The FiiO K9 AKM review sample was kindly provided free of charge. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links. The price of the FiiO K9 AKM is $530 and you can buy it from FiiO.eu.
FiiO K9 AKM Review
The K9, an all-in-one desktop DAC and headphone amplifier from FiiO, falls into the mid-range category. It serves as a smartly positioned model between the pricier FiiO K9 Pro ESS and the more affordable FiiO K7. Initially, the FiiO K9 was launched with dual ES9068AS DAC chips and THX AAA 788+ amplifiers. However, FiiO decided to introduce a new version with an AKM DAC chip, giving birth to the FiiO K9 AKM which comes at a $30 higher price point compared to the ESS version.
Technical highlights
The FiiO K9 AKM distinguishes itself from the K9 with its use of an AK4191+AK4499EX DAC chip combo by AKM, as opposed to the dual ES9068AS by ESS found in the original K9. Despite this change, all other components remain identical. The balanced amplifier still utilizes dual THX AAA 788+ modules, providing the same power output as the original K9. Two OPA1612 chips handle low-pass filtering, two OPA1602 chips act as buffers, and the volume IC is the NJU72315.
The K9 AKM’s PCB features a partitioned layout, effectively isolating the power supply, signals, and analog signal loop. A toroidal transformer and 4 large 4700uF capacitors make up the linear power supply, ensuring a steady flow of clean power. Additionally, the digital and analog sections of the K9 AKM are powered separately to minimize interference between the two circuits.
Equipped with an XMOS XUF208 decoder featuring dual-clock management, the FiiO K9 AKM supports up to 768kHz/32bit PCM and DSD512. A circular RGB light around the volume knob indicates the input sampling rate.
You can read more information here.
Bluetooth connectivity
The K9 AKM utilizes the QCC5124 Bluetooth chip, which supports LDAC/aptX HD/aptX Adaptive and other Bluetooth codecs. This allows for wireless reception with exceptional audio quality. While it may not match the audio quality provided by wired digital inputs, the Bluetooth connectivity remains stable and offers a competitive audio experience. This feature is especially beneficial in situations where wired connections are not available.
FiiO Control application and EQ
The FiiO Control application enhances the functionality of the K9 AKM, offering access to a wide range of settings. These include adjusting digital filters, status indicators, EQ, and channel balance. Additionally, the EQ of the K9 AKM features 7 pre-set music tuning styles, with the option to customize the PEQ and save adjustments in one of three memory slots. It is important to note that the EQ function is only active in Bluetooth reception mode. Thanks to support for the low energy Bluetooth protocol, users can still utilize the FiiO Control application even when Bluetooth is disabled.
Design and build quality
The AKM version’s design mirrors that of the original model. The FiiO K9 AKM has a sturdy and well-crafted all-aluminum chassis with a sleek black matte finish. Its compact size allows for versatile placement, and it can even be positioned vertically using the provided stand.
Layout and connectivity
The FiiO K9 AKM features a side mounted USB type-C port, which is a notable addition compared to the regular K9 model. Except for the USB type-C port, the digital inputs of the FiiO K9 AKM include USB type-B, optical, coaxial, and Bluetooth options. Moreover, the FiiO K9 AKM offers stereo RCA and balanced 4.4mm line inputs, allowing you to connect analog sources and utilize it as a standalone headphone amplifier.
To conveniently display the selected inputs, the FiiO K9 AKM is equipped with five LED lights positioned in the upper right corner. Input selection, gain setting, output mode, and power standby/mute functions are controlled using two buttons and two switches.
At the front of the FiiO K9 AKM, you will find three headphone outputs: 6.35mm, 4.4mm, and 4-pin XLR. Additionally, there are stereo RCA and balanced XLR line outputs located at the back of the device. The FiiO K9 AKM supports three output modes: headphone out, pre-out, and fixed level line out.
Accessories
The bundle comprises of a power cord, six adhesive feet, a spare fuse, the vertical stand, a USB data cable, and a 3.5mm headphone adapter. The device is equipped with rubber plugs for the USB type-C and 4-pin XLR inputs to safeguard them from dust when they are not being utilized.
Power output and associated gear
The FiiO K9 AKM headphone amplifier offers three gain levels (low, medium, high) to accommodate different headphone loads. It is designed to deliver 2Wpc/32Ω or 780mWpc/300Ω from its balanced output, and 1.5W/32Ω or 200mWpc/300Ω from the 6.35mm output. This provides sufficient power for most headphones, although some very challenging models like the HIFIMAN Susvara may require more. The amplifier pairs well with headphones such as the FiiO FT5, HIFIMAN Arya Organic, and Sennheiser HD660S2. Additionally, the background noise is virtually non-existent, even when using highly sensitive earphones like the FiiO FX15. The FiiO K9 AKM underwent a burn-in period of 100 hours before critical listening tests, with all cables being pure silver Lavricables.
Listening impressions
Sound comparisons with the FiiO K9 are embodied in the following text.
The question that has to be answered is whether the use of another DAC chip, while keeping everything else unchanged, can result in a significantly different sound for the AKM version compared to the original. The response to this question is twofold: yes and no. These two variations of the K9 do indeed have their own sonic personalities, but they also possess certain shared traits.
The FiiO K9 AKM boasts exceptional sound quality that surpasses its price point, ensuring a satisfying listening experience regardless of your music preferences or choice of headphones. This neutral DAC/amp delivers excellent tonal balance, undeniable transparency, and impeccable fidelity. Its crystal-clear and well-defined sound, coupled with competitive technicalities and robust driving force, guarantees an immersive audio experience.
The K9 AKM excels in producing deep bass that is both fast and controlled, with remarkable inner clarity and impressive layering. Its dynamic and impactful performance showcases full-bodied and weighty textures. While the THX amplifiers slightly limit the perceived spaciousness and the bass lacks resonance, the AKM version outperforms the K9 in these aspects. The AKM offers enhanced atmospheric sound and a more immersive listening experience.
The K9 provides better clarity and overall technical performance and is also more disciplined with a faster decay compared to the AKM. However, it may sound slightly drier, leaner, and less full-bodied than the latter.
More listening impressions
The mid-range offers an open, present, and tonally balanced sound that is crystal clear and well defined. The sound temperature is neutral with a slight shift towards warmth compared to the K9. The K9 AKM delivers more colorful harmonies with greater overtone diversity than the K9, providing a more natural and realistic timbre, along with richer and rounder textures. The AKM DAC chip helps to counterbalance the academic sterility of the THX modules, offering a more musical and engaging sound signature. However, the ESS version stands out as the most technically advanced, providing finer resolution and superior mid-range clarity, transparency, and articulation.
The AKM version exhibits a more natural and effortless treble sound compared to the K9, which is characterized by a bit brighter and more academic tone. The AKM version offers extended and energetic treble with plenty of airiness and light, although not as sparkling and luminous as the K9. The K9, on the other hand, is more resolving and provides deeper detail extraction, but it may come across as slightly brighter and less musical. Additionally, the K9 is faster and more vibrant, while the AKM version is more relaxed and blunt. Overall, the AKM version is perceived as slightly more musical than the K9, although it may lack the transparency and cleanliness of the latter.
And more…
The soundstage of both units offers a sense of openness and spaciousness, along with impressive extension and layered depth, particularly noticeable in their balanced outputs. The AKM unit provides a slightly more holographic, atmospheric, and immersive experience, while the ESS K9 excels in imaging precision and pinpoint positioning, creating unmatched accuracy. Nevertheless, it is important to highlight that the sound disparities between these two devices are not in a night and day fashion. Each unit has its own distinct and easily recognizable personality, yet they also share numerous common traits.
Not only for your headphones
In this section I am literally copying myself from the original FiiO K9 review:
“The FiiO K9 AKM delivers consistent high-quality audio performance through both the headphone and line outputs, making it a versatile option for use with headphones, powered monitors, or as a standalone DAC. Additionally, the transparent headphone amplifier accurately reproduces the sound characteristics of an external analog source without adding any coloration. The FiiO K9 AKM stands out as a top-tier desktop audio source suitable for a wide range of applications.”
Vs the FiiO K7
The FiiO K7 BT is a compact and budget-friendly option for those seeking a desktop DAC/amp with balanced circuitry and AKM DAC chips. Equipped with two AK4493SEQ DAC chips and dual THX AAA 788+ amplifier modules, it can deliver 2Wpc/32Ω from the balanced output, the same with the FiiO K9 AKM. But the more robust internal power supply of the latter, allows it to provide 780mWpc/300Ω compared to the K7’s 560mW, making it better suited for high impedance headphones. Additionally, the FiiO K7 lacks a balanced XLR output and a 4.4mm line input.
The K9 AKM stands out in terms of sound quality compared to the K7 as it offers enhanced dynamics and impact, along with a deeper, clearer sound. It provides superior transparency and clarity, resulting in a finer, more resolving audio experience. Moreover, the sound is smoother and more effortless, with a less sterile treble and minimal digital glare. Overall, the timbre is more natural and realistic with the K9 AKM so if you have the space and the budget, it is worth investing in it.
In the end
The AKM version of the FiiO K9, just like the original, offers an exceptional level of audio quality and a wide range of connectivity options, all at an unbeatable price. What sets it apart from the ESS K9, is its slightly smoother, warmer, and more natural sound, which adds a touch of variety and avoids sounding too technical or academic. Despite these differences, it still maintains a high level of transparency and technical prowess. With two equally delicious flavors to choose from, the user can now enjoy the option of either the plain K9 or the AKM version. Whichever one you choose, rest assured that you’ll be getting an excellent all-in-one desktop DAC/amp with an incredible price-to-performance ratio.
Copyright – Petros Laskis 2024.
+ Near flagship audio performance
+ Neutral and transparent
+ Dynamic and impactful
+ Great technicalities
+ Warmer than the ESS
+ More forgiving than the ESS
+ Less sterile and academic than the ESS
+ Natural timbre with minimum digital glare
+ Powerful enough
+ Spacious and open soundstage
+ Plenty of inputs and outputs
+ User customizable EQ
+ Great value for money
+ Excellent build quality
+ Compact and can be vertically positioned
+ Accessories
- No remote control
- EQ is only effective in Bluetooth mode
- Not as technical and transparent as the ESS K9
- Not the same level of clarity and detail retrieval as the ESS
- $30 more expensive than the K9
- Still not that atmospheric and organic as the competition
- Competition can be more powerful
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