FiiO K9 AKM

General/Build/Packaging
Fiio needs no further introduction. I have tested and reviewed several products from the brand and I have good experience with their products in general. I have their desktop dac/amp with me today, the Fiio K9 AKM which houses AK’s flagship DAC, the 4191+4499EX as well as a plethora of components within the unit itself.
The build quality is very solid and premium looking, no sharp edges and the necessary functions/buttons are located on the front panel, output selector, gain switch, input selector, standby/mute switch are all on the front panel. Volume knob turns smoothly and it feels very controlled, so no sudden jump in terms of volume.
There’s also a side USB C port which in my opinion is a nifty feature whereby when you want to connect your phone or DAP as source, you do not have to reach to the back for the USB B cable instead just use a Type C to C.
The packaging itself is good and nothing to complain about, a USB B to A cable, and also power cord are included, very well protected. There is also a stand that allows you to place the K9 AKM vertically if you’re having some constraint on your desk.
Let’s take a look at the specifications below:



Specifications

• DAC: AK4191EQ + AK4499EX
• Decoding chip: XMOS XUF 208
• Amplifier: Two THX AAA 788+
• Bluetooth chip: QCC5124, Bluetooth 5.1 Bluetooth format support: LDAC/aptX Adaptive/aptX HD/aptX/aptX LL/AAC/SBC
• Outputs: 6.35mm/4.4mm/XLR-4/RCA/XLR
• Inputs: USB/OPT/COAX/RCA/4.4mm
• Output power 1: L+R≥2000mW+2000mW (32Ω balanced/THD+N＜1%)
• Output power 2: L+R≥780mW+780mW (300Ω balanced/THD+N＜1%) SNR: ≥124dB (A-weighted, UAC)
• Noise floor: PO＜8μV (A-weighted, UAC); BAL＜9.3μV (A-weighted, UAC)
• Output impedance: ＜1Ω (32Ω load)
• Weight: approx. 2660g
• Dimensions: 200×224.5x72mm (without feet)
• Comprehensive accessories K9*1, mains cable*1, headphone plug adapter*1, USB data cable*1, feet*6, fuse*1, stand*1, quick start guide*1, voltage selection card*

IEMs/Headphones/Equipments used for this review

• Sony MV1
• Spirit Torino Twin Pulse IEM
• Letshuoer EJ07
• Macbook Air M2 -> Fiio K9 AKM -> Tidal
• Macbook Air M2 -> Fiio K9 AKM -> foobar 2k (tracks ranging from 16-44 to 24-192)

Foreword
My review is solely based on what I hear via my equipment and I never consider my reviews to be objective in any way rather a subjective approach. Do take into consideration that everyone’s ear anatomy is not the same, so the psychoacoustics perception might be different as well, but i believe it will not stray too far

Sound Impression (Slow Filter and no EQ/PEQ USB in Mode)
The K9 AKM has been burned in for approximately 50 hours prior to writing this impression. The sound of the K9 AKM is nothing but amazing. Dead silent background, zero noise. I’m not saying it will make a bad sounding/ badly tuned IEM turn good, it simply makes what is already good a step further and eeking out every bit of hidden potential your IEM/headphone have. The K9 AKM is quite neutral to my ears if you’re using the Fast Filter, i prefer it to be slightly coloured hence i’m using the Slow Filter as stated, there’s a slight lift on the lows, but the overall listening impression to me is that it is natural and the technicalities are very impressive.
Soundstage is largely dependent on the transducers and mastering of the songs, but K9 AKM does render the soundstage very open and let you have a good perception on the stage size in terms of depth, width and height.
Imaging is absolutely excellent with very good separation and layering, instruments can be pinpointed easily and they sound like they each have a space of their own and not mushed together.



Pairings
Letshuoer EJ07

• Pairing the Soloist with the K9 AKM is nothing but fun, the bass is definitely elevated, it has more punch now and better extension, it is tight and the texture is good as well, all these without messing with the mids and highs, this is evident when listening to Gojira’s Amazonia, the double paddle especially has more punch
• The mids are slightly forward and doesn’t sound that recessed
• The treble sounds more open and the imaging and detail retrieval is just amazing, i can definitely hear the notes that i need to focus more previously in order to hear it, the K9 AKM does it with ease, Hans Zimmer’s Why So Serious ( The Dark Knight )
• Soundstage has more width and depth, doesn’t sound that 2D anymore

Spirit Torino Twin Pulse IEM

• The Twin Pulse is neutral with slight warmth on its own, based on my listening impression pairing it with K9 AKM, the soundstage is definitely “bigger” than before, imaging that is already good has been taken a step further with excellent separation as well as layering, simply amazing
• Bass is slightly faster, but the rendered texture is also improved
• Not much changes on the mids, perhaps the vocal positioning is slightly being pushed forward
• Imaging and separation is very good as you can clearly pinpoint the instruments easily

Sony MV1

• This particular pairing is the most interesting to my ears
• The MV1 itself is leaning towards neutral and slight warm, with a slight lift on the mid bass
• Listening to MV1 with the K9 AKM, bass has better control and tighter, while retaining the punch, i also noticed a slightly better sub bass extension
• Slightly better separation and imaging, in terms of detail retrieval, not much changes
• Soundstage has very good width and depth to it and seems to image better as well

Comparison (Earmen ST-AMP)

• Uses different DAC chip (ES 9280) and has lesser power output compared to K9 AKM
• The sound signature is leaning towards clean sounding and uncolored
• Feature wise, the ST-AMP is rather minimal and straightforward in terms of input and output, a 4.4 balanced and quarter inch headphone output, 4.4 balanced input and RCA input, whereas the K9 AKM sports a plethora of inputs and outputs, which i’m not gonna be mentioning as you can refer to the specs that i have posted above
• The ST-AMP to my ears sounds very natural and sometimes a little too plain if you’re craving for some coloration, bass is not being emphasised, the mid range is very natural, treble is smooth but retains enough energy, but ST-AMP’s star of the show lies within the amplification, i have tried using K9 AKM’s DAC line out to the ST-AMP and it brought out every bit of details that the AKM DAC’s capable of
• All in all, as a DAC/AMP, the ST-AMP does a good enough job, but K9 AKM does it a whole lot better as a DAC/AMP

Final Thoughts
Having tested and used the K9 AKM for several months prior to publishing this review, the K9 AKM definitely has what it takes to make a statement in the fast moving market with various competition. The K9 AKM is a very versatile product sporting various inputs and outputs. The K9 AKM’s sound will please most listeners out there who are looking for natural with a slight coloured sound.
The power output is definitely sufficient for most IEMs and headphones out there which are not power hungry. (Tested with the headphones which I owned, Hifiman Sundara Open Back, Hifiman Edition XS, Hifiman Sundara Closed Back, Aune AR5000, as well as Sony MV1). In terms of sound, it is definitely not neutral yet the coloration is somewhere in between and quite balanced overall. Fiio App compatibility is a welcoming feature as well, it allows you to set the filters as well as EQ/PEQ, and also the indicator light surrounding the volume knob.
All in all, the K9 AKM is a very capable dac/amp coupled with a good line out capability,hence the K9 AKM gets a recommendation from me.

*A big thanks to Fiio for sending this over for the purpose of this review. I thank them for their support.

Head over to their official AliExpress Store and official website if you are interested in getting one:

Fiio K9 AKM Product Page
Fiio K9 AKM Purchase Link - Non Affiliated

The K9 is FiiO's mid-range all-in-one desktop DAC and headphone amplifier. A model smartly positioned midway between the more expensive FiiO K9 PRO ESS and the less expensive FiiO K7. The FiiO K9 was originally released featuring dual ES9068AS DAC chips and THX AAA 788+ amplifiers. Variety is always welcomed so FiiO has decided to introduce a version with an AKM DAC chip thus the FiiO K9 AKM was born. The AKM version is $30 more expensive than the ESS.

Technical stuff

The only difference between the FiiO K9 AKM and the K9 is in the DAC chip which is an AK4191+AK4499EX combo by AKM instead of the dual ES9068AS by ESS. Everything else has remained the same. The balanced amplifier is still based on dual THX AAA 788+ modules that deliver the exact same power output as the original K9. Two OPA1612 handle the low-pass filtering, two OPA1602 act as the buffer and the NJU72315 is the volume IC.

The PCB of the K9 AKM features a partitioned layout, fully separating the major sections of the audio circuit - the power supply, signals, and analog signal loop. The linear power supply is based on a toroidal transformer paired with 4 massive 4700uF capacitors to provide clean continuous power. Furthermore the digital and analog portions of the K9 AKM receive power separately to reduce interference between the two audio circuits.

The FiiO K9 AKM has an XMOS XUF208 decoder with dual-clock management that supports up to 768kHz/32bit PCM and DSD512. Input sampling rate is displayed with the aid of a circular RGB light around the volume knob.

More technical information are available here.



Bluetooth connectivity

The K9 AKM employs the QCC5124 Bluetooth chip with support for LDAC/aptX HD/aptX Adaptive and other high-res Bluetooth codecs for wireless reception only. Bluetooth connectivity is stable and the audio quality is very competitive. Not the same as from the wired digital inputs but still good and very useful for situations when you can't use them.

FiiO Control application and EQ

The K9 AKM is compatible with the FiiO Control application which allows access to more functions. You can adjust various settings such as 6 types of digital filters, status indicators, EQ, and channel balance. There are 7 music tuning styles pre-set on the EQ of the K9 AKM while you can also self-define the PEQ and store your adjustments in one of the three available memories. Unfortunately the EQ is only effective in Bluetooth reception mode. The FiiO K9 AKM supports the low energy Bluetooth protocol so you can use the FiiO Control application even when the Bluetooth is switched off.



Non Audio stuff

The design of the AKM version is identical to that of the original model. The FiiO K9 AKM features an all aluminum, rectangularly shaped, chassis that is robust, very well made and finished with a smooth, black mate color. The size is compact enough to fit virtually anywhere and you also have the option to place the K9 AKM vertically with the aid of the included stand.

Digital inputs are the same with the K9 except the addition of a side mounted USB type-C port as it is also found in the FiiO K9 PRO ESS. A very useful addition that was missing from the FiiO K9. Other digital inputs include USB type-B, optical, coaxial and Bluetooth. The FiiO K9 AKM also has stereo RCA and balanced 4.4mm line inputs so you can connect analog sources and use it as a standalone headphone amplifier.

The selected inputs are displayed with the aid of the five LED lights that are positioned in the upper right corner. Two buttons and two switches are used for input selection, gain setting, output mode and power standby/mute.

The FiiO K9 AKM has three headphone outputs (6.35mm, 4.4mm and 4-pin XLR) positioned at the front, plus stereo RCA and balanced XLR line outputs at the back. The device supports three output modes: headphone out, pre-out and fixed level line out.

Accessories

The package includes a power cord, six adhesive feet, a spare fuse, the vertical stand, a USB data cable and a 3.5mm headphone adapter. Fitted at the device are rubber plugs for the USB type-C and 4-pin XLR inputs to protect them from dust when not in use.



Power output

The headphone amplifier of the FiiO K9 AKM is capable of delivering 2Wpc/32Ω or 780mWpc/300Ω from its balanced output and 1.5W/32Ω or 200mWpc/300Ω from the 6.35mm. Lots of power to run most headphones except some really difficult ones, like the HIFIMAN Susvara. The amplifier matches very well in terms of power with headphones like the FiiO FT5, the HIFIMAN Susvara or the Sennheiser HD660S2.

The headphone amplifier of the K9 AKM features three levels of gain (low, medium and high) for better adaptability to various loads. Background noise is inaudible even with very sensitive earphones such as the FiiO FX15.

As per usual practice the FiiO K9 AKM was left playing music for about 100 hours before listening evaluation. All cables used are of pure silver made by Lavricables

Audio stuff

This section includes comparison notes between the K9 AKM and the original K9.

The question to arise is, can a different DAC chip, when everything else has remained the same, make the AKM version sound radically different from the original? Well, the answer is yes and no, these two iterations of the K9 do sound different but they also share some common characteristics.

The FiiO K9 AKM has stellar sound quality, that admittedly surpasses the asking price, and offers great sonic performance that guarantees satisfaction no matter your music preferences or the headphones used. This is a neutral DAC/amp with excellent tonal balance, unquestionable transparency and mirror-like fidelity. The sound is crystal clear and well defined with very competitive technicalities and solid driving force.

The K9 AKM is capable of producing deep bass that is fast, tight and controlled with plenty of inner clarity and excellent layering. The K9 AKM is dynamic and impactful with full bodied and weighty textures. The THX amplifiers are slightly limiting the perceived spaciousness and the bass is not as resonating, the sound could be more atmospheric, but the AKM version fares much better in these departments than the K9. The latter might offer better clarity and overall technicalities, it is also more disciplined with a faster decay than the AKM but it also sounds a bit drier, leaner and not as full as the AKM.

The mid-range is open sounding, present and tonally balanced, crystal clear and well defined. The sound temperature is rather neutral, neither warm nor cold, but it slightly shifts warmer than the K9. The K9 AKM produces more colorful harmonies with better overtone diversity than the K9, the timbre is natural and more realistic, while the textures feel richer and rounder. The AKM DAC chip counterbalances the academic sterility of the THX modules and rearwards the listener with a bit more musical and engaging sound signature. Still the ESS version is the most technically adverse, resolves finer and has better mid-range clarity, transparency and articulation.



The most radical sound difference between the two is to be observed in the treble section where the AKM version sounds more lifelike and effortless, not that etched and with less digital glare. The treble of the AKM version is pretty extended and energetic, with plenty of airiness and shed light, but not as sparkling and luminous as in the K9. The latter is the more resolving one and delivers deeper detail extraction but it also sounds a little brighter and more academic. It is also faster and more vibrant compared to the more relaxed and blunt AKM. The overall feeling after side by side listening with the two units is that the K9 AKM is slightly more musical sounding than the K9 but not that transparent and clean.

A couple of differences also apply to the soundstage where both units do sound open and spacious with very satisfying extension and depth layering, especially from their balanced outputs. The AKM is a little more holographic, atmospheric and immersive but the ESS K9 has unmatched imaging precision and pinpoint positioning.

It should be noted though that the sound differences between the two devices are not in a night and day fashion. They do have their own unique and clearly distinguishable personalities but they also share a lot of common characteristics.

All-in-one

For this section I am literally copying myself from the original FiiO K9 review:

“The overall audio performance of the FiiO K9 AKM is of the same high quality both from the headphone and the line outputs thus making it an ideal option for use with headphones and powered monitors alike or even as a standalone DAC. Furthermore, the headphone amplifier of the K9 AKM is very transparent and will mirror the sound characteristics of an external analog source without any further coloration. It gets perfectly clear that the FiiO K9 AKM is a high quality desktop audio source that can meet various usage scenarios.

Comparison with the FiiO K7

The FiiO K7 BT is another option for anyone looking for a more compact and budget friendly desktop DAC/amp with truly balanced circuitry and AKM DAC chips. It features two AK4493SEQ DAC chips and dual THX AAA 788+ amplifier modules that are capable of 2Wpc/32Ω from the balanced output. This is the exact same power output as the FiiO K9 but the devil hides behind the lines because the later has a more robust, internal power supply that helps it to deliver 780mWpc/300Ω than the 560mW of the K7, thus making it more capable of driving high impedance headphones. Another notable difference is the lack of a balanced XLR output and a 4.4mm line input.

When it comes to sound quality, the K9 AKM is the better sounding of the two. If you have the space and the budget to afford the K9 AKM then you are buying an audio device that is more dynamic and impactful with
blacker background, it has better transparency and clarity, as long as it sounds finer and more resolving. Additionally the sound is more fluid and effortless, the treble is smoother and less sterile, with less digital glare while the overall timbre is more natural and realistic.

Conclusion

Exactly as the original FiiO K9, the AKM version offers a near flagship level of audio quality with plenty of connectivity options at a price so low that is hard to beat. Furthermore it differs from the original version by sounding a little smoother, slightly warmer, more natural and less academic without sacrificing too much in transparency and technicalities. Variety is always welcomed, two is better than one and the user now has the option to choose between two flavors of the same awarded dish that are equally delicious. Whether you pick the plain K9 or the AKM version, rest assured that you are buying an excellent sounding all-in-one desktop DAC/amp with an amazing price to performance ratio.

The review sample was kindly provided free of charge.

The price of the FiiO K9 AKM is $530 and you can buy it from here.

FIIO K9 AKM
AK4191EQ + AK4499EX + THX AAA 788+ Amplifier
$500~

First, let me thank FIIO for sending me this DAC in for review, rest assured my review is 100% my own personal opinion.
If you're interested on the K9 AKM, you can check the official FIIO page below
https://www.fiio.com/K9AKM

Unboxing
Inside the box, you get :

• K9 AKM
• Quick start guide & warranty card & big warning card
• Power cable
• Vertical stand
• USB Cable
• Spare fuse
• 6.3mm adapter
• Rubber port cover
• Rubber feet

Build Quality

Is top notch, it has full metal and really solid feel to it.
Top of the K9 AKM, it has Hi-Res and THX logo

Front of the device it has XLR4, 6.3mm, 4.4mm port, volume knob that feels satisfying to turn, output switch, gain switch, input button and multifunction button.

Right side of the device, it has a type C usb in, the first physical difference vs K9 OG.

Below the device, there is a switch for voltage region

While the backside of the device has power switch, power port, bluetooth antenna, usb in, optical in, coax in, 4.4mm bal in, line in, pre/lo and bal out, super complete ports from FIIO for every need.

When you connect the K9 AKM to bluetooth, you can set :

• UAC Mode
• Status Indicator / LED
• Bluetooth Codec
• Input Source
• EQ
• Low Pass Filter
• Channel Balance

via FIIO Control APP
Sound

I would like to describe the K9 AKM as a warm-ish, analogue, and open sounding at the same time.

The K9 AKM has 6 filters that you can choose, but i found the default “Sharp Roll-Off Filter” to be my favorite.
So for the sound part I will describe it with the default filter.

Bass on the K9 AKM is somewhat highlighted or you could say it a bit accented in a way. It is flat but has a very satisfying maximum depth and nice mid-bass punch accent, not only that, the bass control tested using FIIO FT3 350ohm, is simply amazing.

Layers of the bass is also very good, it just like if you want a Hi-Res bass, this is the combination pair you want to get for sure.

Midrange on the K9 AKM is very natural and organic, it is a bit on the warmer side, not much, but its a tad warm for sure.
Vocal sounds hyper realistic and instruments has a very good organic decay to it, especially tested on song that has violin or guitar on it.

Such as Violet Evergarden OST, Mei Ehara Ampersands Album.

Midrange presentation here is almost like its portable brother the Q15, very liquidy and effortless but with the K9 AKM, it has more warmth and even more organic sound.
It does not demand your attention but its definitely has a charm that you want to keep listening to it, it is hard to describe but its there.

Treble here is smooth but very detailed, extended and open sounding, it has that analogue characteristic for sure, but it sounds more open compared to the Q15.

Just like the Q15, I've tested the treble using my Hidizs MS5, the “ZINK” of the MS5 is gone but it sounds more open and resolving compared to the Q15 (with wrong source, the MS5 could sound really piercing).

Treble here I'd dare say has a complete layering and is very, very, very good for its price of $500.
Compared to the Q15, the K9 AKM has even more extra layers to the treble, probably thanks to its superior power supply and its THX AAA 788+ amplifier.

Treble presentation is also presented just like the Q15 with its same AK4191EQ + AK4499EX chip configuration, it has that effortless liquidy presentation, the details are pushed a little bit forward compared to the Q15 but it is really enjoyable to listen to, especially if you're a detail junkies.

Overall sound presentation here if I had to compare it to the Q15 is that both has a very analogue characteristic sound to it, but the K9 AKM takes it one or two steps further to enhance what is already mindblowingly great sound of the Q15, such as the added warmth and more open and complete layer of the treble.

Once again, the AK4191EQ + AK4499EX DAC managed to make me impressed.
This DAC has a resistor ladder characteristic sound with the technicalities of a DS DAC.
With the K9 AKM, you get best of both world for sure just like on the Q15, but probably thanks to the superior power supply and THX AAA amplifier, it improves it to be even more enjoyable DAC-AMP to listen to.

Technicalities

Is mindblowingly good for its asking price of around $500USD
Myself probably going to repeat what I said on the Q15 review with the K9 AKM because it is just like the Q15 on steroid, but it is really, really great.

Stage is really grand and open with hyper realistic stage layering.

Detail Retrieval is spectacular ! It does not simplified anything at all, and has complete layers of microdetail, the layer is also very organic and on the “wet” side

Imaging is excellent, any IEM I plug to the K9 AKM pretty much sounds holographical. One tips from me if you want to know how good your DAC– AMP imaging capabilities :
Try use your cheapest cans available at hand, if it can make your cheapest cans sounds holographic, then there you have it, great DAC-AMP imaging performance.

Separation & Positioning is very good, different from the Q15, sound presentation here is a bit pushed forward while still managed to sound smooth, effortless and liquidy, you can easily pinpoint which sound is playing and where its position very easily, even when you're multi tasking (like when I'm writing this review)

Output Power is very powerful, It is rated at 780mW at 300ohm, 2000mW at 32ohm on its balanced port, but rest assured, Noise Performance on this DAC-AMP combo is also very good.
It is dead silent black background on my hyper sensitive Hidizs MS5.

Bluetooth vs USB
I do notice a bit of depth loss with the bluetooth, so if you want maximum performance of your K9 AKM, try use the USB Input if possible.

SE vs Balanced
Obviously with balanced you get more power, tonality wise it sounds similar, but on the balanced port, at least to my ears, you can get extra micro spacing on the sound.

Comparation

FIIO Q15
The Q15 has same DAC chip configuration. It also has the same analogue characteristic to it just like the K9 AKM.
The main difference between Q15 and K9 AKM is obviously, with the Q15 you can use it as a portable / transportable DAC-AMP, while the K9 AKM is solely dedicated desktop DAC-AMP.

Sound wise, it is pretty similar, but the K9 AKM has more warmth but open sounding on the treble region.

Performance wise, the K9 AKM is just like Q15 on steroid, everything I said on the Q15 review is like taken one or two steps further enhancement from FIIO, crazy good stuff.

If you don't need a portable DAC-AMP or you feel the Q15 is too big for portable use, then why not take the K9 AKM instead, the $100 price difference in my opinion is justified for what you get in return.

FIIO K7
Cheaper alternative to the K9 AKM, if you really want my honest opinion, the K7 sound performance is far more simplified and not as good compared to the K9 AKM (expected because of different price point) though if you consider pricing of the K7, then K7 is still a very good option for its price, but the K9 AKM is just like a league ahead of the K7.

If you have a limited budget then sure, the K7 might works for you.

FIIO K9 OG
The older brother of K9 AKM, I only tested it on demo so take this comparation lightly.
The K9 OG to my ears sounds more like your traditional DS DAC, it sounds more “precise” rather than “analogue”.
Tonality and timbre wise, I do prefer the AKM version because it has a very natural analogue sound to it.
Technicality wise, it is on par with the K9 AKM.

In my opinion the K9 AKM is definitely an improvement compared to the K9 OG, because it has superior tonality and timbre, well... at least to me personally.

Though if you already have the K9 OG, I would hold up before buying the K9 AKM, because the difference is more on the tonality side, its just like same main product with different flavors.

Conclusion

The K9 AKM is a really joyful desktop DAC-AMP combo device to listen to and I can whole heartedly recommend the K9 AKM for its asking price of $500USD.

If you're in a search for a $500 USD DAC-AMP combo and don't have a K9 yet, then personally myself would recommend you to get the newer AKM version because it has that analogue characteristic sound to it.

Thanks to the K9 AKM, my days has been more joyful lately, It is really a device that has its own unique charm that make you want to listen more and more and re-discover your library.


Thanks for reading this far.


Just in case you're Indonesian or understand Bahasa Indonesia, you can watch review of the K9 AKM here


-littlenezt.