FiiO K3 USB DAC and Headphone Amplifier Review

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FiiO K3 USB DAC and Headphone Amplifier Review

There’s no denying that FiiO makes the best sounding and cutest DAC/amps around for the price. And just when you think they’ve thrown down all their cards, FiiO releases another newcomer, the K3. What sets this DAC/amp combo from other famous FiiO models in this price range, like the Q1 Mark II? Let’s find out in this FiiO K3 USB DAC and Headphone Amplifier Review.

Review of FiiO K3 USB DAC and Headphone Amplifier

IN the BOX

FiiO K3 USB DAC and Headphone Amplifier Review


What separates the K3 from other FiiO models of this size is its added applications. The K3 can be used for the following:

  • Headphone DAC/amp combo
  • Straight DAC for external amp or active speakers
  • Digital connection between your computer and receiver

The other main difference is the power source. While most other portable FiiO DAC/Amp combos use an internal rechargeable battery, the K3 can only be powered from an external source, like your computer.

So let's get into the ins and outs....



The K3 connects to your computer with the included USB-C to USB cable. The computer will power the K3 through this connection as well.

FiiO K3 USB DAC and Headphone Amplifier Review

Headphone Outs

The K3 will accept a 3.5mm jack connection, as well as a 2.5mm balanced cable if you choose to take your fidelity to the next level.

FiiO K3 USB DAC and Headphone Amplifier Review

Analogue Line Out

If you’re using the K3 as a straight DAC, you can utilize the 3.5mm line out by connecting it to a pair of amplified speakers. Just make sure that when you use the line out, you unplug your headphones to avoid blowing them out.

Digital Outs

The K3 has also included an optical out (up to 96 kHz), as well as a coaxial out (RCA for 192kHz, support DSD64 DOP), which is handy if you need a digital connection from your computer to your receiver or amp (bypassing the internal DAC).

FiiO K3 USB DAC and Headphone Amplifier Review

Bass Boost and Gain

Even without the bass boost, you’re going to get a more forward sounding bass through the K3. But with the bass boost switched on, you can expect one boomy pair of buds. And if you have to push the amp to its limits and drive a higher impedance headphone, you’ve got a gain switch to lift it to turbo.


Despite its small size, the K3 is designed for desktop use. There’s no internal battery. As such, you will only be able to power the K3 from an external source, namely, your computer. So, this isn’t a DAC designed for mobile devices like your phone.

FiiO K3 USB DAC and Headphone Amplifier Review


If you are using the K3 as a headphone amplifier, note that this little thing can only power headphones up to about 150 Ohms. And generally, I would recommend this cutesy putesy for IEMs or cans with very low impedance.

Hi-Res Capability

The K3 can decode up to 384kHz/32 bit PCM and native DSD256. A little disco light will indicate the sampling rate and let you

USB Audio

Switch between USB 1.0 and USB 2.0.


There were a few major differences I noticed when playing my tunes through the DAC versus a direct connection to my computer. I used my trusty Campfire Andromeda (2020 and 2nd edition) with a 3.5mm connection. When using the K3, there was more bass presence, while any sizzle in the high frequencies was dampened. Of course, depending on your IEM, the characteristics may vary. But in general, you’ll hear a smoother quality with more detail, reducing the relatively compressed feel you get without a dedicated DAC. And if you go with a balanced connection, you can expect an even cleaner profile.


If you’re looking for an headphone DAC/amp combo that can double as a digital connection between your computer and receiver, I can’t think of a more adorable or more economical option than the K3. That being said, the K3 has no internal battery. So, it’s useless for on-the-go listening. And if you’re just looking for a portable DAC for your mobile device that also has a line out, then the FiiO Q1 Mark II is great alternative.

 Get it online or from our downtown Manhattan store.

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