FiiO K9 PRO Desktop DAC/Amp


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Note: K9 Pro AKM version was a limited edition product and is now sold out. K9 Pro ESS version is in-stock and shipping now.

FiiO flagship now with dual ESS DAC chips

The FiiO K9 Pro Desktop DAC/Amp has become a huge hit thanks to overwhelmingly positive reviews from YouTubers like DMS and Joshua Valour. (Check out those reviews below.) It featured an AK4499 DAC chip that was in short supply to begin with, due to the fire at the AKM factory in 2020, and is now completely sold out.

Now, FiiO has pivoted to using dual flagship SABRE ES9038 PRO DAC chips by American manufacturer ESS. (The original featured a single chip.) Read our deep dive into the differences between the models.

Dual ESS SABRE ES9038PRO DAC chips

Dual ES9038PRO DAC chips take the K9 Pro to new heights, achieving better THD+N and SNR than its predecessor.

Exemplary dual THX AAA Amps

The pair of THX AAA 788+ chips used in the K9 Pro ESS provides exemplary details and dynamics for both low and high-impedance headphones. The K9 Pro ESS can output up to 46Vpp transients when driving high-impedance loads, and up to an undistorted 2W when pushing low-impedance loads.

Dual femtosecond clocks

Using an ultra-precise clock management system, the K9 Pro ESS can maintain maximum quality no matter the source. Dual asynchronous femtosecond clocks are used to decode USB and Bluetooth sources, while automatic PLL clocks are used to decode optical and coaxial sources.

Hi-res Bluetooth

The K9 Pro ESS employs the Qualcomm QC5124 to handle Bluetooth duties, with support for formats such as LDAC, aptX HD and aptX Adaptive. This chip ensures that Bluetooth connections are both reliable and quick, satisfying both the low latency needs for games/videos and the high bitrate necessary for high resolution audio.

Flawless volume adjustment 

The volume knob may seem like a pretty simple component of an amp, but executing it well is crucial to the listening experience. The ADC curve reconstruction method of volume adjustment used in the K9 Pro ESS effectively minimizes any left-right channel volume imbalance and noise. It also results in a smooth change of volume across all levels.

3-way gain adjustment

Switch between low, medium, and high gain to accommodate your entire headphone library. Thanks to a pure hardware gain circuit, the K9 Pro ESS maintains the dynamic range and fidelity of your music even while amplifying high-sensitivity headphones at low gain.

Utterly elegant UI

Controls are clearly and intuitively laid out for an effortless experience. Metal switches are used for controlling input selection and gain level.

Light it up

The RGB indicator lights surrounding the stainless steel volume knob change colors depending on the currently playing sample rate.

Take control

Built-in Bluetooth low energy technology allows you to use the FiiO Control App to control functions like channel balance, sleep timer at any time, even when not in Bluetooth mode.

Product highlights 

  • Dual ESS SABRE ES9038 PRO chips
  • Dual THX-AAA 788+ amplifiers
  • Dual femtosecond clocks
  • Qualcomm QCC5124
  • Supports LDAC, aptX adaptive, aptX HD
  • App control
  • Truly balanced design
  • Dual voltage linear transformer
  • Wide connector selection
  • Lossless MQA decoding
  • Bluetooth format indicator


  • DAC chip: ESS SABRE ES9038PRO x2
  • USB chip: XMOS XUF208
  • Bluetooth chip: Qualcomm QCC5124
  • Amp: THX-AAA 788+ x2
  • Linear transformer: THAILIN/BingZ
  • Gain: L/M/H
  • Supported Bluetooth codecs: AAC, SBC, aptX, aptX LL, atpX HD, LDAC, aptX adaptive
  • Maximum supported sampling rates
    • USB DAC: 32-bit/384kHz, DSD256
    • Coaxial: 24-bit/192kHz
    • Optical: 24-bit/96kHz
  • Recommended headphone impedance: 16-600Ω
  • USB: Type-C, USB B (data transmission)
  • Inputs: RCA, 4.4mm balanced, optical
  • Outputs: 4.4mm balanced, XLR, 6.35mm, RCA
  • Weight: 6lbs (2750g)

Single-ended line out parameters

  • THD+N: <0.00042%
  • SNR: ≥123dB
  • Crosstalk: ≥115dB
  • Noise floor: <1.9uV
  • Frequency response: 20Hz - 20kHz
  • Line level: 2.5Vrms

Balanced line out performance parameters:

  • THD+N: <0.00025%
  • SNR: ≥128dB
  • Crosstalk: ≥125dB
  • Noise floor: <1.9uV
  • Frequency response: 20Hz - 50kHz
  • Line level: 5Vrms

Single-ended headphone output parameters:

  • Continuous undistorted output power 1: ≥1.2W (16Ω/ THD+N< 1%, Aux in)
  • Continuous undistorted output power 2: ≥2W (16Ω/THD+N<1%,UAC/SPDIF/BT IN)
  • Continuous undistorted output power 3 : ≥281mW (300Ω/ THD+N< 1%, Aux in)
  • Output impedance: <1Ω
  • Crosstalk: ≥75dB
  • THD+N: <0.00033%
  • Noise floor: <2uV
  • SNR: ≥129dB
  • Frequency response: 20Hz - 50kHz
  • Max output voltage: >26Vp-p

Balanced headphone output parameters

  • Continuous undistorted output power: ≥1.1W
  • Output impedance: <1Ω
  • Continuous undistorted output power 2: ≥2.1W (32Ω / THD+N < 1%, Aux in)
  • Continuous undistorted power 3: ≥1.1W (300Ω/ THD+N <1%, Aux in)
  • Noise floor: <3uV
  • Frequency response: 5Hz - 50kHz
  • Output impedance: <1Ω
  • Crosstalk: ≥114dB (1kHz, Aux in)
  • THD+N: <0.0003%
  • SNR: ≥123dB
  • Max output voltage: >52Vp-p

What pairs well

Featured reviews

"Incredible....great build quality, great sound quality...absolutely worth the asking price." -Joshua Valour

"My favorite DAC/ all-in-one, no compromise solution." -DMS

"The only DAC/amp you'll ever need." -Home Studio Basics

Professional Product Review of FiiO K9 PRO Desktop DAC/Amp

FiiO K9 PRO Desktop DAC/Amp User Manual Download

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