Review: Fiio K5 – Fiio’s Budget Dock

Some Specs

The K5 according to Fiio has a high power output driving full-size headphones with ease. The amplification chip used is the TPA6120A2 and it delivers the following specs:

Output Power 1: >1.7W(16Ω/THD+N<1%)

Output Power 2: >1.5W(32Ω/THD+N<1%)

Output Power 3: >150mW(300Ω/THD+N<1%)

SNR: ≥110dB (A-weight) [AUX IN]

FR: 20 Hz~20 kHz±0.2dB

Output Impedance: <1 Ω(32Ω THD+N<1%)

Crosstalk: >70 dB (1 kHz)

THD=N: <0.002% (1 kHz 32Ω)

Max Output Voltage: >20 Vp-p

The K5 also offer synchronized power on/off for maximum convenience although I have to say it out of experience doesn’t always seem to work with my X7. Important to know is the USB is a “pass-through” only, that there is no difference in using the “USB in” port or the dock on top and that the RCA line out bypasses the volume control.


First thing you’ll notice when turning on the K5 is that after the click (to turn it on) you won’t hear anything until you reach a 9 o’clock position on the analog volume dial. Power is not an issue for the K5 and even at low gain, with the HE-400i, I never had to go above 11 on the dial and 12 o’ clock is extremely loud to me already. With the HD650 I easily listen at 12 o’clock in low gain. That does also mean the working range is only between 9 and 11 with the Hifiman, and that’s not a lot. With my custom monitors I can only work between 9 and 10 on the dial, there’s not a lot of room at all. (The impressions below, unless mentioned otherwise, are with the X7 + K5)


Sound signature wise I don’t find the K5 to add anything specific to the sound. The K5 doesn’t make the sound warmer and it doesn’t add any extra bass to it. Looking at the K5 like that, it is pretty transparent and the spaciousness is the thing that struck me most when switching from the X7 to the K5. For its price the amp inside the Fiio K5 is pretty good and there really is no complaining about it but on the other hand you clearly hear this isn’t a high end amplifier either. Layering, depth, dynamics and timbre compared to the higher (and multiple times the price) amps is lacking. Again, that’s all very normal but the thing is that I find the layering and depth directly out of the X7 pretty good, and I’m missing that with the K5.

The K5 by all means is a superb device but the amp part in my eyes just isn’t good enough in order for it to really transform your Fiio DAP in to a top quality desktop setup. Yes the K5 sounds a lot better than the X7 with Amp Module One (AM1) when using harder to drive headphones like the HD650. With IEMs I prefer listening to the X7 directly and it gets even more complicated: since I received the AM2 (medium power), I prefer listening to my Senn directly out of the X7 where the layering and depth, to my ears, are better. The AM2 module has more than enough power to drive the 300Ohm headphone with ease and it does really well with IEMs too. No, AM2 maybe won’t play as loud as the K5 but to me the sound quality is better. I still advise using a good amp with your DAP to get the most out of your harder to drive full sized headphones though (or you can use the RCA out on the K5 to connect it to a better amplifier and just use the K5 as dock). Don’t get me wrong, the K5 still is a great unit as it lets you use your harder to drive headphones and it makes your portable setup an easy to use desktop setup with charging and DAC capability. When you have the AM2-module however, it sound wise becomes more difficult as I find it to perform better than the K5.

More on sound on Page 3 after the click HERE or below


More on sound on Page 3 after the click HERE or below


Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.


  • Reply February 16, 2016


    Very thorough review. Would the sound improve if this ran off of a battery instead of the DC mains converter?

    • Reply February 17, 2016


      thanks, yes. I do think it would make the K5 even more quiet but a battery charged dock doesn’t deem too logic

  • Reply February 17, 2016

    Hasina Ihaja Rajaonarison

    Hi, thanks for this review but I wonder when will you do a full review of the Fiio X7 ?

  • Reply February 21, 2016


    Thanks for the review, just want to point a small error, the 1st page mentions that DAC function is only available for X5ii and X7, it should also include X3ii and the E17K.

  • Reply March 8, 2016

    Rafael Nascimento

    Hi! Thanks for the review.
    Today I have the E07K, but I think I need more power before I buy an DT990 600, so I wonder if I should go buy the old dock (E09K) or get some newer amp (K5?) to use together with the E07K?

    • Reply March 8, 2016


      I wouldn’t use any of that gear with a 600ohm version

      • Reply March 8, 2016

        Rafael Nascimento

        🙁 Then what would you recommend for these cans? (That’s not over $300)

        • Reply March 8, 2016


          a lower ohm Headphone. One shouldn’t get the 600 if there’s no room for a decent amp

  • Reply March 12, 2016


    I’m planning to buy this dock for a desktop system alongside my iMac and Fiio X3 2nd gen (used in DAC mode).
    I would use the system both for headphone listening and connected to a pair of amplified loudspeaker (still to be bought…).
    do you think that this solution is OK compared to a DAC/hp amp in the range of $200/300?

  • Reply September 9, 2016


    Thanks for this interesting review !
    I’m planning to buy a K5 for my FiiO X5 II. I just have a question, I want to use it only as a simple dock connected to my amp as I find it more esthetical and practical than a simple jack to RCA adapter : is the sound quality affected by the K5 ?

  • Reply December 26, 2016


    I have the X3ii and HE400i on order. I’m trying to decide between this K5 and the Schiit Magni 2. I like the K5 because it’s an all-in-one solution, and only like $80. Will it be enough or should I get the Schiit?

  • Reply December 26, 2016


    K5 is ok but I would suggest investing more in an amp for a headphone of that quality

    • Reply December 26, 2016


      Any particular suggestions? The Schiit Magni 2 is the only other thing I’ve found around that price that puts out enough power.

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