Review: Fiio X3 II (portable music player)


Mis à jour le 26 February 2019.

This week we’re testing the FiiO X3 MK2 digital audio player, whose technical features will really whet your appetite, just as much as the price considering all the device can do. MP3 audio playback, FLAC files up to 24 bits/192 kHz, DSD 64/128, external USB DAC mode, gain switch for ?tricky? headphones, aluminum cover. With such an endless list of features, we couldn’t wait to try out the FiiO X3 MK2.

Fiio X3 MK2

FiiO is a Chinese brand, specialising in the manufacturing of small portable electronic devices with an outstanding reputation. These include, headphone amps, DACs, portable DACs and digital audio players. The current range features the FiiO X1, FiiO X3 MK2 and the FiiO X5.

MK2 stands for Mark 2 as the FiiO X3 MK2 is the successor to the FiiO X3. This is a revamped version with many improvements such as a new converter, a longer-lasting battery, an aluminum case and a new visual identity (taken from the recent FiiO X1). The Wolfson WM8740 converter has been replaced by the Cirrus Logic CS4398 ? a chip frequently used by Marantz or Astell&Kern and capable of handling 16 bit/44.1 kHz (MP3, FLAC, ALAC, etc.) to 24 bit/192 kHz (FLAC, WAV) audio files as well as DSF (DSD format). It’s quite simple, the CS4398 chipset is the highest quality model developed by Cirrus Logic. The FiiO X3 MK2 has no internal memory and requires the purchase of a microSD card to copy audio files.

Fiio X3 MK2
The microSD card must be inserted with connectors facing upwards

Different uses

As the FiiO X3 MK2 is a portable device, its main use is playing audio files with headphones, without being ?connected’ to a hi-fi system or computer. You can therefore carry it around with you. The micro USB socket has many different uses. It can be used for charging the device from any powered USB port (power supply is not supplied). Its second use is for transferring files to and from the installed microSD memory card.

Fiio X3 MK2
The FiiO X3 MK2’s main menu
Le Fiio X3 MK2 peut être utilisé comme un DAC USB
The FiiO X3 MK2 can be used as an external USB DAC with any computer

It can also be used to read audio files from a USB flash drive in OTG mode (a microUSB cable to female USB A is then required. This is not supplied). Finally, it can be used as an external USB DAC with any computer. Note that with Windows, a driver must be downloaded from the FiiO website.

How convenient and responsive is the FiiO X3 MK2?

The FiiO X3 MK2 uses the same features as the first models of iPod ? a click wheel surrounding a select button, used to validate the selection. Additional buttons around the wheel allow users to change track, come back to the previous menu and display a list of options (shuffle, non-stop, adding/creating a playlist, deleting the file currently playing, etc.). Volume is controlled using two buttons on the left. Holding down the button when the screen is switched off takes users to the previous or next file. The power button allows users to reactivate the screen which automatically switches off (after 30 seconds or more if this setting is put in place).

Fiio X3 MK2
The power and volume buttons are installed on the left side of the device. The opening which can be seen is that of the reset button set to factory settings.
Fiio X3 MK2
The stereo line output can also be used as an S/PDIF output to connect the FiiO X3 MK2 to an external DAC or amp with DAC. A cable is supplied for this purpose.
Fiio X3 MK2
The microUSB connector allows the device to be charged or used as a DAC. It also enables files to be read from a USB flash drive or to be copied to the microSD card. It can be accessed even with the protective silicone cover in place.

Is it convenient? The simple answer is yes, given that significant progress in terms of user-friendly features has been made since the iPod. You can get quickly accustomed to the FiiO X3 MK2’s controls without any major difficulty. A touch-screen would, however, have been a lot more convenient. Browsing is relatively straightforward and the return button always brings you back to the file currently being played. This is a good point. What’s slightly more annoying however is the fact that you have to change the status of the FiiO X3 MK2 in the settings when connecting to a computer. We would have liked the device to offer us either the USB DAC mode or file transfer mode when connecting.

Is it fast? Yes, very fast, which is a nice surprise. Regardless of the selected file resolution, playback is immediate and switching from a FLAC to DSF file is instantaneous.

Is the device compatible with high impedance headphones?

The FiiO X3 MK2 DAP is fitted with very solid OP amps. Gain adjustment, using a Sennheiser HD-800, allows a very high sound level to be obtained, from 2/3 of the volume range (from 80 on a scale of 0 to 120). The presence of a 10 band equalizer allows the listening balance to be easily corrected.

Fiio X3 MK2
The Fiio X3 MK2 offers gain adjustment for high impedance headphones

Test conditions

We listened to the FiiO X3 MK2 DAP with two different models of Sennheiser headphones ? our faithful PX-100 and an HD-800 model. Our test’s memory card contained FLAC (16/44 to 24/192) and DSD files. We were surprised to discover that multi-channel FLAC files are handled, downmixed and played in stereo. This was also surprising as ISO SACD files are handled perfectly ? all track titles are displayed. Further good news is that the indexing of 250 files took less time than that required for taking a screenshot.

Fiio X3 MK2
Indexing of the 250 files present on our 32 Gb card. These are then categorised by title, album or artist

Listening impressions

Once the break-in period (where listening is a bit dry in both the medium and treble) is over, the FiiO X3 MK2 offers a solid listening experience, rich in character with slight emphasis in the medium range. There is a high rate of information transferred to the ear.

While it’s swarming with information, it remains well structured. The sound stage is very ?dense?, wide and particularly deep.

This FiiO X3 MK2, with its lively character,  reminds us of the Encore mDAC with infra-bass in addition. We listened to Chet Baker, Ahmad Jamal, Rihanna, Supertramp and Muse to name a few, and we were never disappointed. Battery autonomy exceeded 10 hrs during tests.

Fiio X3 MK2
The Fiio X3 MK2 comes with a soft silicone protective cover which still allows you to access the device’s various buttons


Despite its dated design, the FiiO X3 MK2 DAP fulfils all expectations. Very responsive and functional and capable of being used with large hi-fi headphones, this device can gently caress your ears as well as rattle your eardrums. The audio message is always articulated and lateralization is pleasing. This is a portable player with real character.



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