FiiO K19 Review featured image

FiiO K19 Review

In this feature, James reviews the FiiO K19, which is a new flagship desktop integrated DAC and balanced dual THX AAA-788+ headphone amplifier with PEQ capability. It is priced at $1349.99.

Disclaimer: This was sent to me as a sample in exchange for my honest opinion. Headfonics is an independent website with no affiliate links or services. I thank FiiO for its support.

You can click here to learn more about the FiiO audio products we have previously assessed on Headfonics.

Note, that this post follows our current scoring guidelines which you can read in more detail here.

FiiO K19 Review featured image
FiiO K19 Review
The FiiO K19 serves as a comprehensive, all-in-one desktop DAC and headphone amplifier for users seeking impressive audio performance, compatibility with consoles and various sources, and who also possess a diverse collection of headphones.
Sound Quality
Slide here to add your score on the gear!68 Votes
Excellent power
Very useful and effective PMEQ option
Coherent sound signature
Small screen can be hard to read at times
No USB-B input
Award Score

In this feature, we will be reviewing the FiiO K19, FiiO’s latest flagship desktop amplifier and decoder with a futuristic and flexible design, priced at $1349.99 SRP.

This sleek device challenges the notion that bigger equals more power, delivering a serious punch with significantly higher output power compared to the more muscular-looking K9 AKM and K9 Pro ESS.

With dual 8-channel decoders and 8-channel THX AAA-788+ amping modules inside this is created to drive virtually any set of headphones. FiiO even adds a professional 31-band PEQ option to further enhance its flexibility.

Does it offer a significant improvement for headphone users over the previous K9 series of desktop amp/DACs? Let’s find out in my full review below.

FiiO K19 on its stand

Tech Highlights


The K19 is packed with a dual ESS SABRE ES9039SPRO DAC implementation allowing for decoding at up to PCM 32-bit 768kHz and native DSD512.

Furthermore, to ensure precise clock signals and lower jitter, the DACs are accompanied by FPGA-controlled, dual ACCUSILLON AS318-B ultra-low phase noise femtosecond crystal oscillators, clocked at 45.1584MHz and 49.1520MHz.


The FiiO K19 incorporates two THX AAA-788+ amplification modules connected in a 2×2 array. The circuit outputs an impressive 8000mW per channel, which makes it the most powerful desktop amplifier I have reviewed to date.

The output impedance is rated <0.6Ω which is satisfactory and allows this powerful beast to be paired with sensitive gear without impedance skew.

FiiO K19 PEQ equalizer


The K19 has a built-in PEQ system which is powered by a SHARC+ processor ADSP-21565 DSP from Analog Devices Inc. with a dedicated oscillator HDC970X clocked at 16.384MHz.

To use the PEQ, you will need to download FiiO’s DSP software and then configure the equalizer on a PC/Mac or via an iOS/Android application and connect via the RS232 port.

This intuitive feature allows experienced users to share pre-saved PEQ profiles from other PEQ software for optimizing dedicated gear, with pin-point multi-band EQ that can be applied to many purposes like correcting headphone/speaker response or for room correction.

There is even a real-time analyzer that shows the level of the content being played so you can have a good clue where to boost.

A good hardware EQ could be a game changer, as it allows for fine-grained adjustments on the output tonality and can correct room acoustics for speaker systems.

FiiO K19 paired with FiiO FT5


The K19 is a desktop component with a die-cast unibody aluminum alloy frame polished with CNC machining and is incredibly thin at 36.7mm.

There are numerous heat-dissipation holes opened on the body and you can see honeycomb grills resembling those on the side panels of the R9, providing effective heat dissipation while exuding a futuristic look. These grills efficiently block dust and dirt, although occasional vacuuming may be necessary.

You can use the K19 vertically or in landscape mode, and the squared 1.3” screen on top can be configured to point to 0°, 90°, 180° or 270°. While it is reasonable to use a squared small screen so it can be rotated to different angles I hope it can be slightly larger and allows changing the navigation direction when turning the knob.

FiiO also comes up with an aluminum alloy stand with a screw-on locking mechanism which is designed for shock absorption, unlike the plastic rest that comes with the K9 Pro ESS.

The upright design of the K19 is straightforward, allowing it to be placed alongside bookshelf speakers and save desk space.

The addition of the ring of light around the buttons adds a cool touch, especially in low-light conditions. However, I do hope that FiiO considers incorporating special effects like breathing lights or customizable color options in the control menu.

FiiO K19 rear panel


The FiiO K19 is versatile in connectivity, covering digital inputs from classic SPDIF/COAX to modern USB-C and both balanced XLR and unbalanced dual RCA analog outputs on the rear panel. On the front panel, it has both SE 6.35mm and balanced XLR and 4.4mm outputs.

Aside from the essential connections needed for a home scenario, the K19 also includes the convenient HDMI ARC port that simplifies connectivity with supporting devices for gaming and TV setups.

Additionally, the front panel features a USB-C port, allowing easy connection to other devices such as DAPs or laptops for configuring the equalizer, without the need to access the rear part panel.

The FiiO K19 features a switch on the rear panel that enables users to select the power supply mode, either 220V AC mains or 15V DC, catering to different configurations.

It also incorporates a ground lift switch on the back panel, providing a solution for combating ground loop issues that arise from interconnecting audio devices with varying power sources or grounding potentials that introduce noise.

FiiO K19 ground lift switch



The K19 upgrades to the Qualcomm QCC5125 solution feature a bi-directional Bluetooth chip, enabling it to support the following wireless transmission codecs: SBC, AAC, aptX, aptX HD, aptX adaptive, and LDAC.

This allows users to switch between low latency or to enjoy optimized transfer quality over the air.

When connected via Bluetooth you can use both the volume on the source as well as the volume knob on the K19. The Equalizing and filtering features also apply to Bluetooth input.


The FiiO K19 can be connected to Windows and Mac PCs without USB drivers. The decoder supports up to 32bit/768kHz and DSD512 decoding on USB which is higher than the 24bit/192kHz and DSD64 support on Coaxial input.

You can connect the K19 to your computer or other devices supporting USB audio using either the USB-C port on the front panel or the one located at the back, which is convenient if you want to play the songs on your DAPs/phone/iPad.

FiiO K19 screen


You can control the K19 via its comprehensive manual onboard controls with some additional options available via the FiiO Control App.

Navigation on the K19 is quite straightforward with the two knobs or by app control, so I don’t think there is a need to read the user manual.

As you may have guessed, the volume knob doubles as the on/off button and the other knob allows the user to navigate through the menu. Simply twist it to change between sources or press it to enter the settings. Different filters and on-board EQ presets can be tweaked in seconds.

If you want to turn off the lights around the knobs, you can use the FiiO Control App which also allows switching between input sources, selecting the Bluetooth Codec, and controlling the multi-band equalizer.

Infrared Remote

Inside the package, there is also an infrared remote controller that does not require pairing like Bluetooth remotes.

This also suggests that you can use phones with infrared features to control the amplifier and this is a great feature if you are placing the K19 across the living room.

12V bi-directional trigger

The FiiO K19 also includes an uncommon TRIGGER feature that offers both active (TRIG OUT) and passive (TRIG IN) modes. This feature is accessed through two 3.5mm jacks on the device.

The TRIG OUT mode allows the K19 to send a trigger signal to other compatible devices for synchronized power on/off control. On the other hand, the TRIG IN mode enables the K19 to receive trigger signals from other devices.

Packaging & Accessories

The overall product experience with recent FiiO products is highly satisfactory, thanks to their high-quality prints, detailed documentation, a rich selection of accessories, and adequate protection.

The K19 comes in a large box that evokes memories of purchasing a 19″ PC monitor in years past.

Inside the box, you will find a remote, a 2-pole 3.5mm-3.5mm cable for the TRIGGER feature, USB-C to USB-A cable, USB-C to USB-C cable, screws and screwdrivers with the stand parts, USB-C to USB-A convertor, 3.5mm to 6.3mm convertor and rubber legs for landscape placement.

FiiO also includes a clip-on part that can convert the K19 into a headphone stand. This is a genius design that won’t heat up the headphones as it barely touches the K19’s body and helps save up more space on the desk.

FiiO K19 paired with FiiO FT5 from the front

Sound Impressions

The K19 is burnt in for around a week and the below impression is based on USB input from the R9 as a source combined with various IEMs and headphones, including the FiiO FT5, HIFIMAN Ananda Nano, Moondrop Venus, and the Westone MACH 20.


FiiO’s K19 is specifically designed for desktop listening scenarios, catering to users who connect wired or wirelessly to computers, digital players, HDMI, smartphones, and other sources to drive almost all cans of different impedance/sensitivity.

With 8000mW @32Ω per channel output power, it behaves more vividly and dynamically than other THX-amp-equipped devices I tried before.

The midrange sounds more vibrant while retaining a strong sense of control and precision with the THX amplification. You can hear the stronger power, not only from the volume but from the solid punch and dense bass coming from insensitive planar headphones or open-back dynamic cans.

The stock tonality is slightly V-shaped but not clinical though PEQ fans might want to dip into this feature to tweak it a bit more.

With USB-in, the definition is the best of the K19 digital inputs with superior treble extension. Testing with the R9 as the source, optical input sounds slightly cleaner in the mid-bass, while coaxial is more colored and forward in the mid-bass.


With ample power, the FiiO K19 displays clean, weighted, and powerful bass. It also allows for easy detection of sub-bass frequencies that kick deep and firm with great agility, showcasing ample energy without excessive boominess.

The bass response exhibits good density and dynamics, even when paired with planar headphones and at the highest gain.

It delivers punchy bass slams with a very clean attack that recovers quickly. It adds to the excellent perceived depth while maintaining an uplifting, clean signature at all gain levels.

The defined bass on the FiiO K19 makes it well-suited for live music recordings and genres like EDM, Blues, and Metal, which may sound even more engaging with a small touch using the PEQ in the fundamental bass frequencies.

The electronic beats and basslines are energized with a notable impact and a sense of spaciousness. There is ample weight for drums and bass guitars, without overpowering the output and curtaining the midrange instruments. Instruments are clearly spaced out from each other.


The midrange tuning on the FiiO K19 plays a significant role in creating a transparent and immersive sound signature.

It delivers different voices swiftly without overpowering the edges or thickening the body, allowing the vocals to be well separated and prominently cut through the mix and sounding natural.

With plenty of energy in the upper mids, it captures nuances and delivers them with good clarity without giving a false sense of definition.

The overall tonality remains cohesive and balanced even at the highest gain which offers the vocal more power, and other instruments are harmoniously complementing the vocal performance.

Moreover, guitars and brass instruments benefit from the tuning and sound wet and energized. The vibrance with which these instruments are rendered adds depth and character to the overall output.

The K19 effectively captures and reproduces the qualities and dynamics of various instruments, especially in the upper mids, and it adds to the musicality, openness, and authenticity.

FiiO K19 volume knob


The K19 demonstrates a naturally extended treble response, even at the highest gain. At the lower gain the treble sounds relatively reserved. However, the strong control and dynamics it brings about are noteworthy considering its powerful output level.

The tuning of the FiiO K19 exhibits good intensity in the 5kHz range, offering vocals a distinct bite, enhanced definition, and increased penetration power.

The actual treble range is gently smoothed, effectively preventing harsh sibilance while retaining airy details. It feels as though the stock tuning of the K19 is intentionally designed to be safe, and even with brighter headphones, it maintains good control and dynamics.

I recommend using the Dance preset in the PEQ software as a reference and a starting point, which boosts frequencies around 60Hz and 4kHz.

This adjustment adds more body to the mix while also providing airy sparkles. It effortlessly increases brightness for instruments like hi-hats and cymbals, further enhancing definition and vividness.

Staging & Dynamics

The K19 delivers a clean and dense output, offering a wide and spacious soundstage and allowing for precise instrument placement and a good sense of depth and separation.

Vocal imaging is decent and stereophonic without being overly sharpened. Reverbs and harmonics are revealed that add to the naturalness and sense of space. The depth can be clearly conveyed allowing you to feel the distance of instruments and very accurately locate where the vocal image originates from.

Overall, the staging feels authentic without pushing any particular range over the others. There’s a subtle boost in the upper vocal frequencies that tease out additional sparkle and enhances the overall definition to make it stand out more.

The resolution allows it to maintain a highly dynamic output and resolution with intense, larger ensembles.

Click on page 2 below for my recommended pairings and selected comparisons.

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