Review : FiiO K3 – Legacy


Inside the box

The FiiO K3 bundle is very dire :

  • 1x USB Type-C Cable
  • 4x Silicons Pads
  • 1x quick-start

And that’s it…

I know the FiiO K3 is supposed to be an affordable desktop USB DAC, but I would have like to see at least a set of cables to connect it. Otherwise, the silicon pads work well and once fitted, the FiiO K3 doesn’t move from the desk anymore.

UI & Usage


The FiiO K3 installation is very straight forward, you put the USB cable into the K3, the other side to the computer… et voila. If you have a modern Windows computer or OSX, the installation doesn’t take more than a minute. If you have an older computer you’ll have to download the latest FiiO USB driver from their website. Again, with a modern internet connection, this should take you no more than 15 minutes, installation included.

Of course, that’s only if you use the 2.0 USB Audio mode. The 1.0 USB Audio mode is completely driverless on any platform so if you’re in a hurry, that’s your way to go. Surely, if you’re that much in a hurry you should do something else with your life, audio is like wine : it takes time to fully enjoy it.

Once installed, the FiiO K3 supportss audio stream up to 32bit / 384kHz and DSD256 which is pretty rare even now. The K3 only needs 500mAh to power up, so you can just connect it to a hub and it will power up once you turn the knob.

DAP/Smartphone USB

The FiiO K3 can be plugged to almost any player, as longs as it supports USB Audio Out… allegedly. Most of the time, you’ll need a USB adapter, but in some case you can just use a USB Type-C to Type-C connector.

If nearly all devices accepted the FiiO K3 in USB 1.0 mode, USB 2.0 Mode was a bit more tricky. I achieved to make it work on my iPhone and iPad, but with the A&Ultima SP1000M that just didn’t work. Strangely enough, the A&Norma SR15 worked straight of the box, so this might just be a software issue.

On iPhone and iPad, the message “this device needs too much power” appeared whatever I did. Too bad as those should have been a great solution on the go ! You’ll have to rely on the FiiO Q1 Mark ii, still a good device but not as cool in my opinion.

Depending of the device, volume control was muted on the phone and could only be controlled from the FiiO K3. I think this is much more intuitive than having two different volumes to control each time…

Everyday use

There is not much to say about the FiiO K3 in term of ergonomics, there is no screen, no UI, no battery. The only options you have are the gain and the bass, plus the volume of course.

The volume knob is very well made, there is enough resistance to finely tune it, and not too much so you don’t flip the K3 each time you turn it up. The switches are so small that you’ll have to take the whole DAC each time you need to activate them but, other than that, nothing special.

The SPDIF output is a full-fledged Toslink port, and this is a good thing. This way you don’t have to buy a mini-toslink adapter and you can just plug your good old toslink cable right away. Sadly, FiiO isn’t providing any accessories with its K3, so you better buy them at the same time… The Coaxial output is a standard cinch port, you can just plug it to your DAC and it will work seamlessly too.

The line out is less powerful than usual, claiming a shy 1.9 Vrms instead of the classic 2.1 Vrms. Still, you won’t hear a massive difference as what really counts is the overall sound quality. If you want to use the FiiO K3 for a set of power-amplified speakers, you can just set the gain a bit higher than usual.

Interestingly, the volume can be adjusted if the line out is plugged in, but not if the optical out is used. So you better not forget to unplug to optical out before you plug your headphone, that could go *bam*.



In a world where everyone is using Sabre ESS chips for his desktop DAC, an irreducible brand keeps using AKM chips. After Wolfson, after Burr-Brown, the FiiO K3 is now embedded with an AKM AK4452 DAC.

Available in four versions, the AK4452/AK4454/AK4456/AK4458, this DAC was issued in the Velvet sound series and supports files format up to 768kHz/32bit. The only difference between each version is the number of channels they support, 2=2 channel, 4=4 channels, etc…

At 115dB of S/N ratio, it’s not one of the most impressive numbers we’ve seen out there, but that’s still plenty enough to appreciate it. Even if you only have 24bit files on your computer, or DSD. The AK4452 supports DSD too, yes, DSD64/128/256 and that is quite a surprise as most entry level DACs don’t go higher than DSD64.

This is all thanks to the XMOS XUF208, the chip acting brilliantly as a multi-platform bridge. It supports all major modes : WASAPI, ASIO, KS, DS and even DOP for DSD. I mainly used WASAPI mode with AIMP3 on my computer, this remained my main configuration for years now.

Usually you can choose which roll-off filter you will use, not this time. I checked inside FiiO USB driver parameters and couldn’t find it, so maybe this will be an option in a software update. A little quirk, the light-ring around the volume has three different colors, depending of the sample rate:

  • < 48kHz : blue
  • > 48kHz : yellow
  • DSD or 24/32 bit : green

Audio amplification

The Fiio K3 supports both single-ended and balanced output. Still, even in balanced mode, the output power isn’t very high with 200mW @ 32ohm. If you plan to use big cans or drive planar headphones, I think you’ll feel more comfortable with an additional headphone amplifier connected to the line-out.

The Low Pass filter is made of one OPA1612 from Texas instrument, an ultra-low noise/distortion with less than 0.000015% at 1kHz (!). To drive your headphone, the FiiO K3 gets a double TI OPA926, an OP AMP which is already at work in the FiiO Q5, a good omen. They are mounted in double mono configuration, so you should get the same wide sound stage you had with the E10K.

Again, the power output is relatively weak on the specs sheet, so I’m pretty curious to see how that will end in terms of sound. The drive ability is supposed to support 16-150 ohms impedance, so I’m gonna test it with difficult headphones.

Full specs

  • Type : Digital Audio Player
  • USB : XMOS XUF208
  • DAC : AK4452
  • LPF : Ti OPA1612
  • BUF : 2x Ti OPA926
  • Sample rate : PCM : 8Hz – 384kHz (8/16/24/32bits) native – DSD64/128/256
  • Outputs : 3.5mm headphone out / 2.5mm TRRS out / Coaxial Out / Optical Out / Line Out
  • Input : USB Type-C
  • Volume Knob : ADC
  • Drive Ability : 16-150 ohms
  • USB Audio Class : UAC1.0 + UAC2.0
  • Driverless in USB 1.0 / Driver needed in USB 2.0 (automatic installation with OSX and W10)
  • SNR : > 113dB
  • THD : < 0.004%
  • Frequency Response : 20Hz – 80kHz
  • Crosstalk : > 70dB (1kHz)
  • Line level : 1.9Vrms
  • DAC : 384kHz/32bit
  • Output Power 3.5mm : 220mW(16ohm) / 120mW(32ohm)
  • Output Power 2.5mm : 320m(16ohm) / 200mW(32ohm)
  • Max Output Voltage : 7.39 Vp-p
  • Max Output Current : 81.6 mA
  • Size : 70mm*58mm*22mm
  • Weight : 82g

The review continues on Page Three, after the click HERE or by using the jump below.

3.9/5 - (40 votes)

A nerdy guy with a passion for audio and gadgets, he likes to combine his DAC and his swiss knife. Even after more than 10 years of experience, Nanotechnos still collects all gear he gets, even his first MPMAN MP3 player. He likes spreadsheets, technical specs and all this amazing(ly boring) numbers. But most of all, he loves music: electro, classical, dubstep, Debussy : the daily playlist.


  • Reply December 20, 2018

    Loganaden Balakrishna VEERAPEN

    Big thanks Nanotechnos for this excellent review. Lately I’ve been on the fence to replace my trusty Fiio E10 (which I use with my android phone) with either the K3 or Q1 MkII (only power output and sound quality are my criteria). I know its Berkhan who reviewed the Q1 MkII, however I would very much appreciate if you give a brief comparison to the K3.

    • Reply December 31, 2018


      Personnaly, I’d go for the K3 if it’s for a desktop use. The Q1 is very nice, but I think the K3 outperforms it, especially with its better soundstage 😉

  • Reply December 20, 2018


    i’ve got an fiio a3 that i pair with my v-moda crossfades & i use them for absolutely everything; music, games, movies, etc.

    i realize both are somewhat outdated but the two work phenomenally together and i don’t see an immediately obvious reason to upgrade!

    best qualities are definitely sound stage and lower frequencies, which i’m big on a lot of bass and surround.

  • Reply December 20, 2018

    Sæmundur Eric

    Hi, how would you chose Q5 or K3 from Fiio ?

    • Reply December 31, 2018


      The Q5 is better overall, but it’s also more expensive and bulkier

      • Reply March 3, 2019

        Im a newbie

        Hello, nice review ma frend.
        But, im curious how the k3 compared to ifi nano bl?

  • Reply December 28, 2018


    does K3 wil be good pair for fiio fh1? im planning to get them both , does the K3 do the “Pooping” sound when plugging an iem to it? i have fiio e10k it does produce “poop”sound when i plugging my iem even in zero potensio ( idk what caused this and im afraid it will harm to my iem)

    • Reply December 31, 2018


      Fortunately I didn’t hear any pooping (like the word) with the K3. I think they used a better filter to avoid feedback like this. 🙂

  • Reply December 28, 2018


    I want to use a Headphone Dac/amplifier for my laptop just to improve the sound when listening to YouTube etc. What would be better the Fiio K3 or the Schitt Fulla2 if I was to use Beyerdynamics T990 headphones?

    • Reply December 31, 2018


      The Schiit should have more power to drive your Beyerdynamic.Also, it will sound a bit more metallic, the highs are a bit too proeminent for my ears. Both are solid performers, take the Schitt if the Beyer is you main headphone, the FiiO for everything else.

    • Reply April 24, 2019

      Maksym Nits

      With such a nice setup you’re planning to have, listening to music from YT is a sound quality killer. Download only in CD-quality, like .flac, .aac, an so on. Forget about mp3 and YouTube, respect your ears and the gear you own that companies tried to make perfect for so long!

  • Reply January 9, 2019



    I’m looking for a DAC/AMP for my pc to drive my new Hifiman HE4XX headphones. This will be my first DAC/AMP btw.

    Do you think this will be sufficient or should I shoot for something better?

    I’m guessing the K3 can be connected to an iphone but that would drain the battery, am I correct?

    Thank you, nice review!

  • Reply January 15, 2019

    Alex Di Lolli

    Great review, did you had the chance to compare it to the iFi nano iDSD BL?

  • Reply February 17, 2019


    Hi, nanotechnos, does K3 can drive hd800 without any problem at all? in SE and balance? Thanks

    • Reply February 17, 2019


      No it’s not build for that really

  • Reply April 6, 2019


    great review, thank you! I’m interested in using this device to improve the sound quality of my laptop setup. I have a macbook pro into which I’m plugging JBL LSR305 studio monitors. Would plugging the speakers into this unit and then the K3 into my macbook pro be an effective solution for improving audio quality? I’m primarily streaming Qobuz using the Audirvana app integration.

  • Reply February 24, 2020


    i want to buy and use it for hd58x jubilee , its good for this can ?
    i should decide between k3 , e10k and dragonfly black ? which one do you suggest ?

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