Fiio has unveiled K3, the pocket-sized headphone amplifier and USB-C DAC which upgrades your music to high-fidelity sound in a small package.

Key features

Boosting sound with capable decoding

Equipped with an XMOS USB receiver chip, the FiiO K3 is capable of decoding up to 384kHz/32 bit PCM and native DSD256. The K3’s dual crystal oscillators ensure that any digital audio signal being fed into the DAC is corrected for further enhanced sound quality.

Highly optimised architecture for maximum potential

The K3’s well-thought-out internal design consists of two main layers, working flawlessly together in harmony. Digital processing is carried out by the high-performance AKM AK4452 with 32-bit VELVET SOUND technology and fully differential outputs for true balanced output, while the analog signals are handled and amplified by a design consisting of LPF/voltage amplification and a current drive circuit.

Eliminate the noise with low-distortion op-amps 

The combination of the proven OPA926 with its low-distortion, low-noise, and high output swing along with the professional-grade TI OPA1612 acting as the low-pass filter (LPF) ensures the FiiO K3 effortlessly provides highly resolving sound, pumping out 320mW at 16Ω from the balanced output.

Reliable and stable connection

The K3 adopts the modern USB Type-C input interface for a more reliable and stable connection. It implements overvoltage protection (OVP) and a double-filter circuit to ensure power supply stability, while the digital and analog audio circuits each get their own power supply to greatly reduce crosstalk.

Eliminate channel imbalances with ADC volume control

An ADC volume control is implemented in the K3 to effectively eliminate channel volume. With the reconstruction of the ADC curve, it provides an accurate and finer degree to adjust the volume smoothly, allowing K3 to be paired with headphones of all kinds of sensitivity for a variety of listening needs.

Gain and bass switches to enhance your experience

The switch for high and low gain ensures that you can use the K3 with a wide variety of headphones under various ambient environments. The hardware bass boost switch enhances the dynamic range of the lower frequencies and delivers an extra punch to really make your songs, games, and movies come to life.

Diminutive yet Perfect to Behold

The all-aluminum black body has been painstakingly CNC-machined, anodised, and sandblasted to ensure that the K3 feels robust yet perfectly textured for a great feel in your hands. The diminutive K3 is portable and a pleasure to hold in your hands, to slot in a purse, or even the jeans pocket.

A distinctly cohesive tactile audiovisual experience

The volume knob, with 45° notches etched onto its surface and perfectly sized to allow easy one-finger operation, is designed to perfectly blend in with the curves of the K3’s body. Next to the volume knob is an RGB light which visually shows you what kind of digital audio being relayed through the K3.

Two modes for many situations

USB Audio Class 1 and Class 2 are interchangeable with just the flick of a switch. In high-performance applications, you can use the 2.0 mode to enjoy up to 384kHz/DSD 256 decoding. In certain situations, you can use the 1.0 mode to enjoy up to 96kHz/24-bit PCM audio without needing any drivers.

Dual headphone jacks

Being optimised for indoor desktop use, the K3 is equipped with both 3.5mm single-ended and 2.5mm balanced headphone jacks. Both outputs have audio jack detection, which means that when headphones are inserted into the balanced out, balanced boost automatically kicks in resulting in about a 50% output power increase compared to the single-ended out.

Line out connector

The 3.5mm line out is driven directly by the OPA1612 op-amp, to ensure as little sound quality reduction as possible. The line out output is also adjustable with maximum power output up to 2Vrms, ensuring the compatibility with a wide variety of active speakers and external amplifiers.

Coaxial and Optical digital outs

The XMOS USB receiver chip in the K3 directly converts any USB audio input to digital signals output via the coaxial and optical connectors, allowing a connection to speaker systems, amplifiers, or other external decoders.


USB: Type-C
USB Audio Class: UAC1.0 + UAC2.0
Volume Knob: ADC
Gain: L/H
Bass Boost: 0/+6dB
Line Out: 3.5mm
Headphone Out 1: 3.5mm 
Headphone Out 2: 2.5mm
Coaxial Out: RCA for 192kHz, support DSD64 DOP
Optical Out: Up to 96kHz 
Audio DAC: AKM AK4452
Driver OP AMP: OPA926×2
Output Power 1 (3.5mm headphone output): 220mW(16Ω) / 120mW(32Ω)
Output Power 2 (2.5mm TRRS balanced headphone output): 320mW(16Ω) / 200mW(32Ω)
Line Level: 1.9Vrms
DAC: 384kHz/32bit
SNR: ≥113dB
THD+N: ≤0.004%
Frequency Response: 20Hz-80kHz
RGB indicator: Sample rate ≤ 48kHz  – Blue / Sample rate >48kHz – Yellow / DSD format – Green
Dimensions: 70×58×22mm

Pricing and Availability

The FiiO K3 is available at a recommended retail price (RRP) of S$189 (including GST) at authorised retailers including AV One, Connect IT, Stereo Electronics, E1 Personal Audio and

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