA, than a heavyweight boxer, but still.
Listen to Kanye West’s Black Skinhead, this song really benefits from the reviewed Questyle M15’s sound character. In the beginning, you get a heavy drum bass with some quick jumps left and right on the soundstage. Controlled aggression, lightning-fast transitions, and complete silence in between the sounds really took me off guard. It’s absolutely amazing how the Andromeda ES transformed under the M15’s iron grip. On the other hand, a bass line from Starlight, by Muse has incredible complexity to it.
It goes throughout the song, and you can try it as a reference for textures. It’s a big sound with lots of detail with drums on top of it all. It’s a great test for equipment and you can see how much control the Questyle M15 has when drums come in after the intro and the bass line doesn’t lose anything. I’m thoroughly impressed by the performance of the Questyle’s dongle.
The midrange is slightly recessed in comparison to other ranges, but it doesn’t lose its qualities. Great things are expected from dongles at this price point. Reviewed Questyle M15 delivers. One of my favorite pop artists Dua Lipa has this incredible show at Tiny Desk. Tiny Desk is an acoustic, live music show on YouTube. You can find big names mixed with a lot of indie artists from different genres. Dua Lipa might have one of the best ones.
Her sexy, pleasant voice is supported by a choir, a guitar, and a bass guitar. Add some simple samples and you’ll be blown away. My favorite song from the show is Pretty Please. Just layers of voices, after around 40 seconds the choir starts to take a greater part and with the mix of Andromeda ES and Questyle M15, you can listen to each voice individually. It made me happy to be able to enjoy one of my favorite shows to this degree. Are you craving something more fancy? How about an indie artist named Kevin Morby? On his album Sundowner, you can find this song called Brother, Sister.
Wait till the first chorus, where he uses vocalization followed by an acoustic guitar. The amount of insight into the sound that you are getting is really good. It is crazy how such a simple composition can speak to your emotions. Courtesy of the Questyle M15.
When it comes to treble, the M15 pushes them a bit harder, which is compensated by the Andromeda ES softness at the top. For this part, I relied more on the UM MEST. The treble of the Questyle M15 is big, and controlled.
The intro to the Sanitarium by Metallica features guitars supported by cymbals. Especially the first one sounds with a suitable impact. Emphasis on treble helps here to add extra energy and freshness to a pretty complex composition by one of my favorite bands. I do feel like the treble on the reviewed Questyle M15 tends to be a bit metallic, even when it comes to sounds that shouldn’t sound like that. Clandestina (Cocaine remix) by Filv, Edmofo, and Emma Peters is the song you know, but couldn’t remember what it’s called.
No thanks are necessary. Here the M15 presented a controlled and clear-cut sound, that sometimes felt a bit too hard. It is still a really good performance, but later on, you’ll learn about competition that does it better.
One of the biggest tests for sound staging was Dua Lipa’s show at Tiny Desk. I’m surprised by how well are those shows recorded. Reviewed Questyle M15 allowed me to easily place all of the musicians and singers in front of me.
Each of them was a separate sound source with no mixing between them. They were very close to me, as both Questyle M15 and Andromeda ES tend to have a closed-in presentation. For sound staging reasons I preferred the MEST with its tendency to explode the sound and push sources away from the listener.
The Questyle M15 does a good job at soundstage width and depth, but the competition is one step ahead. Really good performance on the part of M15.
Cayin RU6, NOS – $249
The RU6 by Cayin is one of the first dongles (if not the first one) to feature an R2R DAC. It promises and delivers a completely different sound signature than Delta Sigma DACs. It pushes the midrange into the first line. The treble and bass are pushed to the side a fair bit. The soundstage is much more open than on the Questyle M15. Refer to the Dua Lipa Pretty Please as a reference track. Pretty please.
Same thing on Clandestina (Cocaine remix), everything is much more open with more air between the instruments. In terms of bass, it is the weakest in the amount and the quality. Whether it’s Kanye West Black skinhead’s intro that lacks the bang, or Muse’s Starlight, with its famous bassline lacking the detail. It’s the bottom of the comparison here. Midrange, on the other hand, takes the cake, and with the Andromeda ES… It’s a crazy experience. I could have RU6 only to listen to the midrange. Kevin Morby’s Brother, Sister is magical. Natural, bold, thrilling voice and guitar. Absolutely top-tier performance. Neither M15 nor W4 have anything to say here.
With Dua Lipa’s show? Don’t even ask. I’m in love with her, just didn’t inform her yet. Please, call me. Pretty please? The treble on the RU6 is not as pronounced as in other dongles but is very light, sweet, and open. Less aggressive in Sanitarium by Metallica, either in the beginning or close to the end, it holds its own and compensates the amount with quality. Oh btw, don’t use UM MEST with the RU6. It doesn’t sound good. Anti synergy, just like me and pineapple pizza.
L&P W4, TUNE 1, Filter SLOW – $450
The W4 is still pretty fresh, as it had a premiere this year. The top dog from Luxury & Precision uses the LP5108, which is a combo of two DACs from Cirrus with some power regulators in a single module. I think they might oversold it a bit, as people feel deceived by the nature of the module. Still, there are some merits to doing that, namely great power delivery and decoupling.
You might have noticed the price tag. Yes, it’s not a typo. It is crazy expensive for a dongle (besides the ridiculous Gold Bar from iFi Audio). Yet still I can’t deny, that the W4 seems to be the best dongle on the market. In the top 3, no doubt. It takes the pros from both the M15 and RU6 but leaves out the cons. Pretty balanced character (with a small bump in bass), lots of power, and a great sound. It’s gonna be hard to return it to the owner. Thank you Grzesiu for lending it to me. Sound staging of the W4 is precise as with the M15, yet open and spacious as with the RU6. Take Dua Lipa’s Tiny Desk concert and it will be a top-tier performance.
The bass is not as powerful and dynamic as with the M15, but it still is excellent. Power, control, and detail. Doesn’t break a sweat with Kanye, and neither does fine detail with Muse. The midrange is not as good as with the W4, but it is pretty close. Detail, natural timbre, and smoothness can be heard throughout the whole Brother, Sister by Kevin Morby. Treble is another win, being the best out of all tested devices.
Open, airy, and sweet, but with enough authority to balance other ranges. The W4 played well with both the Andromeda ES and the MEST. It is a complete package, but it costs basically the same as the other two dongles combined. So, you know…
I will compare the pairing with the help of Tom Cruise and his two best roles.
Andromeda Emerald Sea
Andromeda ES with the Questyle M15 is like Tom Cruise in Collateral. Vincent was precise and calculated, yet charming and incredibly dangerous. The darker tuning of the Andromeda means you might want to use the silicone tips to get a more balanced response. The amount of precision this combo gives is incredible. As mentioned in our Andromeda ES review on YouTube, the Questyle M15 became my daily driver.
The bass from this combo will break your stereotypes about BA IEMs. It’s crazy good. The dryer midrange of the ESS Sabre family is greatly supplemented by the IEM’s richness in this regard. It still has plenty of charm. The top end gets dominated by Andromeda ES’ roll-off, so as mentioned before, you either deal with it or use silicone tips. I can live with that, as it is still a very respectable performance. All in all, incredible combo, and I can see myself using it for a long, long time.
The MEST with the M15 is like the best role of Tom Cruise. As a wise man named Les Grossman from the movie Tropic Thunder once said:
Now I want you to take a step back… AND LITERALLY F**K YOUR OWN FACE!
You can’t censor me, it’s a movie quote. This combo is just an obnoxious level of fun. It’s like the titular character, completely over the top. They will take you on a ride with a bass bigger than his bald spot. It will make you break some dance moves like Ludacris’ You don’t know me like that is in the air. But, on a more serious note. It’s a great combo.
The set with Andro is for enjoying music. This one is for enjoying yourself. Huge soundstage, with sound sources all around you, like assistants circling around Les. The Bass is something the MEST is known for with its bone conduction driver and the Questyle M15 takes full advantage of that. Just an ungodly rumble. The SiP amplifier is a very capable one. The midrange is on the back foot here as both devices don’t make it a priority. It’s still solid for the price, but let’s be honest.
You don’t buy the MEST for midrange, don’t you? The treble does an amazing job of countering the bass and making sure it doesn’t steal the show. Bright, bold, open and smug. Cuts through the low-frequency fatness like a pickle cuts the fatness of a pork belly on a sandwich. So to summarize it all, it’s an illegal amount of fun. If you like to always have fun, when listening to music, it might be a combo for you.
Questyle M15 Review – Summary
Good to see, that Questyle didn’t lose its direction over the years. Their focus is to make high-quality audio equipment and this review confirms that in my eyes. I have no doubt, that Questyle M15 is one of the best dongles on the market. Premium build quality and a fantastic sound are a testimony of that. While not as feature-packed as its competition, it steals the show with detailed, v-shaped explosive sound and great drive capabilities.
If you like the stereotypical sound of ESS Sabre DACs, you’ll be in heaven. Or maybe you are interested in a stupidly good-sounding dongle, that won’t drain your battery in 3 hours?
It’s not flawless though. The RF interference it can pick up when music is not playing is something that should be addressed. It happens very rarely, but still: shouldn’t. The other feature I dislike is the lack of integrated volume control. I would prefer not to use my smartphone for that since it was a challenge to figure out how to adjust the volume control step.
All in all, M15 still deserves a recommendation. I’m happy to use it as my daily driver, as it replaced my iFi Audio GO Bar. If you are on the lookout for a dongle that will drive anything while sounding mighty, you need to try the Questyle M15.
Big thanks to Questyle for providing the M15 for this review. I wasn’t paid or asked to say anything good or bad about this product, all of the above is just my personal, unbiased opinion.
I can really say “been there, done that” in regard to audio. Designing, building, fixing, reviewing, selling. All of that for big boy stereo. Headphones are something new and fresh for me. We all need something exciting now and then, so join me in my quest of discovering this cool world. We will listen to, drink and WE WILL bring the balance to the force. Oh, I like beer.