Today, Louis reviews the Questyle M18i, a new flagship ES9219Q and wireless-capable dongle DAC with balanced Current Mode amplification. It is currently priced at $349.
Disclaimer: This sample was sent to me in return for my honest opinion. Headfonics is an independent website that does not have any affiliate links. I thank Questyle for this opportunity.
Click here to read more on other Questyle products previously reviewed on Headfonics.
This article follows our current scoring guidelines, which you can read in more detail here.
When I received the newly released Questyle M18i, I was simultaneously perplexed and surprised. Because I assumed it was getting an upscaled dongle DAC over the M15 and the other models like the M15C and the M12.
However, the M18i has some new tech in addition to some updated audio hardware. This time around, the M18i also received modern-day Bluetooth receiving proficiency, which raises the bar when it comes to portability and usefulness.
That changes this device’s category and places it with the dongles, such as the iFi audio GO blu, or the FiiO BTR17, or bigger components such as the Shanling H2, given the price point.
Questyle’s main challenge here is to offer something over those mentioned models since the retail price sits at $399, placing it on a higher tier.
Questyle has reduced the price of the M18i to $349 at the time of writing, so this might be a good time to purchase one.
Features
Questyle worked alongside ESS to develop a TTA DAC framework and implemented this design using a pair of up-to-date ESS ES9219Q. These quad-tech, 32-bit chips have an analog volume stage, which I thought was one of these chips’ coolest features.
The M18i’s main audio circuitry uses a three-stage design that takes the output of the DAC section to a CMA or current mode amplifier preamplifier section that then feeds a quad current mode amplification stage.
Modern-day codecs and formats are absent from the M18i, like MQA, which to me looks as if they’re losing the battle against other formats, and Questyle seems to know that.
The M18i instead offers decoding rates of up to PCM 384k plus native DSD256 alongside a plethora of compatible Bluetooth formats at up to LDAC level.
The modern-day 16-core XMOS316 solution handles the M18’s USB input stage, and on the Bluetooth receiving end is a Snapdragon 5.4 BT solution.
Combined with the aforementioned hardware, makes up a formidable package within this segment and thus, takes the Questyle flagship position for obvious reasons.
Questyle is shy when it comes to amplifier specifications. I know that the M18i employs a patented Questyle Current mode technology amplification section that’s capable of around 28mw at 300Ω, but that’s most of the info given by Questyle.
I can see a four-chip setup in the circuitry diagram. The M18i uses Questyle’s CMA SiP tech, similar to what their CMA18 had. Perhaps that’s where the model number 18 idea came from.
Design
The M18i is assembled from a chunk of high-grade Aluminum shaped in a CNC machine. In previous models like the M15 and the M15C, the glass insert treated the user to a view of the intricate circuitry, but in the M18i, it forms part of the fully laminated OLED screen and is blacked out.
On one side, there’s nothing except for the red charging USB-C port, and all the buttons are on the opposite side of that. Five buttons cover all the M18i’s features. There are two volume controls with 60 steps of adjustment.
Then there’s the power button, which also doubles up as the screen wake button. There’s also a multifunction button labeled MFB, which combines a two-way gain with a phone call pick-up and hang-up button. In BT mode, the MFB becomes the pause and play button.
I could not find any submenus or tucked-away features like on most dongle DACs with a screen, and it solely serves as an information screen. The screen shows you the input selection status, bit rate, battery status, volume position, and gain status.
Aesthetics
There is a simple element about the M18i that I like. It doesn’t catch your eye like some other dongles that employ an artistic flair in the design. In this case, it’s just a black rectangle with some buttons and headphone ports.
The button layout seems to be oriented for two-handed operation between the two index fingers and the thumbs, but it can also be operated one-handed and thumb-operated. There is no screen rotation feature that I could find on this unit.
The dongle is not too big, but it does have some sharp corners. It’s a medium-sized dongle veering on large, but the weight is not too bad. I think Questyle should have thrown in a protective case. Lots of manufacturers do nowadays. At this level of tier, it should have come with one.
I/O
There are four ports on the M18i: two 3.5mm and 4.4mm headphone ports and two USB-C connections. Here is where it gets interesting, as the two USB-C ports serve different purposes.
There’s a red-colored USB-C port that is strictly used for charging the battery, but you can also use the data USB-C port for that, which is the black port. The red port charges the battery no matter what mode the M18i is in, but the black port can only charge the battery when it’s in desktop mode.
Another thing I noticed was that the two-position gain switch does not work when the unit is placed in Bluetooth mode. The gain feature works in PC mode and Mobile device mode.
If you need to set the gain and you want to use a particular gain setting in Bluetooth mode, you can always switch over to one of the other modes and adjust the gain in another mode, and return to the previous mode.
The setting will stick if you go back to Bluetooth mode from another mode, which alleviates this.
Battery life
I was surprised that the Questyle had an internal battery because again, I thought it was a simple dongle and most depend on the source’s power, but the runtime wasn’t stellar, and I obtained around 3 hours on IEMs and 2 hours with full-sized headphones.
The battery here is the main power source, and in that manner, the M18i avoids using noisy circuitry and isolates the noisy charging circuitry from marring the audio quality. But you can always use it in desktop mode and with an additional power source.
Charging initiates when you plug a charger into the red USB-C port, which works out well when you’re in desktop mode, but you can also charge the unit via the USB-C input port in desktop mode.
There seems to be an absence of quick charging on this model, and it took me at least a couple of hours to charge the battery up to 100%.
The internal rechargeable Lithium battery has a capacity of 500mAh, which is an acceptable size. But I’m still waiting for user-replaceable batteries from the industry.
Packaging & Accessories
There’s not much inside the box. The Questyle M18i is another dongle that, although compatible with gear that’s equipped with Lightning connectivity, none is included.
You do get a dual USB-C cable and a full-sized USB adapter so you can use the M18i with any full-sized USB-equipped gear. There’s also an owner’s manual and a warranty card.
Packaging is simple and effective. It’s a small rectangular box with slide-out drawers that contain the dongle and all the accessories within a custom foam mold, which is a secure way of shipping goods.
Sound Impressions
My test bed consisted of my Motorola Edge with Android 14 and a custom AMD PC that uses a voltage regulator to filter the power input. I used the HIFIMAN Arya Unveiled, the FiiO FX17, the Grand ORIVETI Supremacy, the Sennheiser HD 505, and the HD 490 PRO Plus.
Summary
The Questyle M18i is all about tonal balance, with a reference-like tuning that does not alter or emphasize any area of the frequency response range. Timbre is natural and life-like, and there’s no harshness or bloated tones.
You get a sense of cleanliness, with excellent clarity that gives a high-end sonic impression. It attempts to reproduce the source as faithfully as possible with as little coloration as possible.
Bass
The bass response is tight, controlled, and well-restrained. The bass is produced with a good body and decent depth. It’s to the point and unbloated. It’s clean and ‘ruler-flat’, catering to detail instead of forcefulness.
Again, there is a studio-like presentation because there’s no emphasis in any area of the bass response, leaving room for other frequency bands to flourish due to the lack of bleed into the mid bands. The bass is what I call proper and unbiased bass.
If whatever gear you’re using is up to producing clean bass notes, the M18i will complement that set by producing bass notes that are distinct and true to the source.
Midrange
The midrange is transparent and detailed and is effortlessly produced by the M18i. It’s produced with a natural timbre and an accurate tonality that grabs you since it remains pleasantly articulate.
There is a mild warmth in the midrange area and upper bass region, but I think it’s a common characteristic of ESS DACs. That character translates into vocals that are neutral and realistically portrayed.
Overall, the midrange characteristics of the M18i are non-belligerent and reference-like, but somehow it detours from sounding too sterile and presents mid frequencies with body and texture.
Treble
The treble is airy and with effortless extension. It’s a neutral treble that is very clean and free of coloration. It’s also free of excess sharpness that can be annoying to the listener in long listening sessions.
The background is dark, and that enhances the highs by allowing them to be reproduced with clarity, which makes the M18i a good candidate if you’re looking for gear that’s non-fatiguing but detail-oriented.
The high frequencies are produced with lots of resolve and a high amount of definition. One can consider them studio-like, which seems to be a common trait in the M18i’s tuning since it’s unbiased in any particular frequency, and since you can also say that for the rest of the frequency response.
Staging & Dynamics
One of the top characteristics and abilities of the M18i is the soundstage it can produce, and I have to commend Questyle for producing one of the best dongles in this category.
The 18i can produce a 3D-like panorama that includes lots of depth, height, and width. On top of that, it’s capable of producing lots of precision placement.
This is one area I have found other dongles lacking: soundstage size and precision. Not only does the M18i cover those aspects, but it does so without losing focus. The M18i keeps elements tidy and avoids smearing and conglomeration.
Click on page 2 below for my recommended pairings and selected comparisons.
