FiiO announce the K9 Pro ESS: Flagship Balanced Hi-Res Desktop Headphone Amplifier/DAC

Featuring dual THX AAA 788+ amps, dual ES9038 Pro DACs, XLR Outputs, Bluetooth aptX HD, LDAC, MQA, and support for audio up to 32Bit 384kHz/DSD256 for £699/$849

The K9 Pro ESS is audio specialist FiiO's flagship balanced Hi-Res desktop headphone amplifier/DAC. ​ Featuring dual ES9038 Pro DACs, dual THX AAA 788+ amp technology, multiple inputs/outputs, and Bluetooth 5.0 with support for multiple codecs including aptX HD and LDAC. ​ With MQA support; native playback of audio files up to 384kHz 32Bit PCM/DSD256; the ability to effortlessly drive headphones featuring an impedance of 16 - 600Ω, the FiiO K9 Pro ESS sets a new standard for products in this category.

Expanding upon the connections offered by its sibling, the K7, the FiiO K9 Pro ESS features a wide selection of audio input options, including: RCA, Coaxial, Optical, USB-B, USB-C, and balanced 4.4mm. From an audio out perspective — alongside the 6.35mm single-ended, 4.4mm balanced, and 4-pin balanced XLR headphone connections — the FiiO K9 Pro ESS also features RCA (L/R) line-out as well as balanced 3-pin XLR (L/R) outputs, ensuring compatibility with a host of external devices.

With its dual THX AAA788+ amplification, the K9 Pro ESS is able to effortlessly power headphones with a wide impedance range of 16 - 600Ω. ​ In addition, Low, Medium and High hardware gain levels can be manually selected from the front panel, allowing you to easily adjust the K9 Pro ESS for headphones of various impedances and sensitivities, ensuring a consistent listening experience.

The FiiO K9 Pro ESS features dual high-performance ES9038 Pro DACs — one for each channel of audio — ensuring it delivers an impressively musical, detailed, and expressive sound, whatever the source. Thanks to the dual-clock management of its XMOS XUF208 decoding chip, the K9 Pro ESS ensures incredibly accurate handling of all digital audio files, up to 32Bit 384kHz PCM / DSD256.

To further ensure the highest quality clean audio output, engineers at FiiO have designed the PCB of the K9 Pro ESS with a partitioned layout. Not only is the power-supply kept separate from any audio signals, but analogue and digital audio is also separated to ensure the integrity of the signals being processed. In addition, throughout its truly balanced six-stage audio circuit, audio signals from the left and right channels are also processed separately by the K9 Pro ESS, thereby reducing crosstalk, and ensuring the highest sound quality possible.

Thanks to its on-board Bluetooth, you can easily pair your smartphone, Digital Audio Player (DAP), PC and more to the K9 Pro ESS. ​ Featuring Qualcomm’s QC5124 Bluetooth processor chip, the K9 Pro ESS not only provides a stable, reliable Bluetooth 5.0 connection but — alongside standard resolution AAC, SBC and aptX codecs — also offers support for hi-res wireless codecs, including aptX HD, aptX Adaptive, and LDAC.

The FiiO K9 Pro ESS is available now, priced £699 / $849.

Review samples are available now.



Dual THX AAA788+


Dual ESS ES9038 Pro



Bluetooth Chipset

Qualcomm QCC5124

Bluetooth Version


Bluetooth Receiver

AAC/SBC/aptX/aptX LL/aptX HD/aptX Adaptive/LDAC

Audio Format Support

Up to 384kHz/32Bit (PCM) / DSD256

MQA Support

Yes (8 x Unfold)

Headphone Outputs

1 x 6.35mm Single-Ended

1 x 4.4mm Balanced

1 x 4-pin XLR Balanced


1 x RCA (L/R)

1 x 3-Pin XLR (L/R) (Balanced)


1 x USB-C

1 x USB-B

1 x Coaxial

1 x Optical (TOSLINK)

1 x 4.4mm Balanced

1 x Bluetooth Receiver

Headphone Gain Modes

Low / Medium / High


Headphone ​ Impedance

16 - 600Ω

Frequency Response

20Hz - 50kHz







In The Box

1 x FiiO K9 Pro ESS

1 x Power Cable

1 x Bluetooth Antenna

1 x USB-B to USB-A Cable

1 x 3.5mm to 6.35mm Adapter

1 x Vertical Stand

1 x Quick Start Guide



For further specification, please click here.


Starscream Communications

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