FiiO K9 AKM Review


In this article, we review FiiO’s revised all-in-one unit, the FiiO K9 AKM. It retails for $529.99 USD. 


Disclaimer: FiiO provided the FiiO K9 AKM for this review at no cost. As always, the article reflects my unbiased opinion.

FiiO Company

Known for its dedication to designing high-quality audio equipment, FiiO is a cornerstone of the global audiophile community. Since its launch in 2007, FiiO has specialized in the design and development of a wide range of audio products at all price brackets. With an extensive distribution network spanning continents, FiiO continues to deliver innovations that resonate with music enthusiasts worldwide. Today, we will take a closer look at one of FiiO’s latest offerings, the K9 AKM, an enhanced and upgraded version of their highly regarded K9 DAC & AMP.

Over the years, we have reviewed and awarded a lot of FiiO equipment on Headfonia. You can access those reviews through this link: Headfonia FiiO Reviews.

FiiO K9 AKM Desktop DAC and Headphone Amplifier with Bluetooth

The K9 AKM’s product web page can be found here. It costs $529.99 USD from FiiO’s official AliExpress Store. AliExpress holds several annual discount weeks, and it can be picked up for 480-ish USD with discounts depending on your region. Here’s a list of specifications and highlights of the FiiO’s new king in the midrange DAC/AMP sphere.

  • AKM AK4499EX + AK4191EQ Flagship DAC
  • Dual THX AAA 788+ Amp Modules (≈2W @32Ω)
  • Dual-Voltage Linear Transformer PSU
  • Fully Balanced Architecture
  • Isolated Digital & Analog Power
  • Dual-Mode Jitter Clocks, 4700uF caps, multiple LDOs
  • 3rd Generation XMOS XU-308 USB Controller
  • Qualcomm QCC5124 BL Chipset
  • Bluetooth 5.1 + LDAC 24bit/96kHz, APTX/HD, SBC, AAC
  • 32bit 768kHz PCM & DSD512 Support
  • Upgradeable Firmware + UAC 1.0 & 2.0 Modes for PS5 etc.

A while ago, we took a closer look at the K9 and were quite impressed with its performance. The K9 is positioned between the K7 BT and the K9 Pro, and in this article, we are taking a closer look at the K9 AKM. The K9 AKM is 30 USD more expensive than the K9 and shares many similarities with it. Also, the entire K9 line, including the K9 AKM, uses the same chassis as the K9 Pro ESS. 

FiiO’s K series currently consists of eight desktop all-in-one devices. The latest variants are the K5 Pro ESSK7 BTK9, K9 AKM, K9 Pro ESS and K19. You can click on each unit’s name to go to its Headfonia review. Also, stay tuned for the new K19 review that is coming soon!

What’s New?

The FiiO K9 AKM introduces several upgrades over its predecessor, the K9, enhancing functionality and user experience. At the heart of the K9 AKM is the adoption of a flagship DAC, the AKM 4499EX, and its accompanying delta-sigma modulator, AK4191Q, providing superior audio compared to the K9’s Dual ES9068AS DAC chips. Another notable addition is the USB-C port located on the side. The K9 was limited to USB-B only. Side USB-C not only facilitates easier connection with smartphones without the need to reach the back of the device but also serves as an alternate USB input that can double as a port for firmware upgrades. Additionally, the K9 AKM features a redesigned front panel with more noticeable laser printing and a new THX sticker with gold accents.

Here’s a quote from AKM about the 4499-4191 pair:

Nakamoto: The AK4191 audio interface operates in synchronization with the audio clock, and the AK4499EX, which performs D/A conversion as the second stage of the AK4191, can perform high-precision D/A conversion by using a different low-jitter clock. For example, when streaming data is played back, even if the clock rate of the data that is sent and the clock rate of the data to be run in the DAC do not match, high-precision D/A conversion is enabled. 

Chubachi: During data conversion, unwanted components called image components are also generated. The image components are handled by realizing stopband attenuation capacity of 150dB with the digital filter of powerful computation equivalent to a sampling rate converter. Having this filter in the digital chip also suppresses noise from asynchronous operation, resulting in analog characteristics with no degradation. 

If you want to read more about the AKM company’s flagship DAC, you can visit this webpage. The main difference between the K9 and the K9 AKM is the sound. Some of this review will, therefore, be similar to the K9.

Packaging & Accessories

The FiiO K9 AKM is presented in the distinctive packaging style that FiiO has been using since 2021. This packaging style can also be seen in models such as the K9 Pro ESS, K7 BT, and K5 Pro ESS. The exterior of the packaging features a rainbow-effect coating, matching FiiO’s futuristic design philosophy.

The unit is housed in a large, hinged box with an illustration of its outline on the front. The VelvetSound and Hi-Res certification badges are placed in the far right corner. Upon opening the box, the first thing you encounter is a WARNING leaflet. This important notice warns the user that the product contains a linear power supply and that the local mains voltage MUST be set manually using a switch on the bottom. This is a critical step, as selecting the wrong voltage can damage the unit.

A large accessory box is placed next to the unit beneath the foam top cover. This is where the true size of the K9 AKM first becomes apparent. It is not the most compact of its competitors, but its size is justified by its versatility as an all-in-one solution for many audio needs. The included accessories are comprehensive: a power cable, a spare fuse, a USB-A to USB-B cable, a Bluetooth antenna, six adhesive rubber feet, a vertical stand, a 6.35mm headphone adapter, and a user manual.

The standout accessory is undoubtedly the vertical stand. Not only does it allow the unit to be used as a headphone stand, it allows it to be positioned vertically, saving space on the desk. In my opinion, this feature enhances the overall aesthetics of the device, as I really like the vertical look.

Design & Build Quality

The K9 AKM shares its design with the K9 and measures 20 x 22 x 7 centimetres. Although not particularly small, its size is justified by its all-in-one functionality, and the inclusion of a vertical stand adds to its practicality. The unit’s internal layout and circuit board are packed with high-quality audio components, displaying FiiO’s meticulous use of space.

The aluminum enclosure is similar to FiiO’s range of digital audio players but with more refined and elegant design elements. The case is precision machined and finished with a sandblasted matte black coating for a sleek yet robust look that will appeal to any audio enthusiast. The build quality is exemplary. It is sturdy, durable, and meticulously assembled. Details such as the RGB LED under the volume knob, radiant design buttons, and a radiant design black volume pot add to the premium aesthetic.

The design of the unit is simple and functional, combining elegance with a professional feel. The front panel includes essential controls, multiple headphone outputs (3.5mm, 4.4mm, and XLR 4-pin), volume pot, and status LEDs. Although there is no remote control, the FiiO Control app, available for both Android and iOS, provides remote volume control for added convenience in select modes.

Looking at the back, the K9 AKM is equipped with a variety of I/O options to suit different needs. These include an IEC C13 power socket, Bluetooth antenna socket, USB-B input, and multiple audio inputs and outputs, including coaxial, optical, unbalanced RCA, and balanced XLR. Also, there is a 4.4mm input on the back, a rare feature in this price range. The connectors, including gold-plated RCA and XLR, are of high quality with no visible defects or imperfections.

Additionally, like the K9, the K9 AKM features strategically placed ventilation holes to cool internal components like the THX amp modules and the transformer. Here’s some information about the volume pots of the K series; the K9 Pro ESS version is equipped with a golden volume pot, and the K9 Pro AKM version comes with a black volume pot decorated with a chrome outline. The K9 and K9 AKM use an all-black pot with radiant design cues on its center. In conclusion, the FiiO K9 AKM impresses with its design and build quality, meeting high expectations in both aesthetics and functionality. 

Technology & Audio Circuitry

The K9 AKM uses AKM’s flagship DAC chip, the AK4499EX+AK4191Q combo. The K9 series is, in my opinion, what put FiiO back into the highlights of the desktop game, and for a good reason. These units are massive, and every inch of the PCB inside is packed with quality components. 

The K9 AKM is fully balanced and has a partitioned layout that completely separates vital parts of the audio circuitry, such as the power supply. While we’re on the subject, the K9 series is the first series I’ve seen from FiiO that uses a full-size linear transformer. (accompanied by four massive 4700uF capacitors) The digital and analog parts of the K9 AKM are separated, similar to the AK4499EX and 4191Q. 

FiiO uses a six-stage audio circuit that took over a year to develop and refine. There are LDOs across the stages to regulate power, dual clocks to reduce jitter, and much more that we can’t see. These may be overkill, but for the price, you get a very overkill unit that will make you happy in terms of sound. I see the K9 series as FiiO’s ‘this is how it’s done’ series, showing the market what kind of performance can be achieved with proper implementation and quality components. 

On the amplifier side, the K9 AKM features two THX AAA 788+ modules along with OPA1612 and OPA1602 operational amplifiers, similar to the rest of the K9 series, developed in collaboration with THX and FiiO. The K9 AKM is capable of delivering 780mW at 300 ohms and 2000mW at 32 ohms. From a purely technical point of view, FiiO’s engineering team seems to have outdone themselves.


The article continues with the part on sound on the next page. Click here or use the buttons below.

Page 1: FiiO, K9 AKM, Packaging & Accessories, Design & Build Quality, Technology & Audio Circuitry,

Page 2: Controls & Operation, Comparative DAC Performance, Comparative DAC/AMP Performance, Wireless Performance, Last Words

4.4/5 - (296 votes)

Long time Tech Enthusiast, an ambitious petrol-head, Yagiz likes his gadgets and always finds new ways into the tinkerer's world. He tries to improve anything and everything he gets his hands onto. Loves an occasional shine on the rocks.

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