FiiO K9 Pro ESS – The All in One Solution

Introduction

Fiio just never stops. They just want to cover every price bracket with their relentless innovative yet creative audiophile products one after another. Herein, AudioMonsta was very lucky to be able to test their latest flagship all-in-one desktop DAC AMP, the Fiio K9 Pro ESS. Last year Fiio released the earlier unit of K9 Pro with AKM AK4499EQ DAC version however, the chip shortage situation currently being hit by AKM due to the fire incident had change the decision of the company to introduce the new K9 Pro with not one but, two chips of ESS ES9038Pro DAC are being used in a one desktop unit instead. Coupled with various other cutting-edge internals and the latest dual THX AAA 788+ amplification units, we finally have the verdict of the K9 Pro ESS. Enjoy the reading folks.

Packaging & Accessories

The K9 comes with a big and heavy box package. Inside you will be greeted with a massive voltage input requirement warning where in certain region you may need to adjust the voltage input at the bottom of the device. In our case, we opt for the 230 V. Furthermore, the box also contains pretty much complete accessories such as power cable, USB cable, Bluetooth antenna, backup fuse, extra sticker labels, 3.5 mm to 6.35 mm adapter, custom stand for vertical mounting, manual, and documentations.  

Design

Without a doubt, K9 has a ton of useful features but before I jump into that, let’s talk about the design first. I like the design a lot. Despite the typical box shaped body, the slight etched design on the top part gives a character and elegancy towards this flagship DAC AMP. Moreover, the all black and gold colour combo is gorgeous to look at and the aluminium alloy chassis is solidly built and feels heavy (~2.7 kg) because of the internals components, circuits, and power supply consisted inside of it. The gold-coloured volume knob is positioned right at the centre and the base ring is attached with an LED for sample rate, Bluetooth codec, and abnormality alarm (see Fiio FAQ) indicator. The rotation is also smooth and very well controlled for every level of gain. Not only that, the K9 can also be mounted vertically by using the custom stand supplied in the box which can be useful if you have a tight space at your place setup. If there’s one thing that I don’t like about the design is probably the matte-like finish of the metal body which is unfortunately a finger stain magnet. In terms of internals and specifications, I won’t go into details since all the information can already be found on their product page. There is something that’s worth to be mentioned especially if you’re Tidal user in which the K9 is also equipped with an MQA renderer up to 8x unfolding. But despite the top of the line labeled desktop DAC AMP by Fiio, interestingly the K9 is only able to support audio format up to 32 bit/384 kHz and DSD 256, this is due to noise issue when going above that sample rate as answered by Fiio in the FAQ section. Nevertheless, one can also look at the summary list in the parameters section below.

Features

The K9 also has plenty of features when it comes to inputs, outputs, and functionality support. On the front, there are three outputs; 6.35 mm single-ended, 4.4 mm balanced and 4-pin XLR balanced outputs. There are also switches for different output such as DAC, Preamp, and headphone; three gain settings of low, medium, and high for every kind of IEM and headphone. Other than that, input button is used for setting the digital input desired in example. Bluetooth, USB, coaxial, optical, or line in. There is also a sleep or mute button, where pressing the button will mute the volume while holding the button will make the DAC go into sleep mode. There is one thing to criticize here though, which is the grey colour of the labelling which is very hard to see or read most of the times. Maybe a white colour or larger font should do the job better. At the back, there’s power switch and an AC input for their integrated linear power supply which is a great addition for cleaner power cycle. Then, there are digital inputs mentioned earlier and also analog section such as RCA for line in/out and balanced out. Surprisingly, there is also a 4.4 mm line input (hello iFi). Last but not least, there is a lonely USB Type-C digital port located at the side of the K9 chassis for connecting the K9 with your smartphone or DAP.

Fiio Control App

Via Bluetooth Low Energy (BLE) connection, the K9 can be connected with Fiio Control app on Android and iOS devices. This app added some extra functionality to easily control the K9 wirelessly. For example, there is a status indicator pattern function so you can adjust the colour into three options into OFF, Default, and Multicolor gradient. There is also brightness level setting for that LED indicator. Furthermore, there are also different Bluetooth codecs that can be picked and enabled for the K9 such as aptX-adaptive, AAC, LDAC, aptX, aptX-LL, and aptx-HD. Another useful function is the select input source (USB, OPT, COAX, LINE, BT) for a wireless digital input switch. Apart from indicating sample rate and digital input mode being used, the app also has a built-in 10-band equalization (EQ) settings and presets, though it only works for Bluetooth input. There are also various DAC filters and channel balance setting exclusively for the Bluetooth input. Regarding the DAC filters, I couldn’t differentiate any sound differences between all 7 filters option.    

Parameters:

Retail Price & Where to Get

This review unit was sent by RED APE Headphone Store and Fiio. Massive thank to both of them for giving us the chance to review this product as honest as possible. The K9 Pro ESS is exclusively available for RM 2999 on various RED APE store platforms such as Shopee, Lazada, and their own website. Do contact them for stock availability. For global customer, check out the AliExpress store.

Purchase Link :  

FiiO K9 Pro Flagship Desktop and Amplifier | Shopee Malaysia

FiiO K9 Pro Flagship Desktop DAC and Amplifier | Lazada

Red Ape Trading – Red Ape Headphone Store

FiiO K9 Pro AKM/ESS Desktop Headphone Amplifier Bluetooth AMP USB DAC DSD Decoder AK4499/ES9038PRO*2 chip| | – AliExpress

Test Tracks

Tonality

When it comes to subjective tonal balance, the K9 Pro ESS is simply a smooth sounding DAC AMP without accentuating too much towards their classic almost dry-ish/sterile Fiio sound signature. The sound signature coming from this DAC AMP is probably the result of balance combination between the highly detailed audio reproduction from the dual ES9038Pro DAC chips and the extra finesse sound from the dual THX 788+ amplification. While maintaining a neutral sound response, the K9 is able to deliver a powerful dynamic impact and swing into your headphone.  

Bass

The K9 has a powerful bass response, not really in terms of quantity or volume where it mainly remains linear and deeply extended (maybe with the exception of slight boosting in the upper-bass region), but rather with regards to quality or physicality. The impact or slam delivery is just powerful and full of macro textures and micro nuances, depending on the actual recording of the record. Not to mention the attack part of the transient and overall control in this low-end region which are also brilliant. However, one must be careful especially with dynamic drivers because they may get overpowered and become too bassy at certain times, reducing the degree of separation between the bass and midrange regions. With the K9, I would say that finding a good synergy with the right cans is still a must which may or may not be a good thing.    

Midrange

Based on my experience and observation, Fiio midrange tends to have somewhat “tasteless” or sterile sound. There’s always a lack of character in the vocals and general experience. Now, the K9 in my opinion still follows that trend although not too much, fortunately. While the mids are not forward and bodied enough to extract every micro detail of vocal textures and some of the instrument notes such as in piano or guitar, the midrange is not recessed by any means. It’s just neutral which is perfect for neutral head. Nonetheless, what is sure is that the mids still have plenty of details and respectable authenticity in the timbre. Vocal presentation is again neither recessed nor forward, just neutral. Any veil or harshness occurrences will most likely be caused by the cans itself.

Treble

One of the surprises offered by the K9 is in the treble region. The treble is very smooth as if it was reduced by just one level to make that typical ESS glares easily go away. No sibilance and sharp peaks were catalyzed by the K9 unless they are produced by the cans or track themselves. That being said, it is important to note that some people may found the treble to be less extended in relation to that final “extra air”. This is where synergy pairing comes to play an important role so that you still get the sound and tone that you desire. Fortunately, pairing the K9 with some aggressive sounding cans can be a perk since it smoothens things a little bit in the treble area.      

Soundstage & Imaging

Fiio stated on their website (see FAQ) that the K9 has a regular size soundstage in which I tend to agree with it. It wasn’t amazing to the point like it was artificially enhanced nor it was disappointingly small or compressed neither, at least to my ears. Rather than IEM, headphone or speaker is likely to be the best pairing with the K9 for those who prioritize soundstage performance. Internal soundstage or space within the staging is magnificent though. All instruments are able to breath and separate themselves from each other contributing to an excellent layering capability. Imaging wise, I would say you will unlikely experience a full three-dimensional staging and imaging even so, the imaging movement and placing are just slightly short to be at supreme level.         

Separation & Timbre   

K9 is simply a highly resolving DAC AMP considering it price point. Any IEMs or headphones will be pushed to their limits to expose every detail and nuance in the recording. The sense of black background without any noise intrusion really helps the dynamic range and complex instrument layering to shine. Perhaps if I were to be really critical with this desktop beast, treble detail is the only weakness here in which more air presence and clarity up top would really help the K9 macro/micro-contrast to be even stronger. On the other hand, the decay part of the transient is quite good creating a somewhat natural timbre to be enjoyed with, though I wouldn’t call it the most natural or true to life experience, since that midrange character that I mentioned earlier is still influencing it.

Synergy

When it comes to DACs and AMPs, pairing synergy is always the main focus. This is also true with the K9 which I found that it pairs well with neutral or bright sounding cans such as the Hifiman HE560, rather than warm sounding headphone. The 2.1 W at 32 Ω output kept in the K9 arsenal is a perfect pair for the HE560 stubborn planar magnetic driver. The neutral-bright sound coming from the HE560 was safely balanced and further controlled by the smooth nature of the K9. The almost flat bass response produced by the planar was further energized with extremely nimble bass impact and tactility while simultaneously rendering a deep subbass extension in the background. The treble also remains extended and crispy while sibilance and peaks were reduced. Along with improved dynamic and technicalities, it is definitely a great sound.

Neutral/ bright IEM and earbud such as the Tanchjim Oxygen, Sonic Memory SM2, and Ksearphone LBBS were also great with the K9. The degree of separation and resolution were just further enhanced. V-shaped sounding cans such as CCA CRA and KZ EDX Pro were also great in terms of technical performance, however their bass quantities were a little bit too much for my taste. In contrast, custom-made earbuds such as Blur 256 PK32 and Imperial Audio Titan-22 which have warmish sound to them unfortunately didn’t have a good match with the K9. To my ears, this is due to them get overpowered and hence, resulting in a congested sound. What is certain though, the advantage of using the K9 is the low level of distortion and high dynamic range possessed by it, in consequence allowing maximum headroom for your headphone and IEM especially the hard to drive one.

Noise

With a desktop level and maximum power output of 2.1 W @ 32 Ω, it interesting to see how the noise performance of the K9. I tested every level of gain setting, and I can assure that there isn’t any noise even with high sensitivity IEM such as KZ EDX Pro. The dual THX AAA 788+ offers extremely low level of measurement and hence producing a dead silent and black background with all cans that I plugged in with. Even the sound from the Bluetooth (LDAC) is excellent, nearing the quality of using the USB input. This is again probably because of the low noise floor performance produced by the K9. Besides, output impedance stated is < 1 Ω for both types of headphone outputs so, this reflects a good unaltered sound signature coming from my tested earphones and headphones.    

Conclusion

All in all, the Fiio K9 Pro ESS is indeed a flagship level all in one desktop DAC AMP. It offers numerous features and functionalities for every type of audio needs ranging from earbuds to speakers and IEMs to headphones. The sound quality in my opinion matches up its price point and might even exceed some of the even higher priced DAC AMP solely based on other reviews and discussion in the community. Sure, there are some flaws and complaints with the design and sound performance, but nothing is really perfect even more so with it actually being affordable in comparison to some other top of the line desktop DAC AMPs out there. On top of all its glory with the measurements and actual sound quality, the design and ergonomics are also great at least to my eyes and experiences. Therefore, this product deserved to get our strong recommendation for a good value desktop DAC AMP that can do it all.

I would rate this product a solid 4.5 over 5 stars