FiiO M17

The M17 is the flagship DAP from FiiO. But the M17 is not just any DAP, it is a true power monster! Legendary 2x 3W@32Ohm of the currently strongest DAP on the market drive any headphones, no matter how hard they are to drive. Whether this is really so I will try at the end of the review with my Susvara and Abyss 1266 TC.


It is delivered in two packages, one for the DAP including accessories and one for the docking station. The M17 comes pre-assembled with a screen protector. A replacement screen protector is included. Also a power supply for using the „Extended Over Ear mode“ and a USB-C cable. To protect the player, you can use the brown leather case, which is a perfect fit and has a clasp to prevent the DAP from sliding out. The back is equipped with metal air inlets through which the fan can do its work effortlessly in docking mode. The notches of the control buttons on the leather case are about 1mm apart, so you have to press with enough pressure to activate the desired function. With the included rubber pads, this distance is shortened and you have to exert much less pressure.

After opening, the brute size of the DAP initially blew me away a bit. I already know this from the iBasso DX320 Max Ti, but the M17 is still a bit longer and about as wide and thick as the iBasso. In terms of weight, both take nothing, about 600 grams. The workmanship of the CNC-milled aluminum housing is as the price tag suggests absolute top class. I also like the feel very much. Especially the large very handy volume control. Very good that FiiO has thought of a "Hold" switch that locks the buttons. Because if I put such a large DAP in my pocket, then inevitably sometimes accidentally pressed buttons. I would have liked to have this switch for my DX320 MAX Ti. The exterior lighting in the form of arrows in different colors also pleases me visually very well. Depending on the state (on, charging), these are permanently on or flashing. The color signals the bit rate of the played track. In terms of connections, everything is really on board here. Headphones and IEMs can be connected via 3.5mm, 2.5mm, 4.4mm and even 6.35mm. Dust protection sleeves are available for less needed connections like the 6.35mm output. The unbalanced 3.5mm connector as well as the 4.4mm balanced connector can function as headphone output as well as lineout. And of course, a "real" lineout is installed here, which does not pass through the amplifier section, but outputs the completely pure sound of the DAC. In addition to USB-C for charging/PC connection and a digital coax output, the M17 also has a 12V input for power supply operation where you can use the “Extended Over Ear mode“ and then up to 2x 3W@32Ohm with 27.7 Vp-P peak output voltage instead of 19.7 Vp-P are available. Since this also produces a lot of waste heat, the M17 can be operated on the docking station, which has an integrated fan that can be switched on with 2 speeds.



On the technical side, two ESS9038 DACs for digital-to-analog conversion and two THX AAA-788+ amplifiers work together to deliver the concentrated power in watts to the outputs. Of course, this requires a large battery, so FiiO gives the M17 a brute 9200mAh battery. Using USB-C and the QC 3.0/4.0 + PD 2.0/3.0 fast charging protocols, the battery charges in about 4.5 hours and then runs for an average of 9 hours. It can also be charged via the included 12V power adapter. The 5.99-inch display delivers a very bright and fantastic image.

In terms of software, FiiO uses Android 10. The whole thing can be operated very smoothly via a Snapdragon 660 with 4 GB of RAM. Internally, 64 GB of RAM are available, which can be expanded via a micro SD card. I would have liked a bit more internal storage here. FiiO's music player is very sophisticated and offers all necessary functionalities including EQ. Even a PEQ can be used, although it can only be added experimentally for now, since it is still in development. Other Android apps like the Neutron Player can of course also be installed and used.

A total of 5 gain levels are available. You can effortlessly fine tune very easy to drive IEMs (low gain) up to a Susvara in the last mode (Extended Over Ear Mode) via 12V power supply.

I tested the M17 with my two IEMs U4s as well as Foure Blanc from 64 Audio. In addition a Focal Utopia 2022 and of course the two hard to drive bolides, the Hifiman Susvara and Abyss 1266 TC. I tested the Lineout on my Niimbus US4 and compared it with the Topping D90SE, which, as you know, uses the same DAC from ESS.



The M17 sounds simply fantastic. It is totally balanced and here everything fits from bass to treble. This is another device where you don't have to crystallize individual components in the sound, but the whole thing is so coherent that you don't have to worry during playback whether the bass is very pronounced and detailed and the resolution is only average. No, every link in the chain fits together perfectly.

The power with which my IEMs and headphones are driven, you can just hear. Total control down to the lowest registers and really loud, if you like it, without losing control. The first time I used the M17 with the Utopia 2022, the planned minutes turned into 2 hours of listening.

Tonally, we have to do here with a neutral tuning that covers up absolutely nothing in the mids and treble and makes real steam in the lower range. Here, the M17 plays together with the DX320 MAX Ti in a league of its own. One, M17 with more focus on the low bass, the other MAX with more focus on detail from sub to midbass. Switching back and forth I can't decide who the winner is. It's different as so often, but not better or worse. The Impact in bass with the Utopia 2022 and Fourte Blanc is really amazing with rock and metal.



The ESS DACs are always said to have a very bright presentation. That is not the case here at all. The M17 sounds very clean and illuminates the treble range very widely, but at no time sounds harsh or obtrusive. To test this, I like to use my U4s, which can sometimes sound a bit sibilant with sources that are too bright. But this is not the case here. Absolutely brilliant treble reproduction and resolution.

Since the M17 plays sonically in places far above many other DAPs I compared it only with the DX320 MAX Ti. Both play as I have described very neutral and balanced. The differences are due to the DAC used and you can hear that most in the midrange. Neither discolors, each plays for itself an interpretation that leaves nothing to be desired. The MAX with a bit more fullness in the mids, the M17 a bit more stripped down and detached. The instrument separation succeeds both fulminant with the larger stage representation on the part of the MAX.

Excited I connected the lineout of the M17 with my Niimbus and then compared against the Topping D90SE and here both are tonally very close. The development of DAPs is currently so far advanced that these are now absolutely recommendable as source for stationary amps. Provided that they also have a "real" lineout like the M17 or MAX.

Even more exciting was my test in docking mode with connected power supply and “Extended Over Ear Mode“. Incredibly, I can enjoy my Hifiman Susvara and Abyss 1266 TC from now on on the terrace where a power outlet is available in a quality that seemed almost impossible before. No DAP that I know of can drive these two headphones as well as the M17. The distance to my stationary amp, the Niimbus US4 is of course still there in direct comparison, but nowhere near as great as before.

In conclusion, I can say that the M17 is a true powerhouse at the highest technical level. For those who not only own IEMs and easily driven headphones and would like to drive everything with only one device, which you can operate portable and stationary (for full power), I can recommend the M17.

EDIT: Bumped up my rating from 3.5 to 4 because of a software update to make the M17 a proper Roon endpoint. You can now listen to Roon with the full guts of the device. There is a NOTICEABLE sound improvement. Good riddance to the Fiio player. Overall, the device is still unjustifiably big unless you are going to be using it specifically for full-sized headphones and the sound quality isn’t quite on par with summit-fi players, but this software update means I can stop checking eBay for an SP3000 for a bit longer. AirPlay is still unusable.

Gear tested with the Fiio M17: 64 Audio Tia Fourte with balanced, palladium-plated Plussound X8 cable, Audeze LCD-5 with single-ended, silver-plated Plussound X8 cable, and Dan Clark Audio Ether 2 with single-ended DCA VIVO cable. What steered me toward the Fiio M17 was its ability to use Apple AirPlay. If that was also something that caught your attention, understand this: The lag between an Apple TV and the Fiio M17 over Apple AirPlay is unusable. It’s about a 3 second lag/delay, considerably worse than just using Bluetooth. So what’s left? A decent DAP that tries to do everything and continually stumbles.

Coming from an Astell & Kern SP1000M, I deeply appreciate access to the Google Play Store and Resilio Sync (By far the best file-syncing option). Roon works great, although I would say that the strength of the Wi-Fi reception of the M17 is “medium”. Roon also has to go through Android, so it is not lossless. The sound is good, not great. Despite the marketing department coming up with the term “Desktop class”, it is embarrassing to compare this to a good desktop setup. It has the power for full headphones, but it lacks good, dynamic sound. It feels flatter, less slam, and lethargic compared to the A&K SP1000M. I honestly considered the SP1000M and the Tia Fourtes to be one of the best sounding combos of any audio gear I have owned. When I plug the Tia Fourtes into the Fiio M17, I would say that the sound is better than the 2nd gen AirPods Pro, but barely.

It also has some bizarre quirks. The “Enhanced” headphone mode can ONLY be activated with the dumb charging brick. The brick is DC power! You have USB fast charging ports! You cannot activate the enhanced mode with USB power. WHAT IS WRONG WITH YOUR ENGINEERS? The Pure Audio mode UI is generally very good, but of course it has some obnoxious ticks to it. Searching for music is clunky. Manually updating your library seems wildly outdated. When browsing music, UI play buttons will either play music in series or play it randomized, and there is no indication what you’re going to get when you press the button.

I think this is a mediocre player that is offensively large. Like… you cannot comprehend its size until it is in your hands. Yes, it does have a full, real 1/4” port, which is insane. But even with earphones and the lowest gain setting and Wi-Fi turned off, the battery life is relatively decent. I haven’t thoroughly tested it, but I still have to charge it pretty often.

Overall, I think you have to have some extremely specific needs to justify the Fiio M17. I think that the vast majority of people can get similar sound for less, or spend a little bit more for better. Personally, I am definitely trying the Sony NW-WM1ZM2 and the A&K SP3000 when I get a chance.

The M17 was kindly provided by FiiO, free of charge in exchange for my honest evaluation.
The retail price is €1499.99 without VAT and you can buy it from FiiO.eu.

Introduction

FiiO has long ago decided to abandon the budget / mid-priced DAP category in order to concentrate their efforts on higher-end products.
They started with the M11 Plus LTD, featuring two AK4497 DAC chips, which after the chip shortage was succeeded by the M11 Plus ESS version and now they have released their cost - no object flagship, the prestigious M17.

FiiO M17

The M17 is the most complete and feature-rich DAP in the market, although it should be better addressed as "DAT" (Transportable player) rather than simple "DAP" since it is more of a transportable unit than really portable...
Full specifications are available here.

DAC and amplifier sections

The M17 uses a pair of the flagship ES9038PRO DAC chips from ESS in a fully balanced and differential configuration.
Each audio channel has 8 parallel outputs, summed together for superior resolution and minimal distortion.
The digital signal is handled through an XMOS XUF208 receiver and dual Femtosecond crystal oscillators which support up to DSD512, 32bit/768kHz PCM and 8X MQA.



For amplification duties, FiiO and THX have jointly developed the exclusive THX AAA 788+ module which is based on one OPA926F and one TPA6120A2 current feedback amplifier for each module.
Two such modules are used for a fully balanced output with a power output that can reach desktop levels up to 3000mW per channel.



Optimized circuitry

Top quality components are used like the high-end TI OPA2211 op-amp, 470mF DMF supercapacitor and ultra-low noise LT3045 LDO linear regulators while analog and digital boards are physically separated to reduce interference.
In order to accommodate all the necessary components and circuit boards while keeping the chassis as less bulky as possible, FiiO spent 1.5 years completing the highly optimized, modular internal structure.

Dual power supplies

This M17 contains two power supplies, a battery power supply and another one powered by an external DC power adapter.
The massive 9200mAh battery can be charged through a dedicated type C USB port or an external DC adapter.
The DC power supply mode offers 35% increased voltage to the analog circuit, up to +11.5V while the battery is kept healthy since it is not used under this mode.
The battery supports fast charging and it needs about 4.5 hours to reach full level while it can be charged either through the USB or the DC input.
With such high specs, someone would expect the battery to discharge really fast but in real life use it offered about 7-8 hours of playback from the balanced output but please keep in mind that this duration is largely dependent on the use scenario.
A very useful option is the battery life saving mode where the user can adjust the maximum percentage of the full charge.
Setting it between 70-80% is very good for the longevity of the battery.



DC/BAT switch explained

There is a switch on the right side of the player which allows you to switch between battery mode and DC mode, while you have the DC power adapter plugged in.
Without the DC power adapter the player is running from the internal battery and the user can't use the over the ear enhanced mode.
Plugging the DC power adapter will unlock the enhanced over-ear mode.
Then you can set the switch to DC or BAT position which have a different effect regarding power management.

In the hybrid power supply mode (BAT), the enhanced mode is not available but battery capacity can be kept full at all times, which is suitable for use in short-term fixed scenarios.
In DC power supply mode, which unlocks the enhanced mode, the battery life can be greatly extended because the battery is not involved in the working process at all.
For short-term usage, hybrid power supply mode is suitable. For better battery life, DC power supply mode is recommended.
In fact, as long as the M17 connects to DC power supply, all power supply is provided from the DC first.
In BAT mode, all DC power supply enters the PMU and then comes out to power other systems.
In DC mode, the DC power supply is divided into 2 channels, 1 channel enters the PMU and powers other systems, and 1 channel is directly powered to THX, which can provide a larger discharge voltage output and a larger swing.
So only the THX part uses DC power supply directly, and the other digital parts, as well as the analog parts of the LPF, are powered by the PMU.

Desktop level gain

Running from the battery there are four gain levels: low, medium, high and headphone mode.
When in DC mode, the enhanced over-ear mode is unlocked, with a truly desktop level amplification.
In balanced output, gain can get as high as 16dB, allowing the M17 to easily drive most of the headphones.



Bluetooth RX/TX

Bluetooth 5.0 connectivity is supported through the flagship QCC5124 chip.
The supported codecs are for Bluetooth reception: SBC, AAC, aptX, aptX LL, aptX HD, aptX Adaptive, LDAC and for Bluetooth transmission: SBC, AAC, aptX, aptX HD, LDAC.

Other notable features

The FiiO M17 houses a large 5.99" full HD 1080P display that produces crisp, high-quality visuals with stunning colors and detail while it uses Qualcomm's latest Snapdragon 660 SoC chip.
This is an eight-core high-performance CPU chip that delivers lightning-fast performance with applications. It also has 4GB of ram that allows for using multiple applications at once.
The FiiO M17 is loaded with the latest Android 10 OS that provides one with the widest range of media and music applications available with Google Play Store.

Heat management

Exceptional audio quality comes with large power consumption, so effective heat dissipation was a large focus when designing the M17.
Not only are "H" type heat dissipation and VC liquid cooling technologies adopted, the M17's 151g unibody aluminum alloy frame also effectively transfers heat out of the device.
Finally, the cooling fan stand also further makes sure heat is
rapidly transported away.

With all my headphones, that are not extremely difficult to drive, I haven't experienced any excessive heat above normal and never used the stand with the cooling fan.
The M17 was only mildly warm, even after a couple of hours of use.

The ambient light system

The M17 features a seven-color RGB ambient light system with
extensive customization options. Colors can be set to be either
fixed, to follow the audio, or to follow a cycle.
The brightness of the ambient light can be set to change depending on the current power, volume, or temperature.
And finally, the top
and side ambient lights can even be controlled separately, allowing you to dial in exactly how you want your dazzling lights to be.



Inputs/Outputs and Connectivity

The M17 features desktop level connectivity as it includes a great variety of inputs and outputs to cater for many different convenient use cases as you can see in the following diagram.
The 3.5mm and 4.4mm headphone outputs can be individually configured as line outputs with fixed or variable signals.
The USB type C and coaxial inputs are bidirectional and can be used either as digital inputs or outputs.

A few examples of connectivity are:
As a digital transport with an external DAC (USB/coaxial output+DAC)
Reading files from a hard drive storage (DC+USB 2.0+hard drive+headphones)
With Bluetooth headphones
(Bluetooth transmitter+Bluetooth headphones)
As a fixed line output DAC or preamplifier
Play music as a PC DAC or from an external CD transport.
(USB DAC input or coaxial input)



Accessories

The M17 comes bundled with a practical stand that has a cooling fan attached to it which by the way is not very silent.
There is also a premium leather case, an external DC adapter, USB 3.0 data and power cable, micro SD card ejector pin and aluminium dust plugs.
The screen comes with a gorilla glass protector pre-installed from the factory while there is an extra one included in the box.



Build quality and physical appearance/interface

The M17 is made from CNC milled aluminium with an excellent, flagship level, build quality.
The luxury, albeit very modern appearance, and the top craftsmanship certainly match the high price tag.
I am not very fond of the side ambient lights that are reminiscent of gaming PC gear and I would be happier without them but feel free to treat this comment as something purely subjective.
The finish is perfect while the volume knob and the side buttons are very well constructed and offer tactile feedback.

The unit is bulky and heavy, the dimensions are 156.5x88.5x28mm while the weight is a whole 610g.
This is not the regular DAP that can be used one handed, you are going to need both of your hands in order not to accidentally drop it.
As such the M17 is by no means portable and should be considered as a transportable unit, more suitable for stationary use.
The physical buttons layout is illustrated in the following picture.



User experience and interface

There are so many possibilities for using the M17 that it would be too lengthy to cover everything so I am going to refer only to the basics plus a couple of serious omissions.

The user can choose between the Android 10 OS or the pure music mode that enters the FiiO Music app, killing all other running applications, which offers marginally better sound quality.
For streaming services or DLNA the Android OS is the only viable option.
Other working modes include USB DAC, Bluetooth receiving, SPDIF RX, AirPlay and In Vehicle, while all of them are easily accessible from the drop down menu.
WiFi reception is strong and reliable, I haven't experienced any kind of issues while streaming high resolution 192/24 material.

The M17 is the first player to run Android 10, the overall use experience is great, the M17 is fast and responsive like a flagship phone, you can listen to music and multitask without slowing down the performance.
The M17 supports official Google Play so the user can install all his favorite applications without reverting to third party marketplaces.
The big screen has vibrant colors with excellent visibility, it supports double tap to wake, navigation and browsing is a delight to do, it can also be rotated and you can customize the touch control to use the gesture system or the classic 3-button layout.
I have opted for the latter since the external case was blocking my fingers and the gesture controls were largely missed.

The multifunction button on the left side of the player is very handy as the user can configure it with one of the available functions, like to change the low pass filter or add a track to the favorites.
Some functions are available only under pure music mode with the FiiO Music application.

For adjusting the volume you can use either the potentiometer or the side buttons.
The low profile potentiometer has a smooth feedback and is my preferred method of adjusting the volume but the truth is that the buttons offer a better, step by step, control.
With the potentiometer you have to carefully adjust because it is easy to get loud without noticing.
M17 is very powerful and the option to set a volume limit is a useful one.

Your music library can be loaded to a micro SD card but you can also use flash drives and powered external Hard Drives with seamless integration of all the music libraries.



Missing functions

Strangely for a flagship player, an ambient light sensor is missing.
Then the top shelf information bar will not display the current gain setting nor the digital filter that is selected.
Something very simple to do with two letters like "Gx" and "Dy" where the"x" will indicate the gain and "y" the number of the filter.
Another thing of note is that the filter selection is not directly available from the drop down menu.
The user must first enter the general settings menu, then select audio settings and only then is allowed to choose the desired filter.
Of course, you can always set the multifunction button to cycle through the available filters but then again you have no clue of which one is selected.
These two issues are great omissions and they should be addressed in a future firmware update, as soon as possible.
FiiO engineers are aware of the issues and they have promised to address them in a future firmware update.

Digital Transport / Receiver

You can either stream or have all your music library loaded to the M17 and use it as a high end digital transport connected to an external DAC through the USB port or the full sized coaxial plug.
Another handy and rare feature is that except the USB DAC mode there is also the unique feature for a DAP to set the coaxial input to act as a receiver so you can connect an external digital source like a CD transport.
I have successfully tested both functions of the M17 and remained completely satisfied.



Associated gear

The M17 was burned for 200 hours without bothering to monitor the progress regarding a possible change in sound quality.
Since this is a flagship DAP, I skipped all mid - tier headphones and I used only the "crème de la crème" like the Meze Elite, Focal Clear Mg, Sennheiser HD8XX, HiFiMan Arya Stealth and the HEDDphone.
My high-end earphone collection is rather limited so I was limited to the Meze Rai Penta, FiiO FH9/FD7 and Sennheiser IE600.



Listening impressions

Hugely dynamic, reference tuned, crystal clear, class leading transparency, are the first words that come to mind when trying to describe the sound of the M17.
The overall presentation is largely neutral with the best technicalities ever heard from a DAP, something not very surprising considering the dual ES9038PRO and the THX AAA 788+ amplifier modules.
But at the same time it is probably the most smooth and musical implementation of a THX amp that I have ever listened to, something that may have to do with the use of the TPA6120A2 as the core component of the THX module.
This IC is very frequently used, I have encountered it dozens of times during my audio journey and it never sounded clinical, something that also holds true to the M17.
There is a nice balance between technicalities and musicality and although the M17 is slightly leaning towards the former, nonetheless it is by no means boring or uninvolving.
It is pretty amazing how FiiO has managed to smartly equilibrate the M17 between reference transparency, the absence of any imposed character and yet stay enjoyable and addicting.
And it is not only about the THX amplifier; FiiO engineers have also succeeded in successfully implementing the notoriously strident ES9038PRO in such a way as not to sound digital and artificial.
I have tested various devices featuring this particular chipset and the M17 is among the ones with the least digital glare.

The M17 is the kind of the player where you are mostly going to listen to the source material and the headphones and not the device itself.
It is not adding a character of its own but rather is making sure that the signal remains in its purest form and gets amplified with the highest possible quality and fidelity.
The M17 is not suitable for trimming the sound signature of your headphones, bright will sound bright and warm will sound warm, boring is boring and musical stays musical.
You can't use it to alter the character of your headphone, the timbre gets set by the headphone and not the player.
Thus said the M17 is ruthlessly revealing, it is going to expose both the best and the worst parts of the recording and your headphones so just make sure that you have your all your hate and love relationships sorted out.



At this point you may ask, is there anything that this player does instead of not doing?
The answer is absolutely yes, the M17 is about muscular amplification with end game technicalities, about giving the most thunderous dynamics and holographic soundstage ever heard, exploiting every last drop of your headphones performance, pushing them to their limits at least as far as a battery powered device can go.
The macro-dynamics on the M17 are demolishing, impactful, it is going to shred your headphones into pieces with the most convincing sonic contrast you have ever experienced from a DAP.
Rise and fall speed is lightning fast, the player can get from ffff to pppp and vice versa in a split of a second adding a great sense of reality into the sound.
Listening to large scale symphonic works is a pure joy, an earthshaking experience per se.



The overall presentation is full and weighty, especially in the bass area, this is not a lean sounding player but it should be noted that it is a touch dry and not as liquid as some other DAPs featuring discrete components or tube output stages like for example the iBasso DX300 or the Cayin N8ii.

Honestly, the bass on the M17 is really amazing, visceral and extended deeply into the lowest notes yet always tight and controlled.
Multi-layering and clarity are out of this world. This is the most technically accomplished bass performance you can think of, just add a headphone that is capable of sustaining such a prowess, select the appropriate music, hit the play button and don't say that you haven't been warned.



Mid range and treble seem to levitate into space, appear from the void, they sound very open with crystalline clarity, excellent definition and the most fine articulation you can imagine.
Notes are born and decay in a natural manner, maybe a bit more rushed than ideal, while transient attack is exemplary.
On the other hand, higher register instruments are not too lush sounding or weighty as some might expect.
Harmonics and overtones are well resolved but they don't have the same kind of saturation and intensity as in some other players like the iBasso DX300.
The sound is by no means bright or fatiguing, the presentation is still neutral without either smoothing out or sharpening the edges.
Treble is linear and balanced without roughness but sometimes the upper part of the region feels just slightly detached.
Anyway the sound is by no means lacking in cohesiveness and integration between the different registers.

The M17 is highly resolving and deeply detailed but not analytical, you are going to hear every last bit of information, even if you don't want to, but thankfully in a polite and non aggressive manner.
Still, pairing with an analytical headphone might result in too much of a good thing, something that should be very welcomed by the detail junkies but not so desirable for the relaxed listener, so careful matching should be considered



Soundstaging abilities on the M17 are at a masterclass level, instrumental separation and placement into space are jaw dropping not only in the positioning accuracy but also in the way that the various groups are proportionally organized and focused.
Depth layering is phenomenal, as such the listener can pinpoint every last instrument in its exact location, while emerging from the deepest ranks of the symphony orchestra with great communication of the venue ambience.
The presentation is large, huge, full scale, grandiose and glorious but slightly lacking in the ultimate sense of holography.

Unleashing the beast

The M17 is already very powerful when running from the internal battery and was completely satisfying with all the headphones used.
Most of them are not very hard to drive and the over the ear gain setting proved more than sufficient with great driver control, spare headroom and ample dynamics, never needing more than 80-90 on the volume setting.
On the other hand, on the lower gain settings the M17 is dead silent with a pitch black background making it suitable for use with sensitive in-ear monitors.

Sufficient as it is running from the battery, the M17 might not be up to the task with more demanding headphones like the HEDDphone.
In such cases the usual procedure with other players is to resort to the line out with an external headphone amplifier.
Not this time though because the M17 has an ace up to the sleeve, namely the enhanced over the ear mode.
Plugging the external DC power adapter with the switch set to DC, will unleash the beast that dwells inside the M17, raising the performance to a level akin to an external headphone amplifier.
Larger voltage swing and higher current flow will not only cater for harder to drive headphones but it will also give you much better control, wider dynamic swings and increased headroom with your regular headphones.
The enhanced mode is really spectacular and while the M17 isn't going to substitute for a powerful external amplifier, it gets the job done better than you can probably imagine, adding greatly to the overall value of the player because most users will remain completely satisfied with the performance as it is without feeling the urge to purchase something else.



If there is a downside to the DC power adapter, that made me prefer using the battery whenever it was possible, is the slightest loss of the ultimate silence, background is not that black as with the battery.
This is something natural though because the THX amplifier is powered exclusively from the external power adapter which is not of the best quality and induces the slightest noise despite the internal filtering and regulation.
There is of course an easy, albeit quite expensive, fix;
Swap the power brick for a high quality linear power supply, like the iFi Elite, which vanishes the noise and raises performance to a whole new level, making the M17 a hard to beat all-in one solution.
Rumours are that FiiO is preparing a high quality linear power supply at a friendly price so stay tuned…



In the end

Digital player?, Streamer?, Transport?, Reference DAC?, Powerful headphone amplifier?, Preamp?, you name it all and the FiiO M17 has you covered at the highest possible quality while remaining transportable, quite compact, not too heavy and with an asking price under $2K.
A multi talented device that can successfully accomplish diverse duties from the obvious one of the Digital Audio Player to a fully featured desktop DAC/amp with top notch sound quality, whichever scenario you choose.
A milestone in the FiiO catalogue, witness to the great evolution of the company through the years, the M17 is probably the best transportable DAP on the market, an endgame audio device that successfully bridges the gap between portable and desktop audio gear.

Test playlist

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