Fosi Audio K7 Gaming HiFi DAC Headphone Amp

Fosi Audio K7 Gamers DAC and Headphone amp​

In the ever-expanding universe of hi-fi audio, the pursuit of exceptional sound quality often leads enthusiasts down paths filled with complexity, high costs, and intimidating setups. However, every so often, a brand emerges that manages to defy these expectations by making high-quality audio remarkably accessible.

Enter Fosi Audio, a company dedicated to providing audiophiles, music lovers, and newcomers alike with powerful yet compact amplifiers, DACs, and audio solutions that promise outstanding performance without breaking the bank.

Fosi Audio has swiftly garnered attention for its ability to combine sleek, minimalist designs with robust engineering, offering products that easily integrate into both seasoned audiophile setups and beginner-friendly environments. Whether you’re looking to elevate your desktop listening experience or enhance your home stereo system, Fosi Audio positions itself as a game-changer, challenging traditional perceptions about the cost and complexity required for exceptional sound.

In this review I will have a look at the new Fosi Audio K7

The Fosi Audio K7 is positioned as a “gaming headphone amp & DAC,” targeting audiophiles and serious gamers who value high-quality audio. Specifically for gamers, the K7 includes a microphone input with built-in noise cancellation, ideal for clear communication during online gaming sessions.

The K7 stands out as an appealing device because it combines a high-quality headphone amplifier and DAC with excellent operational features, and there is even a very nice informative LCD screen

The K7 offers four digital inputs:
– Coaxial
– Optical
– Bluetooth
– USB-C (The K7 supports UAC 1.0 and high-resolution UAC 2.0 audio)



Outputs:
– RCA Analogue, to connect to an external amp or active speakers.



The unit includes volume control, adjustable treble and bass controls (which can be bypassed)

Two headphone output, single ended 3.5 mm and a balanced 4.4 mm jack. By pressing the left volume knob you can switch between low and high gain. And left from the headphone ports a microphone input.

From a technical standpoint, the DAC is equipped with the AKM4493SEQ chip, known for handling PCM audio signals up to 384kHz/32bit and DSD256 via USB, while coaxial and optical inputs support resolutions up to 24bit/192kHz.

Bluetooth connectivity is managed by the Qualcomm QCC3031 chip, which provides lossless audio streaming at 24bit/48kHz and supports aptX HD, aptX LL, aptX, AAC, and SBC codecs.

The amplifier circuit employs dual chips OPA1612 and TPA6120 enabling effective driving of headphones with impedance ratings from 16Ω up to 300Ω.

The unbalanced 3.5mm headphone output delivers 600mW+600mW at 32Ω (with THD+N <1%), the balanced 4.4mm output increases this significantly to 2100mW+2100mW at the same impedance and distortion rating.

The unit is powered via an external power supply rated at 12V 2A


My test equipment:
– Fir Audio M5
– Arya Stealth
– Eversolo DMP-A8
– MacBook Pro 2024
– Playstation 5

Tested Albums:
– Stacey Kent – Summer me, Winter me
– Robin Mckelle – Alterations
– Terell Stafford – Brotherlee love
– Catherine Russel – Strictly Romancing
– Chris Minh Doky/Larry Goldings – Scenes from a Dream

Sound Quality​

The sonic presentation of the K7 is impressively transparent and balanced, faithfully reproducing the entire audible spectrum without coloration. It offers genuine neutrality, conveying exactly what’s present in the source material. Across various scenarios, music playback, gaming sessions, or teams meetings, the audio remains effortlessly smooth and articulate. Enough power for planar headphones yet sensitive IEM’s exhibit no audible noise, hiss, or distortion, resulting in an exceptionally pure listening experience.

Treble​

High-frequency performance on the K7 is articulate and refined, revealing fine detail and excellent definition. The integrated tone controls offer adjustments smoothly. Treble changes are subtle yet effective. This design makes it straightforward to enhance brightness or tame overly sharp recordings gently. Gamers, particularly those requiring precise micro details, will find these detailed adjustments beneficial.

Bass​

Bass reproduction on the K7 is tight and dynamic, delivering fast performance without overwhelming the listener. It has depth and punch, enriching music and enhancing immersion in games. Adjustments are here just as gradual, meaning you won’t experience abrupt tonal changes. This thoughtful implementation allows users to finely calibrate warmth and impact without any loss in clarity.

Bluetooth​

The pairing process is fast and effortless, and once connected, the device maintains a stable, uninterrupted signal, even a few meters away from the device. Audio quality via Bluetooth is impressively clear. It is no secret I am not a fan of bluetooth audio, but this exceeded my expectations. It is a shame LDAC is not supported though.

Conclusion​

The synergy between the AK4493S DAC chip and the TPA6120/OPA1612 amplifier is impressive. Immediately noticeable was the spatial precision compared to similar units I’ve heared before, especially in this price range!

The overall sound signature strikes a compelling balance, revealing but not too analytical, enriched with a pleasing touch of warmth. Its remarkable coherence ensures a pleasant listening experience, and should you prefer a different sonic flavor, subtle tone adjustments provide ample flexibility. I liked the bypass mode the most though, altough the difference between bypass mode was almost none existent (which is a

Last but not least, the device also fits perfectly in my day to day use, in my working day at home with a lot of teams meetings, muting was faster than a mouse click.

You can read the reviews and more at my website as well:
https://jjazzifi.com/fosi-audio-k7-gamers-dac-and-headphone-amp/

Quick disclaimer: I’m not really a technical guy when it comes to these DACs/AMPs since each one of them has their own unique build and chipsets which I am new to and don’t know much about. I am also a casual gamer because as a working adult with responsibilities, the saying goes “the moment we sit on our chairs, we fall asleep right away” but after extensive use of the Fosi Audio K7, I can confidently say that this DAC/AMP really lives up to the reason why it was made in the first place which is gaming.

And as always, all these thoughts and opinions are mine, I did not read or watch any reviews prior to making this one and my only source of technical and specification information is from Fosi Audio’s website(fosiaudio.com/pages/fosi-audio-k7-dac-amp) and their Kickstarter page(https://www.kickstarter.com/projects/fosiaudio/fosi-audio-k7-gaming-headphone-amp-dac).

The following IEMs are used to test the Fosi Audio K7:

• Orveti Dynabird
• Hiby x Faudio Project Ace
• DUNU x Gizaudio Davinci
• LETSHUOER Cadenza 12

I already posted my review of the Dynabird and will be publishing my reviews for the other three IEMs in the next few weeks so stay tuned for those!

Thank you so much to Ryan Fosi and Fosi Audio for sending the K7 to our local community for a review tour! Each one of us really loves it and how much it brings to the table especially for us who want to have an edge in competitive gaming while also enjoying audio. We hope to have more review tours with you in the near future!

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So let’s begin.


This is my first review with Fosi Audio as a brand and when they told us that they have a Kickstarter for the K7 which is a gaming desktop DAC/AMP we all got excited. At the time of writing this review, the K7 is still on Kickstarter but a demo unit was shipped to us for a local tour review although the price range is 179$ for those who are curious. When checking both their website and Kickstarter page, there’s a lot of technical information listed but here is what I gathered:

• 2.1w + 2.1w High Power Output
• 0.0002% Ultra-Low Distortion
• PCM 384kHz, DSD256
• Flagship Chipset Integrated (AKM AK4493SEQ, XMOS XU208, Qualcomm QCC3031, Texas Instruments TPA6120 & OPA 1612)

Other than those chipsets stated in both their website and Kickstarter page, they also included some functionalities such as a 1.5-Inch LCD Display, 5 buttons, dual control knobs for different purposes, comprehensive connectivity and a lossless Bluetooth low-latency transmission. So it is great to hear that Fosi Audio did a lot of research and development to create the K7 because it not only looks sleek but it is able to accommodate different types of connectivity on both input and output sources.

The K7 is advertised as both a gaming and music DAC/AMP which is unique since a lot of people who make reviews say that this device is perfect for gaming but surely the companies/manufacturers did not have that in mind. Sure, you can use those devices for gaming but the reason why it was built was not purely for gaming but for day-to-day usage; that’s when Fosi Audio decided to step up and say “Yeah, we are definitely creating the K7 not only for music but also for gaming”. It’s nice to see that companies/manufacturers are now considering that since hardcore gamers are willing to spend a bit more money if it gives them a slight advantage over their opponents.


Moving onto the K7, in the front face we have three main inputs; starting from the left is a 3.5mm microphone input which has an intelligent noise reduction for clearer communications, the middle which is another 3.5mm input but this is for a single-ended headphone output which has a rated power ≥600mW+600mW @32Ω and lastly a 4.4mm input for a balanced headphone output with a rated power ≥2.1W+2.1W @32Ω. The back of the K7 has the following:

• RCA Output
• Bluetooth Input
• Coaxial Input
• Optical Input
• USB-C Input
• DC 12V Power Input

What’s also unique about the K7 is that it has Bluetooth Capability which is quite rare considering that many will agree that wireless connectivity is not the best and would rather stick to wired. These are the specifications of the Bluetooth:

Hi-Res Bluetooth Codecs

• Equipped with the Qualcomm QCC3031 Bluetooth chip, supporting aptX HD, aptX LL, aptX, AAC, and SBC codecs.
• Under 40 msImperceptible latency
• Lossless PCM 24bit/48kHz Sampling Rate

And to top it all off, the build quality of the K7 is very solid but surprisingly lightweight, while the weight is still a bit heavy, for the size it makes perfect sense. It is way lighter than the FX Audio R07 Plus but heavier than the NEOHIPO DC10. The body is made from an all-aluminum alloy body with CNC integrated design. The top face has the LED screen, 2 knobs and 5 buttons. I will not get into technical details on how to use each one of them as this will feel like a tutorial rather than a review.

I really like the build quality of the K7, it is both durable and lightweight while still offering top notch sound quality and for the price point of 179$, the amount of technical capabilities the K7 can accommodate makes it super worth it for the price.

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Finally we move on to the listening and gaming experience.

When using the K7, the overall sound quality that it provides to all the IEMs I used for testing is that it has a balanced tuning, it does not give a bright/shouty treble which causes a lot of sharp sibilance while also not giving any sort of muddiness. Bass response is smooth and pleasant, it will not shake your eardrums while still giving that satisfying punch that everyone loves. But the real star of the show is the sound staging and imaging.

Since the K7 was built to be used for both music and gaming, I find that it truly shines for gaming especially for those competitive titles like Valorant, Overwatch, CSGO and others that utilize sound and placement as part of having a strategic advantage. Being able to hear and know exactly where sounds are being played gives a huge advantage to the player and can even catch the opponents off guard. While this sounds like a cheating device, it is also used for music which offers insane amounts of imaging and a very wide soundstage but despite all that, if the player still did not improve on their skills while using the K7 then maybe it’s something called a “skill issue”.

I used the K7 while playing Honkai Star Rail and Fortnite and I must say that it brings out so much detail to the sound effects. Honkai is not really a competitive FPS game but rather it is a turn based gacha game, using the K7 obviously did not give me any advantage since it is a casual game but it made me appreciate the sound design of the skills and ultimate used by characters more but moving onto Fortnite, I will say that it did give me a competitive advantage against my opponents as I was able to tell where and how close they were to me and my squad despite having voice comms and music playing in the background. I am not a pro at this game by any means but I’m not terrible at it, but Fortnite has the option of disabling sound indicators so I did that to test the K7 as well as my skills and I did not have any trouble identifying which sound is being played and where.

One thing I would like to mention is that I have been using the K7 at 28% volume to give me accurate readings while gaming but also enjoying the sounds of music. It will take a little bit of finessing to get the right amount of volume but if you found it then you’re more or less going to stay at that level and not adjust it for a long time. Though this made me extremely curious how it would hold up if it were to be using in a sim racing gaming where immersion both feel and hearing are crucial to getting the fastest lap times and understanding the condition of your car; unfortunately I was not able to test this as I do not have any racing sim gear nor have any game to test it so maybe in the near future.

So, how about the IEMs that I used while using the K7? Were there any improvements to each and one of them when using it with a different DAC/AMP? The obvious answer is yes. The sound staging and imaging were bumped to 101% and since the IEMs that I used already have great sound staging and imaging, the K7 wanted to make use of what is available and add its own razzle dazzle. It is capable of powering anything that is thrown at it and you definitely won’t be disappointed. And since the K7 offers the option to boost both the Treble and Bass, going all the way to the max percentage of this volume yielded interesting results. Having the Treble maxed out did not give any sharp sibilance or distortions to the sound quality which caught me off guard while maxing the bass did not give any hurtful punch texture and rumbling to the ears. I like to think that these boosts are a bit subtle as every level increase did not have any major jumps but tiny improvements.

Overall, I highly recommend everyone to get the K7 both for audio and gaming because of the insane sound staging and imaging that it gives while also letting anyone with as much versatility with different devices experience the best sound quality that money can buy. It is a bit unfortunate that I was not able to test the microphone and Bluetooth features as my microphone has a micro USB plug and that I do not have any Bluetooth speakers lying around but surely someone else out there has made a review about those. For the price point of 179$, this is a must have and even if you’re not a gamer, the fact that it comes built if ever you decide to try it out is definitely a steal, talk about inclusivity. I’ve also attached pictures of what the K7’s LED screen shows with different options for you to check out.

Blup blup 𓆟 and happy listening!

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LED Screen Image Gallery:

MatAudiophiles

When music flows in your veins, choose a good guide!

Fosi Audio K7​

Fosi Audio K7

INSTAGRAM: LINK

YouTube: LINK


Prelude:
Fosi audio has been working on their new unique project for many months, built based on suggestions from fans. It is the K7 model. A device that is so unusual and extraordinary, because it combines the world of gamers and music lovers. In this review I will try to answer the question of whether it plays and, above all, who it will play. We do not know the official price of the product, but we can assume that it will be below 200 USD and above 150 USD. So it is a very reasonable and user-friendly budget. Fosi Audio is famous for its bold projects and very bold approach to audio. They also do not accept compromises, it has to be good and that’s it, if it is bad, they quickly learn from their mistakes. That is why I respect this company and its approach to audio.





Unboxing:
This time we receive the Fosi Audio K7 in a larger black box, similar to the one in which the great ZD3 DAC is packed, which I had the opportunity to review some time ago. Inside we find the manual, Bluetooth antenna, 12V/2A power supply and a cable for connecting the microphone, and a USB A/C cable with an adapter for USB C. This is a complete set and offers everything you need to enjoy the K7. The device itself has a bold style. It consists of an irregular shape and a fully metal housing. On the front panel we find a 3.5mm, 4.4mm jack and a 3.5mm microphone socket. Unfortunately, I missed the 6.5mm socket. On the back of the device we have a Bluetooth antenna, a power socket, a coaxial input, an optical input and an RCA line output with volume control. At the very top we find an OLED screen, a volume control knob, which is also a function button, and a second function knob. Additionally, we find five buttons to control the device’s functions.

Specification:


– AKM AK4493S DAC:
– XMOS XU208 USB Controller:
– OPA1612 Op-Amp:
– TPA6120 Headphone Amplifier: .
-Qualcomm QCC3031 Bluetooth Chip

4.4mm Balanced Headphone Output:
– Rated Power Output: L+R ≥ 2100mW + 2100mW (32Ω/THD+N<1%)
– SNR: 121dB
– THD+N: 0.0002%
– Dynamic Range: 121dB
– Noise Floor: ≤ 6.5μV
– Frequency Response: 20Hz-20kHz (±0.2dB)

3.5mm Single-Ended Headphone Output:
– Rated Power Output: L+R ≥ 600mW + 600mW (32Ω/THD+N<1%)
– SNR: 122dB
– THD+N: 0.0005%
– Dynamic Range: 121dB
– Noise Floor: ≤ 2.5μV
– Frequency Response: 20Hz-20kHz (±0.2dB)

RCA Output:
– Output Level: ≥ 2Vrms
– SNR: 121dB
– THD+N: 0.0005%
– Dynamic Range: 121dB
– Noise Floor: ≤ 3μV
– Frequency Response: 20Hz-20kHz (±0.2dB)

We have quite a few functions, in addition to adjusting the gain level, we can adjust the EQ, or turn it off completely, we can turn on the line or headphone output, additionally choose between UAC 1.0 or UAC 2.O mode and of course decide on the audio input. This guarantees us great compatibility and a wide range of applications. It is worth emphasizing that we will not change digital filters, or connect another DAC, or switch between regulated and fixed linear output. These are not disadvantages, of course, I just wanted to emphasize this so that people looking for these solutions know about it.


Sound:


Low tones:
In the case of the Fosi Audio K7, the overall signature is quite linear, the low tones are present and not excessively slimmed down. Such tuning allows you to focus on the music without fatigue and at the same time prevents the feeling of excessive slimming down in the sound. I especially like how easily the Fosi Audio K7 handles the low tones. The meaty and realistic character of the low tones was appreciated in particular by my headphones such as the HifiMan HE1000se. They sounded realistic, and at the same time did not become excessively dominant. Fosi focuses here on long listening sessions, which is audible, sometimes it can be perceived as slightly less control in the low tones. In particular, compared to more expensive designs, these are appearances and result from the tuning offered by the Fosi Audio K7. The whole is coherent and perfectly balances between emotions and lightness of sound.




Midrange:
Fosi Audio K7 creates a sense of a very wide stage, perfectly images and positions the sound. This is the gaming character that works great in demanding games. At the same time, the depth of sound remains at a very good level. The vocals are full and convey both emotions and you can hear them clearly and enjoy their presence. They still remain close to neutrality and natural warmth. The amount of detail is impressive, we have a lot of information here and it is perfectly distributed. So not only do we have a large sound stage, but above all it is not empty. Fosi Audio K7 does not sound like a typical bowl-shaped AKM, instead we have the perfect balance between the technical and entertainment side of the sound itself. And if someone wants, they can always adjust them using the built-in equalizer by adding bass or treble. So this is a very flexible approach to tuning itself.

Treble:
The treble is present, and in my opinion Fosi Audio K7 tends to slightly brighten the high registers. This is by no means a flaw, such tuning favors the presentation of details, and the engineers from Fosi Audio have implemented it in such a way that the whole does not tire the listener with its sound. If necessary, we can also remove the high tones using the built-in EQ. The Fosi Audio K7 has an impressive resolution for its price and shows instruments very well, especially strings or other instruments embedded in the high tone spectrum. Even my Arye Organic from HifiMan were properly controlled, sounded bright and very detailed, but did not exceed my comfort level or become tiring. It is difficult to properly brighten the upper parts and still maintain the linear and coherent character of the tuning itself. That is why I am glad that Fosi Audio has implemented this at least well in the K7 model. It is worth emphasizing here that the sound is not warmed in the way typical of older AKM systems, instead we have much more tonal balance and calmer, more linear tuning based on the technical layer and perfectly balancing between linearity and still pleasant tuning. Dynamics in the case of Fosi Audio K7 is a very strong element and makes the whole thing sound really very good, which only emphasizes how much work the manufacturer put into this project.


Comparisons:


Fosi Audio K7 VS xDuoo XA-02:
Foi audio K7 is a device focused on positioning and creating a wide sound stage, XA-02 is more mass in the sound, and a larger form of the device itself. An interesting addition to Fosi Audio K7 is the support of the microphone output. At the same time, in terms of the sound itself, Fosi Audio K7 sounds brighter and emphasizes the high tones more. Analytical and calmer presentation combined with still considerable musicality in xDuoo XA-02 is a great alternative in terms of sound and possibilities.




So who might find the Fosi Audio K7 a better choice:

• For those looking for microphone support
• For those looking for a brighter tuning
• For those looking for a preamplifier option

For whom might the xDuoo XA-02 be better:

• For those looking for a linear sound with a slightly darker presentation
• For those looking for a clean line output
• For those who prefer a large jack instead of a classic small one

Fosi Audio K7 VS EarMen ST-AMP:
EarMen ST-AMP is a device offering a fully analog balanced amplifier design, so we can connect any DAC and enjoy our favorite music. The Fosi Audio K7 does not offer such a possibility, which does not necessarily mean that it is a disadvantage, the Fosi Audio K7 was simply released as a standalone device and is supposed to fulfill such a function. Of course, the ST-AMP can also work as a standalone DAC/AMP, offering basic possibilities in terms of digital-to-analog conversion and very good possibilities in terms of the amplifier itself. Don’t get me wrong, it’s still a very decent DAC/AMP, but it gains a lot when you connect it to an even better DAC, like Tradutto. Earmen ST-AMP also tends to color our music, which is in line with the manufacturer’s intentions, it also has a fully analogue potentiometer. Fosi Audio K7 offers advanced EQ functions, microphone support and a brighter, more neutral presentation. It will also play wider, but with less depth than ST-AMP. Both devices are very good and offer great parameters.

For whom the Fosi Audio K7 may be a better choice:

• For lovers of even and brighter tuning
• For people looking for built-in EQ
• For people looking for Bluetooth support

For whom the ST-AMP may be an interesting alternative:

• For people looking for the option to change the DAC
• For lovers of more colorful playing
• For people looking for a 6.5mm jack output

Fosi Audio K7 VS Fosi Audio GR40:
This is an interesting comparison, because the GR40 is a very pleasant-sounding DAC/AMP based on two tubes and a solid circuit from ESS. The GR40, like the K7, offers support for Bluetooth and tone correction. Additionally, it offers a preamplifier output, just like the K7. However, it has significantly less power than the K7 and offers a warmer, more analogue sound signature. We will not find balance on the headphone output or microphone support in the GR40. At the same time, the Fosi Audio K7 offers more tonal balance and a cooler, wider sound. However, you won’t find the specific tube sound present in the GR40 in the Fosi Audio K7.


For whom the Fosi Audio K7 may be more interesting:

• For those looking for more power on the headphone outputs
• For those who love more neutral tuning
• For those who love a wide sound stage

For whom the Fosi Audio GR40 may be a better choice:

• For those who love tube warmth
• For those who look for a more intimate sound stage
• For those who love vocals

Summary:
Fosi Audio K7 is a great piece of equipment at a reasonable budget. Fosi has really offered a lot. We have not only a great DAC on board, but also a lot of power. The device also supports Bluetooth, but still without LDAC, which I consider a disadvantage. Fortunately, we also have other connectivity options, such as reliable USB C, coaxial or optical input. On the output side, all I lacked was a large jack to be completely happy. Fosi Audio K7 offers a slightly cooler, but still natural and very detailed sound, with excellent imaging and above-average sound stage width. Additionally, the small housing is a really great product and not only for gamers. This is an excellent solution especially for people looking for an all-in-one device offering a lot of possibilities at a relatively low price. Excellent parameters go hand in hand with gaming connectivity, and in addition the manufacturer announces a very decent price range. That is why I encourage you to check this interesting project with your own ears and evaluate it yourself. As for me, despite the slightly cooler tuning, Fosi Audio K7 really appealed to me and showed great potential. I definitely missed a large jack, but this is not a flaw, rather an emphasis on individual preference.




Strengths of the Fosi Audio K7:

• Excellent positioning, separation and sound imaging
• Neutral, but still not dry tuning
• Microphone support
• Extensive EQ options
• High power

What I would improve in the Fosi Audio K7:

• I would add LDAC support
• I would like to see a large 6.5mm jack and support for a fixed line output

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Fosi Audio K7 Headphone Dac/Amplifier
Review by Tyler

Hello readers, my name is Tyler. I am an experienced IT Administrator with a newer found love (~5-10 years) for hifi and home av, specifically in the last few years with the rise of class D amplification and affordable quality products. My background of course includes traditional IT and software, vehicle audio and electronic installation, consumer electronic support and service, as well as consumer electronic sales. I feel as if I may bring a younger and unique perspective to what you may find in a traditional review, as I have grown up in and worked the majority of my career around tech, and do not come in with as much “old school” av experience. This is not to say I have not heard or appreciated class A amplification or older speaker design, and I have certainly heard/worked with many high quality products. I do however have a love for finding those wonderful “middle ground” or “bang for your buck” products that surprise and excel for a reasonable price. This in large has led me down the path of Fosi, as you will see below, and to reaching out to become a product tester for them.

For reference in my review, I am going to list of some of the audio products I use day to day, and specifically highlight what was used in/compared to in this review of the K7, so as people can benchmark what to expect, or possibly relate to.

Home Theater:
Elac Debut Reference Bookshelves (DBR62) - Current
Elac Debut Reference Towers (DFR52) - On order, awaiting arrival
Sony SSCS5 bookshelves - Spare Room
RSL Speedwoofer 10E - Current
Sony SSCS9 - Spare room
Wiim Ultra Streamer - Current
Wiim Amp - Spare room
Fosi Audio V3 Mono x 2 - Current Power amps
Fosi ZA3 - Used in past
SMSL AO300 - Used in past
SMSL PL100 CD Player - Current

Desk/Headphone Setup:
Marantz HD-DAC-01
Beyerdynamic DT880 Premium 250 Ohm - Main Headphones
Streaming from windows PC, spotify app primarily, over optical.
Sennheiser GSX-1000 - Used in Past

For the sake of the review I also went out on a limb to use this K7 as a proof of concept and gauge my SO’s setup at her desk, and give her an intro to the headphone space.
For reference her setup (including the Fosi K7) is as follows:
Same streaming setup
Fosi K7 Headphone Dac/AMP (Optical, USB, and Bluetooth)
Sennheiser HD599 32 Ohm headphones

Anyways, with my background and some insight out of the way, I’d like to begin with my initial impressions on design and build quality, as well as the unboxing experience of the K7. I am no stranger to Fosi products and have come to appreciate their fairly simple but effective and attractive packaging, to which the K7 was no exception. It arrived well packaged and with no major blemishes.





The package includes the needed accessories to get you up and running on a PC with a USB connection, but the ports and flexibility for playing via bluetooth or an optical in, which I preferred the most. If any minor critiques on the product packaging it would be nice to see a longer USB cable as the included one is a bit too short for a nicely cable managed run I found, and though not necessary I would love to see an optical cable in the box as well. Given the expected price of the unit, I totally understand the exclusion, but nice to haves nonetheless. The amp itself is very simple and minimally designed which I loved, while still providing ample IO and interfacing to make it extremely usable with simple key inputs. The knobs, buttons and screen feel of good quality, and the unit has a nice weight to it, without being bulky. I'm sure it could be taken in a bag as a nice mobile unit if that were desired, however I would not call it “portable.” The chassis itself is made of a mix of metal and plastic and has a smooth finish overall, with no rough or sharp edges. The included power supply (yes I am one of those people who pays attention and cares about these things) seems to be ample size and specification to drive this amp with ease, and inspires confidence for longevity.

Now for the meat and potatoes of this review, how does it sound and how does it compare to some other units, and what is it like to live with/operate this unit? I would like to start by saying I am pleased to say this amp is a joy to operate. No additional clunky software or proprietary elements are required. Just plug it in your preferred method, configure Windows so as to get the device as your default in your needed applications, and you are off to the races. Out of the box with no adjustments or software based EQ, I was shocked by how similar this amp performed and sounded to my much more expensive and tenured HD-DAC-01. Of course, for those familiar, Class D amps of this form factor do take on a certain sound that is hard to explain to those unfamiliar, similar to listening to computer recreations of instruments or sound effects rather than the real deal live. I am happy to report that this device did not give me much of any of that feeling. It provides realistic natural and neutral tones, with an ample amount of power to drive my 250 ohm headphones to an uncomfortable level before noticing any distortion or detriment to the sound. The added tone controls built in give some easy to use on the fly adjustability when you need a further punch of bass, or some extra vocal clarity. This becomes very useful when switching between music, movies, communication, or video games. The same goes for the Sennheiser 599s I tested, where they sounded full and wide with no distortion, and have been a delight to tinker with, as well as providing an introduction to quality audio and Hi-Fi for my girlfriend. I’ll include some photos of each setup below for reference.


For those here for cliffnotes feel free to skip along, but I wanted to share a little more specific insight into the types of music/media I enjoy and how this Amp has handled them. I primarily enjoy EDM and Metal music, but have a love for all music of most Genres, though I may not be an avid Jazz or Classical listener. With a little bit of boost on the bass side this amp provides an exciting powerful performance, and showcases many of the more fine details in electronic music. The strums of a guitar or bass are rich and detailed in country and classic rock, and provides plenty of power for kick drums and vocals of metal music. I also do a fair bit of Gaming, to which I have recently been enjoying Elden Ring and Monster Hunter Wilds. I was blessed to have two games with an excellent musical score and sound environment design to be fully immersed in their worlds, as well as the flora and fauna. In the best way, this amp does a great job of being adaptable and disappearing, allowing the forethought of my attention to be on the content, without feeling like I need to fiddle or tinker with the sound to get it just right. For the competitive gamers, I am happy to report that the directional sound and staging was also very accurate, certainly more so than my Marantz, to where I found I could better locate where sounds came from both vertically and around me.

As to not go on and on about too much specifics, I would like to lay out some of the Pros/Key Strengths I have experienced, and some of the areas of improvement I see for future products from Fosi. I’m sure I could go on for days about every little thing with this unit, but I will keep it brief and approachable

Pros:

• Excellent sound at an extremely affordable price point
• Great design and interface
• Flexible use for all forms of media content
• Good build quality and included accessories
• Nice size and proportions for desk use
• No need for extra software or installation beyond cabling
• Works with a wide variety of headphones and speakers (Which I currently do not own/use at my desk, but plan to add some powered monitors down the road)
• Simple and effective packaging shipped straight to consumer

Cons/Areas to improve:

• Longer included USB cable for setup flexibility
• I worry about support for higher impedance headphones (EX 600 Ohm) as power may not be enough for them. Granted, this Amp would not generally be a “match” for that level or price tier of headphone
• For some, software may be seen as helpful or convenient, and may be a drawback considering there is none “included”
• Tone control is super helpful, but as someone who is used to a 10-20 band eq, it would be nice to see more than just Treble and Bass options.
• I would love to see an auto shutoff after x amount of time option, even if there is only one non adjustable option
  

To review, the Fosi K7 Headphone Dac/Amplifier has been a delight to live with and test, for not only me but also my significant other. It provided an easy to use, and wonderfully sounding experience at what will be a very affordable cost for anyone interested. It is a continuation of the excellence I expect of Fosi, and due to all of this, I believe I am at risk of it being stolen from my desk permanently by my girlfriend once this review period is over. I believe this speaks for how approachable and wonderful the current space of Hi-Fi is, and excites me of what is possible and coming in the future. Fosi continues to be a trailblazer in their space and will continue to have me as a customer in the future, product testing aside. If you are on the fence or considering this product, I highly recommend diving in head first on it, but be warned, if you are new to the hi-fi space, as I suspect many looking at this product may be, it is certainly a slippery slope.

★ Introduction :-

Fosi Audio brand is not very old or unfamiliar. They were established in 2017 in Shenzhen, China.They are basically an established brand which managed by Shenzhen Foresight Technology. Fosi audio's main target from its inception was how to win the hearts of budget audio lovers. Interestingly, they continued this trend and started marketing all the products. I'm pretty sure that the affordable price range of dac dongles, mini desktops, tube amps and other daily essential audio gear are able to satisfy their target consumers well. Besides, they always try to give good value for money items. So far I've reviewed two of their budget dongles that seemed to offer good sound value in my opinion. Recently fosi audio released the new hype created K7 dac amp with the gaming dac amp tag. I have been using this dac for more than two weeks on a regular basis so here I'm sharing my complete usage experience.



★ Disclaimer :-

First of all, I would like to thank @Fosi Audio for sending me this review sample. I had no financial agreement with them to promote their product. So the entire opinion of this review is completely my personal.

★ Box content at a glance:-

The unboxing experience of the K7 dac amp was very surprising, at least I thought it was unimaginable from a product of this price segment. Fosi audio K7 comes with a big black color box. When you open it, you will see K7 dac amp, usb A to c cable, bluetooth antenna, single end terminated headphone splitter, Dc 12v power adapter & lastly there is a user manual guide. So it is understood that fosi audio has released this dac as a complete package. But yes, they could have provided the coax cable here, but they did not provide it for cost cutting. I think this kind of unboxing experience of a dac in such a price range will be able to surprise anyone.



★ Design, Build Quality & Functionality :-

Fosi audio K7 dac amp is made with a fully aluminum alloy chassis. Even though it is a budget dac, they have not compromised on the build quality. The design language of K7 is different from the rest of the dac amps in the market and its hand feel & finishing has also been done very perfectly by fosi audio. It can be said that it will catch anyone's attention at first sight. Moreover, I have already said about the build construction that it will give a very solid feel and will bring ease of use. When you look at the device, the first thing you will notice is its two multi-functional sound adjustment knobs and some buttons. Since we are talking about knobs, I will say that yes, the two knobs are definitely effective in practical life because the one on the left side provides volume adjustment as well as gain switching, and the knob on the right side provides bass, treble, and mic control. In my use case, I found the problem with these two knobs to be wonky feedback and it felt like it would open up a type situation. Actually, there was no such problem lol but I would say that fosi audio should have implemented the knobs in a more robust way so that there is a tactile feel when rotating them.

Interestingly, if you look closely between these two knobs, you will see a small 1.5 inch LCD screen peeking out. Which is really functional because this display allows you to easily see the sound sampling rate as well as all the inputs at a glance. Also, the multifunctional button pressing was a bit frustrating, but not unusable. Anyway, now it's time to learn about the operation of these buttons.The device has five buttons and they are responsible for different operations respectively. The leftmost button can perform three functions, which are to switch to on/off & uac mode. The next button is used to give input by pressing it. The button right next to input has two types of output selections, regular for headphone and extra output option for rca respectively. The next bypass button enables & disables the eq option and lastly, pressing the 'tone/mic' button sends control to the right knob for bass/treble & microphone mode. Apart from that, three different ports can be seen on the front side of this dac, which are mic, single end & bal port, and there are some more ports on the back where if you look closely, you will see that there is a port for rca output and next to it there is a port for attaching a bluetooth antenna, coaxial port, optical input, usb c port and even the option to provide power input. Since the device does not have an inbuilt battery, it will be operated with the Dc 12v power adapter that comes with it. One of the key strengths of the K7 is its compatibility. I have tested it on PC, iPad & Android phone and it works well everywhere without any hassle like driver installation. Hopefully at least those who will purchase the K7 will be at ease from this aspect.

★ Specifications :-




★ Tested With :-

~ Sennheiser HD660S2
~ Sennheiser IE900
~ Sony IER M9
~ Dunu Zen pro
~ Moritz Dragon
~ Dunu Falcon Ultra
~ Tanchjim Origin
~ NF acous Nm20
~ Letshouer S08
~ Dunu Kima 2
~ Kefine klean

★ Sound Aspect :-

K7 offers both wired & wireless functionality in terms of sound segment. This device has support for Bluetooth 5.0 along with several wireless codecs such as SBC, AAC, aptX, aptX HD and aptX LL but sadly the Ldac codec is missing here. Those who are used to using special codecs like ldac will definitely not be able to benefit much from this. Although the latest aptX LL has a max bitrate of 1200kbps which is capable of decoding sample rates up to 96khz in wireless mode. The good thing is that it has a Bluetooth antenna, which will maintain fairly stable connectivity at a distance of around thirteen meters. On the other hand, its performance in wired mode was exceptional. Its internal section has specs like AKM4493SEQ with XMOS XU208 & QCC 3031 + TPA6120 which can decode up to PCM 384kHz - 32bit/DSD256. I doubt if any other budget dac amp at this price point has such specs. However, not just in terms of specs but in terms of real life experience, it has really delivered the expected sound performance. Talking about the sound signature of K7, I would say it is semi U-shape sounding where bass & treble along with mid forward characteristic is found. Talking about the sound in details let's jump to the bass at the beginning. In the bass section, k7 seems to be mainly sub bass focused and the mid bass position is slightly in the back seat but the presence is quite well understood. Sub bass is a very strong place and as a result deep & impactful bass rumble is available from here with a surprising amount of depth.

I didn't see any kind of exaggerated situation there but yes I did notice minor bleed with the lower mids which is not too annoying as it doesn't affect the clarity too much. Along with sufficient speed in the bass region, this k7 has shown the ability to retain a decent amount of texture which creates a quite pleasing experience. Interestingly, it is possible to enhance the bass using its right side knob, so it can be easily tweaked from here as needed.The midrange presentation is clean & forward, especially in the upper mids region. In addition, the sub bass' minor bleed in the lower mids lends a hint of warmth touch which helps create fullness in the vocal section. Many may think of this as a slight coloration, however the emotional factor of the mids of the fairly well tuned AKM chip can be said to be well present here. However, it's worth mentioning that I expected a bit more sense of space in the female vocal compared to the male vocal, but that may have had to be sacrificed to cover up the recession.

Overall vocals timbres were quite natural & detailed which was no room to complain about. Again, the performance of the K7 in the treble section was rock solid. There was very good extension from lower treble to upper treble, there was no roll-off issue as a budget dac amp which is a good thing. The treble has decent maturity in air & sparkle so there was no unwanted spike in the upper registers. Where the presence of details can be found along with a slight smooth manner, similarly the detail retrieval of the lower treble was fairly good. The bass and treble control levels are also linked to the same knob, which also offers customization. In terms of technical ability, the K7 is quite impressive, the sound stage was quite wider & spacious, with a slight lack of stage depth which could have been better, but I didn't notice the lack of width. On the other hand, the imaging & stereo separation were excellent. The positioning of the tiny -large scale instruments is very precisely located and their natural environment across the left & right channels gives an immersive experience. Beyond that, the micro dynamics punch was quite enjoyable and the macro dynamics seemed a little more overshadowed. Also, the tonality & timbre accuracy is slightly colored but not too unpleasant to listen to.

★ Microphone & gaming :-

Regarding the microphone, it really depends on the mic quality. Normally, the mic supported cables we use for gaming compensate very well and can provide clean output. However, it is important to remember that if someone uses studio grade mics, especially those that are widely known for recording, they will not get the expected results from this. The good thing is that by enabling UAC 1.0, stable mic support is available, which is a feature that Fosi Audio has included in their DAC. I noticed a noticeable delay when switching from UAC 1.0 to UAC 2.0 mode via the dedicated UAC button and the latency issue becomes even more of a problem when playing FPS games in wireless mode. It is very clear that this is not ideal for gaming as the wireless codecs do not have mic support. I really don't know how Fosi Audio is marketing this with the wireless gaming tag lol. However, the current pro level gaming headsets have some uniqueness in the function of the ports button, but for this I am not blaming the mic input of the k7, but considering all aspects, there are some limitations. However, I personally benefited most in the music listening season rather than gaming.

★ Synergy and Power :-

The DAC provides a neutral to slightly warmish tonal character that ensures good synergy when driving most earphones & headphones. The device has no shortage of output power, both single end (600mw@32Ω) & bal port (2100mw@32Ω) output power was impressive. At the same time, the harmonic distortion level was also comparatively low, resulting in a very clean sound delivered through both ports. I have used full size open back headphones with this DAC amp and have also tested several IEMs and its driving capability was exceptional everywhere. This K7 can drive maximum headphones, from efficient dd headphones to higher-impedance full-sized headphones. It has enough power to drive most headphones at moderate volumes without distortion. Fosi Audio claims it can handle 16 - 300 ohms impedance loads and deliver constant power, and my real-life testing has been fairly positive. However, you won't get clean output from this with sensitive sets, instead you'll get a hissing or noisy effect in the sound. Beyond that, very power-hungry magnetic planar headphones may be challenging to drive to their fullest potential. It is worth mentioning here that the DAC & amp section of the K7 performs well considering the budget, but I personally found the DAC section to be more impressive. In my opinion, its power output is sufficient for many headphones and even paired well with high impedance headphones like the Sennheiser HD600 series, where it maintains a decent amount of dynamics, speed & resolution, along with a hint of warmish music presentation, it can give optimal results there.

★ Conclusion :-

Fosi Audio has created the most competitive situation in the current market with the release of the K7 in their long journey of budget dac amp line up. With so many feature packed and high power output at a sub 200$ price, this mini desktop combo they are offering truly deserves the value for money tag. I can say with certainty that if someone purchases this DAC, they will be able to treat almost all the IEMs and headphones in their arsenal fairly well. So it can be said with certainty that no one will regret buying it for a moment. If someone is thinking of something compact powerhouse type in such a budget range, then I would say the k7 is the better option and I would recommend buying it.

The K7 dac amp will be officially released on Kickstarter very soon, so it would be wise to keep an eye out there for an update on exact pricing details.



I have included the purchase related informations below for everyone's convenience

Fosi Audio K7 Gaming Dac Amp

Disclaimer:​

I’m more of a Tech head than audiophile and I use YouTube Music for 99% of my listening. Take everything I say with this in mind and please don’t come after me for not having refined taste. This is purely from my silly little point of view. I was also loaned this pair for free to test and play with but all opinions are of my own with no guidance given whatsoever.

GEAR USED:​

Streaming Platform: Youtube Music Premium (Bitrate: 256kbps AAC & OPUS)
IEMs used: Moondrop starfield II
Headphones used: Philips SHP9500
Bookshelf speakers used: Edifier MR4

BOX:​

The K7 didn't come with much aside from the bare essentials. A Type C to A cable which I would have preferred to be a touch longer considering that this will probably be plugging into the back of your PC and if it’s on the floor or off to the side it might be a tough reach especially if you want to cable manage it properly. A 3.5mm mic and audio splitter for the combo jack users out there. Aside from the cables all that’s left in the box would be its Power cable and brick which are both assuming and generic looking which there is nothing wrong with except for the annoying green light on the power brick which forces me to unplug the thing when I go to bed.

BUILD:​

Shell:
The entire thing is built on extremely solid feeling Aluminum. With a nicely powder coated black exterior that’s cool to the touch and a nice premium heft the K7 definitely doesn’t disappoint in the build quality department in terms of its main body

Knobs and buttons:
All buttons on the K7 felt nice and tactile with no hint of mushiness or cheaply made switches anywhere. You’ll be certain of your key presses and won’t have to double click anything due to doubt. The same affair goes for the knob when it comes to its physical feedback. It spins indefinitely with no start or stop which I think boils down to personal preference but what is objectively good about it is that the ridges are well defined and even the CNCed little ridge on the top of the knob is easy to feel for making orienting yourself without even looking at it extremely easy to do. It’s got nice chunky steps as well which help with fine granular control without being too sensitive and I’ve never really struggled with adjusting my volume on the fly.

Screen:
The screen would be the most “meh” part of the physical build in all honesty. It looks like a cheap LCD with a hazy quality too, especially in the dark which can make the smaller elements on it like its output and input a bit more difficult to see. There’s also seemingly no straightforward way to adjust the brightness of the screen which I found mildly annoying, especially at night when I like turning the lights low and there’s just this bright orange speck on my desk. What I can say is that it’s nice that it’s angled, making it easier to read even when it’s a little up towards your desk. Overall it’s not a horrid screen but it definitely feels like it’s one of the more disappointing physical features of the device.

SOUND:​

Bookshelf speakers via RCA Cables:
Where I honestly enjoyed the Fosi K7 the most was through my Speakers. For context, I’ve only ever just plugged in my speakers to the standard 3.5mm jack of PC which sounds just fine but plugging them in via RCA definitely changed the game for me. Suddenly everything felt like it had a nice oomph to it, especially the low end. I’m not saying these drastically changed the way my speakers sounded but I can definitely tell that they’re hitting more of what they’re capable off with the K7 than without.

IEMs via 4.4mm balanced out:
While this didn’t drastically change how I perceived the music like my speakers, I can honestly say that listening to them gives me more confidence knowing that anything I plug in can be powered and listened to with a solid foundation.

Headphones via 3.5mm out:
Surprisingly these had the same effect on my headphones as they did on my speakers, albeit to a slightly lesser degree. They definitely improved the overall sound and made everything a little bit more “meatier” I guess would be the best way to describe it. Again, I want to reiterate that they didn’t suddenly turn my headphones into HD600s but it definitely makes me feel like I'm getting more out of my gear then I normally have been doing so and that’s pretty cool.

NITPICKS:​

On the Bluetooth:
While the Bluetooth input was pretty cool considering that I could just play music straight from my phone to my nicer speakers but It felt like a Bluetooth output would have been a better feature to have If I was given the choice. I can see a scenario where someone would more likely have a bluetooth speaker in tandem with earphones / headphones rather than some bookshelf speakers and for those people that feature would have been killer.

On the “Gaming” part:
Admittedly this one is a little lost on me. Aside from the UAC stuff(which is admittedly nice for our Nintendo brothers out there), I don’t really see how the other feature sets are gaming centered. You could probably argue for the mic input being one but at the same time Fosi doesn’t really explain what their “Intelligent Noise Cancellation” is in the marketing material so it feels a little brushed off to me.

On the viewing angle:
Since there’s no way to adjust the screen brightness and it can get a little bright and also a little glare-y sometimes it can be a little difficult reading the text on it at times. I would have preferred a slightly steeper angle or at least maybe a crude way to adjust it to make it a little more comfortable to read.

Final Thoughts:​

I definitely enjoyed my time with the Fosi Audio K7 and while it’s not the all in one solution I think it’s trying to be, it definitely hit a lot of boxes for me. Solid hardware with decent features that I think can be the nice cherry on top for most people.

If you find yourself looking for a central control station for your audio setup that you don’t really feel like adjusting anymore then the K7 might just be the thing to slot right in. With not much thinking needed regarding compatibility it should be a simple setup to go for in most configurations unless you have something really quirky.

But those are just my thoughts and remember that the best gear is the one that makes you enjoy your hobby the most that's within your budget.

Thanks for reading!

INTRODUCTION

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MAIN SPECIFICATIONS:

• Chipset: AKM AK4493S + XMOS XU208 +OPA1612 + TPA6120 + Qualcomm QCC3031;
• Maximum Sampling Rate:
  
  • USB: PCM 384kHz-32bit/DSD256
  • Optical: PCM 24bit/192kHz
  • Coaxial: PCM 24bit/192kHz
  • Bluetooth: PCM 24bit/48kHz
• Headphone lmpedance: 16-300Ω;
• Input:
  
  • Coaxial
  • Optical
  • USB-C
  • Bluetooth
  • 3.5mm Microphone
• Output:
  
  • RCA
  • 3.5mm Single-Ended
  • 4.4mm Balanced;
• Bluetooth Version: 5.0, Bluetooth connection Distance ≤13m, Bluetooth codecs: SBC, AAC, aptX, aptX HD, aptX LL
• Price: 180$.

WHAT’S IN THE BOX:

• DAC / amp itself - Fosi Audio K7;
• USB Type-A / C to USB Type-C cable;
• Bluetooth-antenna;
• Power adapter 12V / 2A with a European plug;
• 3.5 mm. Headphone / Mic splitter;
• User manual.

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UNBOXING & ACCESSORIES

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DESIGN & BUILD

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CONTROLS

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INPUTS

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OUTPUTS & OUTPUTS POWER

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EQ Mode

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USB Audio Class 2.0 (UAC 2.0)

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SOUND IMPRESSIONS

• Kiwi Ears Ardor (via Bluetooth)
• Cooler Master MH752 (with microphone, via 3.5mm jack)
• Celest Relentless (via 4.4mm balanced jack)
• Moondrop Blessing 3
• Simgot EW300
• BQEYZ Cloud

• USB Type-C, PC (Windows 11)
• UAC 2.0 mode
• Bluetooth (with Kiwi Ears Ardor)

SOUNDSTAGE


GAMING IMPRESSIONS

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COMPARASION

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CONCLUSION

General/Packaging/Build
Fosi Audio is a brand that hails from the mainland of China, relatively well known in providing affordable audiophile solutions with affordable price tag. They have products ranging from home audio to personal audio, i have the K7 with me today, which Fosi Audio touts as a gaming dac/amp. We shall take a look at it and determine whether it is worthy of the gaming moniker.
Build quality of the K7 is very solid, the chassis feels like aluminium with angled design for better ergonomics. There’s a small LCD that displays the sampling rate, mode, as well as tone control’s level. Buttons have very good tactile feedback and they’re not wobbly.
Packaging itself is fairly good, big box with plenty of protection to protect the K7 from impact during transportation from the courier. Within the box, you will find the power adapter, bluetooth antenna, type c cable as well as the K7 itself.



Technical Specifications grabbed from Fosi Audio’s product page

Chipset -XMOS XU208+AKM4493SEQ+QCC 3031+TPA6120
Headphone lmpedance -16-300Ω
Input -Coaxial, Optical, USB-C,Bluetooth,3.5mm Microphone
Output -RCA, 3.5mm Single-Ended,4.4mm Balanced
Firmware Upgrade -XMOS firmware can be updated via the Type-C interface
Bluetooth Version -5.0
Bluetooth Connection Distance -≤13m
Noise Floor - ≤2.5μV
Bluetooth Transmission Audio Format -SBC, AAC, aptX, aptX HD, aptX LL
Input Voltage and Current -DC 12V 2A
USB Compatible Devices -Windows 7,8, 8.1,10,11 (Driver required)Mac OS X, Linux (No driver required)
Full specification please refer to this page



IEMs/Headphones/Equipments used for this review

• Final Audio Heaven II
• Dita Mecha
• Tanchjim Origin
• Aune S17 Pro Evo Amp
• Aune SR7000

*K7 is sent by Fosi Audio for the purpose of this review, i thank them for the support and opportunity

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. I have used the Angel for several months prior to writing this review.

Notable Features

• No loud popping sound upon switching the amp on or off
• Clean and dark background, no audible noise floor
• Adjustable Bass, and Treble level on the 2nd knob
• Switchable between UAC1 and UAC2

Sound Impression (Bypass Mode without Tone Control)
The K7’s tonality is tilting towards slight warmth with very good tonal weight across the spectrum. Bass has good body, mids doesn’t sound thin, treble has good enough energy and it doesn’t sound dark



DAC Amp Combo

• Utilising the internal dac of K7, which is the AK4493SEQ, the DAC exhibited clean lows with good texture, sufficient punch and good resolution and dynamics, tonality wise, it is on the slight warm side and it has very good synergy with my transducers that has neutral and slightly bright signature, for those with neutral signature, the sound is very dynamic and enjoyable when you feel the need to tap your foot

K7 + Aune S17 Pro Evo

• Operating as DAC only, the K7’s DAC is quite capable with good dynamics and technicalities. Pairing it with the S17 Pro Evo seems to take the K7’s sound to the next level
• Soundstage is bigger with better width, height and depth perception
• But, do keep in mind that S17 Pro Evo is a flagship Class A headphone amp from Aune

Pairing impression with various Transducers (only K7 itself)
Final Audio Heaven II

• Heaven II is a single BA IEM and the tonality is slightly on the warm side and bass lacks a little extension due to it being a single BA
• Pairing it with the K7, somehow the bass sounds fuller and has a bit more extension, Heaven II is also very adaptable to EQ, pushing the Bass to +4, it has more thump and overall more fun to listen to
• Treble doesn’t change fun, mids sounds full and not thin
• Soundstage is slightly bigger and also imaging, easier to identify and pin point the instruments

Dita Mecha

• Mecha is a very powerful sounding IEM, big bass and very musical
• Big has better control and more enveloping kind of experience when using it with balanced out high gain
• Treble has slightly better extension
• Not much changes on the mids, remains thick but not muddy
• Imaging seems to be improved and also the soundstage

Aune SR7000

• Fairly efficient headphone with neutral warm tonality
• The SR7000 can be driven even with a mid tier dongle, but when paired with a more powerful source, bass exhibits better control, tighter and better texture and speed
• Mids are slightly forward with this pairing, but not in your face kind of presentation
• Treble has slightly better extension and air
• Instruments can be pin pointed easily during gaming, footsteps coming behind and moving to left or right on the rear

Tanchjim Origin Stock Nozzle

• A single DD set will scale well with good source and more power, Origin is no exception either, it is a neutral with slight warmth kind of sound profile
• Pairing it with the K7 does make the mids slightly thicker and a little bit more air
• Very good imaging and soundstage

Gaming with it

• Using the Tanchjim’s Zero Ultima with K7 for gaming, the imaging is definitely improved so as the soundstage, sub bass does rumble a little more during explosions or when they are a lot of actions going on

Final Thoughts
My experience with Fosi’s product has been good, the K7 is no exception. As a Dac/Amp combo, the AK4492SEQ does the job fairly well and also has the ability to put out up to 2.1w of power from the balanced output. It provides good enough sonic performance for users who are conscious about desk space or just want something that is all in one without spending extra on a headphone amp.
Despite bearing the gaming moniker, the K7 doesn’t have much gaming feature, only the ability to switch from UAC 2 to UAC1 for compatibility with the gaming console.
Still, without any doubt, I absolutely recommend the K7 for those who are looking for a clean and dynamic sounding dac/amp without breaking their bank.

Head to the link below if you are interested in getting a unit yourself
Fosi Audio K7 - Non Affiliated
Fosi Audio K7 Kickstater’s Page - Non Affiliated

FOSI K7 Review: ARE WE GAMING?​

KICKSTARTER PRICE: $153 (PHP. 8,300.00)​

WATCH REVIEW HERE:​

PROS:​

• The most practical Hi-Fi amplifier I’ve tried
• Fantastic power output
• Clean but lively sound
• Microphone jack support
• Informative OLED screen
• Built in EQ
• Dedicated mute button
• Solid bluetooth support
• Premium metal build quality
• Dedicated buttons for many of the features
• Intuitive controls

CONS:​

• Shakey and cheap-feeling buttons
• Not a lot of “gaming” features like app support, multi profile EQ, etc
• UAC 2.0 does not have mic support
• EQ is only limited to high and low shelves
• No LDAC support

WHO THIS UNIT IS FOR:​

• People looking for a practical HiFi amplifier
• People who want a feature rich desktop amplifier
• People who want microphone support on their HiFi amplifier

WHO THIS UNIT ISN’T FOR:​

• People who want an amplifier with a smaller footprint
• People who want more gaming oriented features
• People who want a simple amplifier

SHORT REVIEW: ​

While not as focused as a gaming amplifier, the K7 is one of the most practical amplifiers I’ve ever tried. Mic support, an informative OLED screen and a powerful but clean sound on a sub $200 amplifier is something that was not in my bucket list of 2025, but I’m glad it exists. I really cannot think of one “con” about the K7 besides the fact that its “gaming” features are lackluster compared to its HiFi features. HIGHLY RECOMMENDED!

FULL REVIEW:​

We may be too late to explore the world and too young to explore the universe, but we live in a timeline where a desktop amplifier can have great sound quality, sufficient power to even power headphones, microphone support, a crap ton of other features including a dope LED screen all for potentially under $200.

Shilling aside, the K7 has been a seriously versatile device that has changed my perspective on just how practical yet high quality audio amplifiers can be. I’ve always attributed audio devices like these to be extra effort for little gains, at least for casual use. But I haven’t used a device as my main “source” of amplification as much as I did without feeling like I need to change my entire set-up just to get it to work properly.

So today, let’s talk about the K7 and all of its glory, but also what can be improved to potentially make the ultimate “gaming” desktop amplifier.

FOSI K7 SPECIFICATIONS:​

Chipset - XMOS XU208 + AKM4493SEQ+ QCC 3031 + TPA6120
Maximum Sampling Rate:

• USB: PCM 384kHz - 32bit/DSD256
• Optical: PCM 24/192
• Coaxial: PCM 24bit/192khz
• Bluetooth: PCM 24 Bit / 48kHz

Headphone Impedance: 16 - 300 ohms

Input: Coaxial, Optical, USBC-C, Bluetooth, 3.5mm Microphone

Output: RCA, 3.5mm Single-Ended, 4.4mm Balanced

Bluetooth Version: 5.0

Bluetooth Connection Distance: Less than or equal to 13m

Bluetooth Transmission Audio Format: SBC, AAC, aptX, aptX HD, aptX LL

Input Voltage and Current: DC12V 2A

BUILD AND INTERFACE​

The most “gaming” aspect about the K7 is the build and interface. Hell, a friend of mine even said it looked like a DJ booth and I don’t blame them. This rectangular, angled and chiseled look is distinctive to only Fosi with their somewhat industrial designs.

The K7 is, by far, their most “unique” designed amp that I’ve tried as it leans closer to a more futuristic design, similar to what HiBy is doing. This is evident with the orange highlights being placed in a way that looks very eye-catching.

However, the highlight is that OLED screen, which is something I never knew I wanted in an amplifier, but now I actively look for in my future purposes. It’s such a practical thing to see not only your current connections and decoding, but allow for the K7 to be as feature rich as it is. More on that later.

As for the quality of the interface themselves, they feel alright. The knobs in particular are a little shaky and the interface buttons feel a little cheap. I would be fine with it if it wasn’t for the fact that the cheaper SK01 has more confident buttons than this. Not to worry, it does feel durable enough for a few years of aggressive volume changes without issue.

Features​

The K7 is jam packed with features that overwhelmed me with just how much I can do with this. Let’s talk about them one by one.

Built-in EQ​

The first thing that you’ll probably play around with the K7 is the EQ. Yes, the K7 has built in EQ which can be toggled by pressing the TONE/MIC button. This brings up the bass and treble values that both go from +12 to -12.

The way that the EQ was implemented here were low and high shelves with the low shelf having a more drastic change than the high shelf, as expected for ear safety. You can drastically change the bass profile without introducing boxiness and bloat as long as the headphones you’re EQing aren’t already bloated to begin with. The subtle treble boost can also add much needed sparkle or cut down energy pretty damn well. This is almost equivalent to adding an impedance adapter on certain IEMs. Ideally, you wouldn’t want to crank the values all the way up or down (especially on the bass), but it’s a nice way to see just how far your headphones can get equalized. This is a decent value and one that should be more than enough for basic adjustments that physical EQ knobs would do. Looks cooler than those, though!

But what if you don’t want to do EQ but you also don’t want to reset the profile you have? Bypass mode! It’s a dedicated button that allows you to disable the EQ without needing to reset the values. Once you want to go back to your EQ profile, just press that bypass button again!

It would have been nice for more profiles to be added in order to just swap between profiles depending on the vibe/headphones you’re pairing the K7 with, but the bypass mode is nice in of itself.

I should also note that the EQ only works on UAC 1.0 and not on UAC 2.0. I can’t confirm exactly why UAC 2.0 cannot support EQ (and the microphone as I’ll talk about soon) as UAC 1.0 seems to exist only for backwards compatibility and devices that only support UAC 1.0 like the Nintendo Switch, but as it stands, you’re limited to UAC 1.0 when enabling the EQ. Speaking of UAC;

UAC Button​

One thing that has been present in many DACs, including dongles, is the option to switch from UAC 1.0 and 2.0. UAC 1.0, from what I’ve researched, is mostly used when pairing with devices like the Nintendo Switch, but also allows for microphone support in tandem with the audio output.

I first came across this with the Simgot DEW4X with its occasionally working microphone support. The K7 makes the process very linear and easy to understand as all you need to do is press a single button and you’d be able to see on the OLED screen whether you’re in UAC 1.0 or UAC 2.0.

My only gripe is that, on top of the delay when switching modes which breaks the flow of listening, UAC 2.0 seems to have an odd delay when switching between tracks. I initially thought this was an app thing as I was using MusicBee on Windows, but this also happened in Spotify.

Thankfully, this is only present when switching between tracks and not the transition between tracks. It would have been a massive con for me if it did.

OLED Screen​

I’ve talked about the features of the K7 that use the 1.5 inch OLED screen, but I want to talk about just how practical this thing is, especially if you’re a file junkie and love to know about the sample rate. On top of that, you can also see what connection mode you’re in so you know if the device is broken or you’re just on the wrong connection mode.

My only gripe is that the sampling rate can only be seen if you’re in UAC 2.0 in USB mode. It’ll only show if you’re in PCM or DSD mode on UAC 1.0 with no information on whatever file you’re decoding. This isn’t really a dealbreaker, but one that I’m curious as to why it wasn’t included.

Regardless, that OLED screen is a standout as I haven’t experienced a desktop amp with such a feature.

Bluetooth​

The bluetooth feature of the K7 is a rather basic Bluetooth 5.0 system that can only decode up to 24bit/48kHz with aptX. While it might seem lackluster, I’d say that it’s perfectly justifiable considering the focus of the device.

LDAC would have been a nice addition, considering how great this sounds on wired, but it’s not a dealbreaker for me. aptX HD being capable of at most 576 kbit/s decoding is perfectly fine considering most of my streaming is done through Spotify as most of my playlists are there. However, I will acknowledge the purists who want LDAC and unfortunately, the K7 will not suit you.

Connection quality is pretty good, albeit occasionally stuttering on my PC during normal use. It could be an issue with my bluetooth dongle, but either way, it’s a generally stable connection.

The main thing I want to point out is the latency being surprisingly good. While watching movies or playing games, I didn’t think the bluetooth delay was long enough to affect my experience. The sound, most of the time, matches my inputs and what happens in front of the screen. This is thanks to the QC3031 Bluetooth chip allowing for a decent bluetooth listening experience.

Microphone Input​

The one aspect that baffled me the most about the K7 was the microphone input. Normally, desktop amps in this category of the audio space lean towards either end of the quality-convenience spectrum. Either you get all the audiophile features or all the practical features.

The K7 combines both of that with the microphone input that seems to be a big part of the K7’s identity, gaming amplifier and all. It comes with a dedicated volume and mute knob that will show on the OLED screen its current volume level.

The quality of the microphone will depend on the microphone that you pair it with. Pairing it with in-line or boom-style microphones is great as it provides enough power while minimizing distortion, audio bleed and interference. However, audio-bleed (audio from your headphones bleeding into the mic) is still dependent on the headsets that you’re using.

However, I wouldn’t recommend pairing this with a condenser microphone as it doesn’t really provide enough power to give the condenser microphones the proper amplification. Anyone who’s owned a 3.5mm condenser microphone should be aware of this.

This then brings me to the aspect of the microphone that I’m not that big of a fan of. First is the fact that it’s UAC 1.0 limited. While I understand that UAC 1.0 is necessary to allow for microphone support, it somewhat defeats the purpose of making the listening process linear when you have to switch between UAC 1.0 and UAC 2.0 if you want to use your microphone.

Another issue that I have that isn’t necessarily a fault of the K7 is that most external microphones and even gaming headphones nowadays use USB for their interface. While there are still a lot of gaming headphones that use TRRS and lapel mics that use 3.5mm make the perfect pairing with the K7, it would have been insane if Fosi had included a Type C Microphone input on top of the 3.5mm microphone input with this. This would have instantly made it a must-recc for literally every single person on this planet. This leaves another USB slot for your PC and makes the K7 a proper all-in-one device.

Lastly, the bluetooth input does not have microphone support. Not really a dealbreaker, but bummed those who have bluetooth headsets could make the K7 an easy way to minimize the cables to their PC.

Regardless, I’m not complaining about the fact that the K7 has a microphone input and I am so thankful that Fosi is closing the gap between practicality and audio quality with this. Speaking of audio quality;

SOUND ​

Output Specifications​

3.5mm

4.4mm

Listening Experience​

DISCLAIMER:​

I would like to preface this by saying that most of my listening was done on USB UAC 1.0 and UAC 2.0 as well as Bluetooth. This is because I wanted to focus my testing specifically on how I personally use it. I never used the coaxial and the RCA function, but I will make an updated post on how this works.

The thing that bothered me about amplifiers was just how difficult it is to properly pinpoint the differences between each other as good amplifiers are meant to playback music through headphones with linearity and clarity. Colored amplifiers are for poorly made or tube amplifiers.

That being said, the K7 sounds clean as hell. While my perspective on how good desktop amplifiers can get changed since I got the SK02, I can’t deny that the K7 has a certain level of cleanliness that not even the SK02 has.

The best way I can describe how the K7 sounds compared to every other amplifier I’ve used is a really good piece of linen canvas. It’s a clean, flat and linear surface where once you begin to paint, all the colors come to life and blend perfectly when you want it to and stand out when it needs to.

The K7 is quite literally a blank canvas of an amplifier that, no matter what headphones or earphones you pair with it, you will get the best listening experience you’d have with those headphones. Straight up, it does what a good amplifier does.

The low end can be tight or punchy, depending on the track and headphones. The mids are consistently clean, nuanced and transparent on tracks and headphones that bring about that clarity and cleanliness. The treble is snappy, lively but smooth and polished on tracks that are equally smooth, but it doesn’t overly emphasize the sharpness on even poorly mixed tracks. Obviously, the headphones are 95% the sound in this equation, but even then the K7 somehow finds a way to make the headphones more enjoyable by not overemphasizing the bad aspects of the headphones more than cheaper or poorly implemented amplifiers.

This cleanliness also allows for your headphones to perform at its best when it comes to their individual technical ability and headphones with impeccable separation and layering will be perfectly played through the K7. I seriously could not find an aspect of the K7 where it sounded “lacking”.

Power Output​

The highlight has to be the power, however. 600mW on 3.5mm and 2100mW on 4.4mm on high gain is literally the most power that I’ve ever had on an amplifier. Both the SK02 and DC03 maxed out at 1400mW and this goes even higher? I don’t even have a pair of headphones that can utilize 2100mW of power! That only means that you will never struggle with driving and pair of headphones here. The impressive part is how well it handles volume scaling for how powerful it is. I’ve had amplifiers in the past that were either too soft or too loud at low volumes and the K7 is not that. It’s not as fine as something like the SK02 where the differences in volume is so fine that most IEMs regardless of impedance and sensitivity will have a perfect volume spot, but it’s good enough.

Pairing​

This makes the K7 essentially a universal pairing with basically any IEM/headphone that I’ve tried. Normally, I’d feel the need to highlight a specific pairing with an amplifier that I review, but the K7 is so versatile and uncolored that basically anything that you want to hear in its full glory and in its best clothing, you’d pair it with the K7. Besides the SK02, I can’t say the same for other amps I’ve tried.

Noise and Distortion​

I didn’t find the K7 to distort even at higher volumes (at least to my hearing capability), however, it does have an occasionally audible noise floor for very sensitive IEMs. It’s not super audible, but having nothing playing in your IEMs makes the noise floor a little audible.

It’s a seriously good sounding amplifier with enough power for basically anything that doesn’t need a transformer to run.

COMPARISONS:​

vs SK02​

I’ve been talking about the Fosi SK02 as a main comparison for the longest time in the review, but how does it really compare?

Well, fundamentally, the K7 is what the SK02 would be if it was buffed 100 times and catered to a more practical market. However, I’m also aware that the SK02 is a completely different product category to the K7.

This is evident with the existence of the K5 Pro, but since I don’t have that, I have to compare these two.

And realistically, sound wise, the SK02 and the K7 both present music in such a linear yet lively way. It’s neither clinical nor colored and it emphasizes the best aspects of the IEM or headphone that you pair with the amplifier.

The main sound difference would come down to the difference in output and how the K7 edges the SK02 just a little bit more in cleanliness, particularly in the treble region.

With the obvious physical differences like the SK02 not having the OLED screen and only featuring a single knob on top of the countless features the K7 has, it’s clear that the jump in price is justified.

Regardless, the SK02 fulfills the budget-friendly audiophile better than the K7 and the K7 is a far more practical and powerful device for power users and “gamers”

CONCLUSION:​

Every other amplifier and DAC have become irrelevant to me because of the K7. I said the same thing about the SK02 and the K7 did to the SK02 what it did to every other amplifier that I’ve owned.

The K7 is quite simply the ultimate desktop amp for a person like me who spends most of their time on the desk working or studying. Powerful, feature rich and practical are the best ways I can describe the K7.

However, that doesn’t mean the K7 is a perfect device. The small nitpicks with the knobs and buttons along with the occasional delays and maybe even the fact that despite being a “gaming” amplifier, it doesn’t really have much gaming features like what other dedicated gaming brands would offer. Lack of LDAC is also a shame, but one that is understandable with how feature rich it already is. But I would argue that the K7 is more catered to practical-minded audiophiles who might be into gaming as well.

But fundamentally, this is just a really good desktop amplifier. A bit tedious and cable-rich? Yes. But powerful, practical and versatile? Absolutely. That’s what makes the K7 stand out from every other amplifier I’ve tried

Thank you for reading my full review on the Fosi K7. As of the current moment, the K7 is on Kickstarter here: https://www.kickstarter.com/projects/fosiaudio/fosi-audio-k7-gaming-headphone-amp-dac

Fosi Audio K7 Gaming DAC/Amp Review
1. Introduction
• Background
In late 2024, I had the privilege of receiving the soon-to-be-released flagship product from Fosi Audio—the K7 Gaming DAC/Amp. After just two weeks of use, it completely replaced my HyperX Cloud III wireless gaming headset, which had been my trusted audio companion for over a year, becoming my primary audio device. Designed specifically for gamers, the K7 maintains Fosi Audio's hallmark of exceptional sound quality while being deeply optimized for gaming scenarios. Whether it’s the precise capture of footsteps in FPS games or the immersive environmental soundscapes in action games, the K7's performance is nothing short of impressive.
• Market Position
Traditional gaming sound cards often rely on standard 3.5mm headphone and microphone jacks, aiming to accommodate the needs of most gaming headsets. Meanwhile, devices with a 4.4mm balanced output are usually found in the realm of Hi-Fi DAC/Amps, catering to users with higher demands for sound quality and driving power. The Fosi Audio K7 cleverly bridges the gap between these two categories. It retains high-quality sound performance while addressing the unique needs of gamers. Supporting high-fidelity audio output and optimized for convenient in-game voice communication, the K7 allows users to enjoy both Hi-Fi audio quality and gaming performance in a single device.
• Cross-Category Innovation
As a hybrid device targeting both gaming and Hi-Fi markets, the K7 offers unique advantages in sound quality, functionality, and gaming experience. In the following sections, I will provide a detailed evaluation of its features and real-world performance based on my hands-on testing, covering functionality, sound quality, and user experience.



2. Official Specifications and Features

• Input/Output Interfaces
  • Front Panel: 3.5mm microphone input, 3.5mm headphone output, and 4.4mm balanced headphone output.
  • Rear Panel: RCA output, Bluetooth antenna port, coaxial input, optical input, USB input, and 12V external power input.
• Bluetooth Features
  • Supports Bluetooth 5.0.
  • Compatible with Bluetooth formats such as aptX HD, aptX, AAC, and SBC.
  • Sampling rate: 48kHz / 24-bit.
• EQ Adjustment
  • Frequency split point: 1000Hz for high/low-frequency adjustments.
  • Adjustable range: ±6dB for high frequencies, ±12dB for low frequencies.
• Gain Function
  • High/low gain modes, accommodating headphones with varying impedance.
• BYPASS Function
  • A dedicated button toggles the BYPASS mode.
  • When BYPASS is enabled, the device bypasses internal high/low-frequency adjustments, outputting raw audio signals.
  • When disabled, the device resumes and applies the previously set EQ adjustments.
• 4.4mm Balanced Headphone Output Performance (UAC)
  • Rated Power: L+R ≥ 2100mW + 2100mW (32Ω load, THD+N < 1%).
  • Signal-to-Noise Ratio (SNR): 121dB (A-weighted).
  • Total Harmonic Distortion (THD+N): 0.0002% (A-weighted).
  • Dynamic Range: 121dB.
  • Noise Floor: < 6.5μV (A-weighted).
  • Frequency Response: 20Hz-20kHz (±0.2dB).
• 3.5mm Headphone Output Performance (UAC)
  • Rated Power: L+R ≥ 600mW + 600mW (32Ω load, THD+N < 1%).
  • Signal-to-Noise Ratio (SNR): 122dB (A-weighted).
  • Total Harmonic Distortion (THD+N): 0.0005% (A-weighted).
  • Dynamic Range: 121dB.
  • Noise Floor: < 2.5μV (A-weighted).
  • Frequency Response: 20Hz-20kHz (±0.2dB).
• RCA Line Output Performance (UAC)
  • Output Voltage: ≥ 2Vrms.
  • Signal-to-Noise Ratio (SNR): 121dB (A-weighted).
  • Total Harmonic Distortion (THD+N): 0.0005% (A-weighted).
  • Dynamic Range: 121dB.
  • Noise Floor: < 3μV (A-weighted).
  • Frequency Response: 20Hz-20kHz (±0.2dB).

3. Design and User Experience

• Materials and Craftsmanship
  • Full aluminum alloy body with CNC unibody construction.
  • Surface treated with sandblasting for a refined finish.
• Design Highlights
  • Separate volume knob and microphone volume knob for precise control.
  • Equipped with a 1.5-inch LCD display.
• Portability and Practicality
  • Dimensions comparable to a smartphone, slightly shorter in height than the SK02.
• Aesthetic Design
  • Maintains Fosi Audio's signature orange-and-black color scheme.
  • A futuristic design with a subtle touch of tech-inspired aesthetics.

Comparison with the SK02

• Operational Experience
  The K7 inherits the knob design of the SK02 while adding an additional knob, resulting in a more versatile functional layout. The left knob is used for volume adjustment and gain control, while the right knob focuses on microphone volume and EQ adjustments. Both knobs are similar in size and tactile feel to those on the SK02, offering a consistent operational experience.
• Enhanced Interface
  Compared to the SK02, the K7 takes the user interface a step further by integrating a 1.5-inch LCD display in the center of the knobs. Featuring a black background with orange text, the display provides a clear and intuitive view of the current status. Below the screen are five functional buttons corresponding to UAC mode, input mode, output mode, BYPASS function, and high/low-frequency adjustment toggles. The control logic is simple and intuitive, making it easy to master with minimal practice.

• Portability and Functionality
  It’s worth noting that the K7 requires an external power supply. Although its compact size remains an advantage, its portability is slightly reduced compared to the SK02. However, the K7 makes significant advancements in functionality, making it more suitable for desktop audio setups and multi-scenario usage.

Minor Design Flaws

• Microphone Limitation
  The microphone can only be used in UAC1.0 mode, which may limit its functionality in certain scenarios.
• Port Spacing Issue
  The spacing between the microphone jack and the 3.5mm headphone jack is somewhat tight. This could pose a challenge when attempting to simultaneously connect devices with larger plugs.

• Inconsistent Volume Adjustment
The volume values change irregularly during adjustment, such as 30, 32, 33, 36, 38. This inconsistency may not be ideal for users who prefer precise and uniform control, especially those sensitive to such details.


4. Sound Performance (Without EQ Adjustment)
I. Overall Sound Signature
• Tuning: Neutral and balanced, with no noticeable coloration.
II. Frequency Response
1. Low Frequencies
o Excellent depth and extension with moderate quantity.
o Superb control, delivering clean bass without a boomy or overwhelming sensation.
2. Mid Frequencies
o Vocals are full-bodied and positioned appropriately.
o Instruments exhibit clear texture and well-defined layering.
3. High Frequencies
o Good extension with a natural and delicate presentation.
o Rich in detail without sounding harsh or fatiguing.
III. Soundstage and Imaging
The K7 offers a spacious soundstage with a balanced and layered distribution. Its horizontal soundstage feels expansive, while the depth is moderate, effectively conveying changes in front-to-back distance.
IV. Detail Retrieval
The K7 excels in resolution, reproducing fine details in music and gaming audio with precision. Even in complex audio scenarios, it maintains clarity.
• Noise Floor: Exceptionally clean background with no audible noise.
• Separation: Outstanding layer separation, with smooth and natural transitions between frequency ranges.
• Distortion: The low-distortion design ensures highly accurate sound reproduction, even during dynamic shifts or in detail-critical moments, resulting in a natural and authentic listening experience.
V. Comparison with Fosi Audio’s SK02
The K7’s sound performance is highly consistent with that of the SK02. Both share a balanced and neutral tuning, demonstrating excellent compatibility with high-impedance, low-sensitivity headphones. Despite using different chipsets, the K7 has a slightly warmer tonality compared to the SK02, but the difference is minimal. Without a direct side-by-side comparison, the variation is almost imperceptible. For most users, the sound performance of the K7 and SK02 is remarkably similar. Both cater well to users seeking accurate reproduction and balanced sound. If you already own the SK02, upgrading to the K7 purely for sound quality may not be a necessary decision.

Tested Headphones: Sennheiser HD660S, Sony MDR-V6, Audio-Technica R70X



5. Sound Performance in Competitive Gaming
I. Sound Performance in Competitive Gaming
HyperX Cloud III
• Sound Signature
o Tuning: Close to the Harman curve, offering ample low frequencies with good depth and fast transient response, resulting in dynamic bass. However, it can feel slightly overwhelming at times.
o Mids: Clear vocals with a balanced positioning, though occasional sibilance occurs, especially in scenes with rich high-frequency details.
o Spatial Presentation: Excellent sense of space, with clear localization and distance cues, making it suitable for basic FPS gaming needs.
o Drawbacks: Higher distortion, less defined instrument separation, and somewhat lacking detail and layering.
• FPS Gaming Performance (CS2)
o Default "Natural" EQ setting delivers bright and impactful gunshots, though they can feel overly pronounced. Footstep directionality is good, enabling clear identification of enemy positions and distances. However, the overall sound lacks naturalness—footsteps feel slightly hollow, and jump-landing sounds can be harsh. High-frequency weapon-switching effects, like "knife sounds," are particularly noticeable. Adjusting the headphone EQ by reducing 8kHz by approximately -4.5dB significantly improves these issues, reducing harshness and sibilance.
• FPS Gaming Performance (Valorant)
o Footstep localization remains vague and lacks fullness, with insufficient layering. Enabling in-game HRTF surround sound greatly enhances spatial perception and separation, improving footstep clarity and directional accuracy. However, distant subtle sounds can become overly amplified, complicating distance estimation.

K7 Paired with HiFi Headphones
• Sennheiser HD660S
o Default sound is slightly heavy, with muffled footsteps and gunshots, and average directional and distance performance. Adjusting the K7 EQ (+6dB high frequencies, -1dB low frequencies) improves footstep clarity and widens the soundstage. Overall, it performs better than the HyperX Cloud III, though its footstep clarity still slightly lags behind.
• Audio-Technica R70X
o Natural sound with excellent positional and distance accuracy. Gunshots and footsteps retain some of the R70X’s signature "warm blur." Even without EQ adjustments, the R70X outperforms the HyperX Cloud III. Changing the in-game EQ from "Natural" to "Crisp" or adjusting the K7 EQ (+1dB high frequencies, 0dB low frequencies) further enhances footstep clarity.
• Valorant Performance
o Using the same EQ settings as for CS2, the footstep clarity, directionality, and distance perception are highly accurate. Skill sound effects and footsteps are well-separated. In complex scenes, enemy positions can be quickly discerned. Disabling the HRTF surround sound feature is recommended to avoid excessive sound clutter near the ears, which can affect distance and spatial perception.

II. Microphone Comparison
HyperX Cloud III
• Performance
o Clear and bright voice capture with excellent noise reduction, effectively eliminating environmental noise (e.g., fan noise, keyboard clicks). Overall, it ranks highly among gaming headsets.
K7 with Microphones
• BOYA M100
o Slightly warm vocal tone with a hint of smearing. The sound feels more distant but remains clear overall, with good noise reduction. While slightly inferior to the HyperX Cloud III, it is still acceptable.
• Microphone integrated into wired earphones
o Average voice capture quality with slightly muffled vocals. However, it is still adequate for voice communication and gaming.

III. Summary
• Sound and Spatial Performance
In popular FPS games, the K7 paired with HiFi headphones outshines gaming headsets in both sound quality and spatial localization. Comfort during extended gaming sessions is another significant advantage. Recently, I spent 12 hours straight playing Immortals of Aveum with the R70X, an experience that would be unbearable with the HyperX Cloud III due to its 330g weight compared to the R70X’s 210g.
• Wireless vs. Wired
Despite the K7's superior performance with HiFi headphones, there is one area where it cannot compete: the freedom of wireless. Modern wireless gaming headsets, with 2.4G receivers, have achieved impressively low latency. Although a slight delay is still perceptible compared to wired setups, it is negligible in gaming scenarios. The convenience of wireless freedom—grabbing a snack, getting a drink, or even visiting the bathroom without removing the headset—is hard to overlook.

Ultimately, the choice comes down to priorities: precise sound performance or flexible, convenient usage.


6. Compatibility and Bluetooth
• Compatible Devices
o Supports PC, PS5, Switch, and other devices.
o No driver download is required, making it very convenient to connect to PCs or other devices.

• Bluetooth Connectivity
o Based on the chipset, it is presumed to support Bluetooth 5.0.
o During FPS gaming, there is a slight delay between gunfire sounds and game visuals, but this is negligible for watching movies or TV shows.
o Bluetooth connection is stable, with no occurrences of disconnections or audio-video desynchronization.
o The Bluetooth functionality is particularly convenient when occasionally connecting the K7 to a smartphone or tablet.


7. Target Audience
• Who Should Consider the K7
For users who want to balance competitive gaming and high-quality audio—especially those who own hard-to-drive over-ear headphones—the K7 is an excellent value-for-money choice. It offers a near-complete solution through a single device. However, for users who already own the SK02 or primarily use easy-to-drive in-ear monitors, the K7 may not be as compelling. That said, gamers who specifically require external microphone functionality might find the K7 worth considering.
• Crowdfunding Launch on Makuake
Notably, Fosi Audio launched the K7 project on the Japanese crowdfunding platform Makuake on January 16, 2025. For those interested, the Makuake page provides more detailed product information and support options. If the K7 has caught your attention, be sure to visit the following link to learn more and support the project:
https://www.makuake.com/project/fosik7/


8. Conclusion
• The Fosi Audio K7 strikes a perfect balance between sound quality, versatile functionality, and powerful driving capability, making it an excellent choice for both gamers and HiFi enthusiasts. It continues Fosi Audio's signature neutral tuning style while significantly improving functionality and user experience. With robust support for high-impedance headphones, it easily adapts to various usage scenarios.
• The K7's upgrades over the SK02 are primarily in its functional layout and adaptability, while the differences in sound performance are minimal. If you’re seeking better sound quality, richer functionality, and stronger driving power for premium headphones, the K7 offers exceptional value. However, if you already own the SK02 or prioritize portability and wireless convenience, a wireless gaming headset might be a better fit.
• Ultimately, the K7 is a device that successfully balances sound quality and functionality, catering to users who want to enjoy both gaming and music. The final decision depends on your specific use cases and personal preferences.

Here is the buy link for this producthttps://www.kickstarter.com/projects/fosiaudio/fosi-audio-k7-gaming-headphone-amp-dac?ref=itsgreq

Fosi Audio K7 Gaming DAC/AMP Review: Are We Sure?​

Disclaimer:​

Good morning, readers! Today we are here with a brand new product from Fosi Audio, a DAC/AMP with very interesting specifications, the Fosi Audio K7. I just reviewed the Creative SoundBlaster G8 so the comparison becomes very interesting indeed. Products like the Fosi Audio K7 can be appreciated even more because they fully express the efforts of a smaller brand to compete with the giants. We are not on par in terms of extra features but everything else is actually superior in quality. Calling this product suitable for gaming is wrong because the audio quality of the K7 is far beyond. Despite the lack of “surround” technologies, the K7 creates an immense stage.

The review, as always, will be completely unbiased, uninfluenced, and free of affiliate links.

I would like to remind you that I am just a person who enjoys trying out new items and listening to a lot of music; I am not an expert.

My opinions are obviously subjective.

Tech Specs:​

• AKM AK4493S DAC: High-resolution audio with low distortion, enhancing in-game sound effects and delivering studio-grade music quality.
• XMOS XU208 USB Controller: High-speed digital audio processing for synchronized game audio and visuals, plus clean signal transmission for music.
• OPA1612 Op-Amp: Improves positional audio accuracy in games and provides low-distortion sound with rich detail for music.
• TPA6120 Headphone Amplifier: Powerful headphone-driving capability for both low- and high-impedance headphones, ensuring impactful sound and pure audio quality.
• Qualcomm QCC3031 Bluetooth Chip: Supports aptX LL low-latency for gaming and aptX HD lossless for near-wired HiFi wireless listening.

4.4mm Balanced Headphone Output:

• Rated Power Output: L+R ≥ 2100mW + 2100mW (32Ω/THD+N<1%)
• SNR: 121dB
• THD+N: 0.0002%
• Dynamic Range: 121dB
• Noise Floor: ≤ 6.5μV
• Frequency Response: 20Hz-20kHz (±0.2dB)

3.5mm Single-Ended Headphone Output:

• Rated Power Output: L+R ≥ 600mW + 600mW (32Ω/THD+N<1%)
• SNR: 122dB
• THD+N: 0.0005%
• Dynamic Range: 121dB
• Noise Floor: ≤ 2.5μV
• Frequency Response: 20Hz-20kHz (±0.2dB)

RCA Output:

• Output Level: ≥ 2Vrms
• SNR: 121dB
• THD+N: 0.0005%
• Dynamic Range: 121dB
• Noise Floor: ≤ 3μV
• Frequency Response: 20Hz-20kHz (±0.2dB)

I hope this list is helpful! Please let me know if you need any further clarification or information.

System Requirements:​

I have not found specific information but what I can tell you is that the product works without problems with OSX but that it has a totally independent volume not controllable by Mac. I think it can be solved with a firmware update to be done probably using a Windows PC where the drivers are installed. In general it works with any device because it does not need to be powered.

Packaging:​

The Fosi Audio K7 packaging is very simple, all black but the product is well protected. Inside it is everything you need to put it to work right away.

• Fosi Audio K7
• BT antenna
• Power Supply 12V 2A
• 1 Cable Type C to Type C/USB
• Mic + Aux splitter
• User Manual

Much more intelligently than Creative, Fosi has put a cable with a built-in USB adapter (it has been using it for a long time) and it is the most wonderful accessory you can find. The Fosi Audio K7 has its own power supply of 12V 2A. We also find a BT antenna.

There are no other cables but what is there allows anyone to use it immediately.

Build Quality/First Impressions:​

Since I also own the old Fosi Audio K5 Pro, I wonder if it’s really the same company. The leap in quality is so huge that I can hardly believe it’s still them. The K5 Pro compared to the K7 is a toy. Even taking the more recent Fosi SK02 as an example, you can perceive a further evolution in the care of their products. You can tell that it’s a company that listens to its customers and that carries out surveys regarding the features they want.


The Fosi Audio K7 is a high quality product, all in CNC machined metal, I don’t think there is anything plastic. The weight of the product itself is an indication of the amount of metal that has been used. Compared to the Creative G8 where even the knobs are plastic. The attention to detail can be seen in the precision that the buttons have in their seats, how precisely the volume knobs rotate and the rubber feet underneath that bear the Fosi branding (perhaps even excessive as a thing). But honestly, it’s nice to see a brand put so much effort into it, especially knowing where they started from.

On the upper part we find in the middle a small but use OLED display, two knobs the first for the volume and the second for the adjustments.

Below we have 5 buttons for the management of the Fosi Audio K7:

• UAC Mode
• Input
• Output
• Bypass/Direct
• Tone/mic adjustments

On the front we have microphone input, 3.5mm output and 4.4mm output. The presence of the balanced output makes me extremely happy.

On the back the comparison with the Creative Sound Blaster G8 is not on par. The Fosi Audio K7 has Bluetooth though. For the rest we have Coaxial, Optical and RCA outputs

Oled Display

Special Features:​

Let’s say that the features are definitely basic if compared to the Creative but for my non-gaming use, the ability to adjust the highs and lows is already very interesting. The thing I like is that you don’t need software but everything is manageable with the buttons and knobs.

Even the microphone can only be adjusted in its volume. Compared to the Creative SoundBlaster G8, the gaming features for modern games are limited. But if you use it at an audiophile level or for some old-school games or films, the story is completely different.

Sound Signature & EQ:​

The AKM AK4493S combined with the TPA6120 does a perfect job; in fact, right away it seemed to me that the stage compared to other models tested was particularly more accurate. The sound is basically very detailed and analytical with a warm note. Everything sounds extremely coherent and if there was a need for more brightness or anything else, you just need to correct the tones. I personally really like it in direct mode and I think it will become my reference DAC/amp for the tests from now on.

Unfortunately, there is no real full equalizer or presets you can use.

Power:​

Power is more or less comparable to the Creative SoundBlaster G8. I don’t know how it’s possible in reality but in terms of power, the Creative is more impressive, which, from a simple USB brings out capacities far superior to many of the competition. The Fosi Audio K7 has its own separate power supply so there is absolutely no lack of current. I simply believe the volume control is more precise and therefore does not give you “slaps” of volume like the other. So I believe it is only a matter of acoustic perception but in both, it is difficult to reach the maximum volume. In my case, the maximum I have tried is the EPZ x Tipsy Starn One with 64 OHM of impedance and at most you can reach 30 of volume out of 62. Regardless of what is connected to it, it is powered and driven perfectly.

Considerations after a month of use:​

In the new setup that I will do in a few months this product will have a key role on the desk. In the future it will become a point of reference for my future reviews, its sound and the possibility of controlling the tones quickly and quickly allows you to test the IEMs and headphones that I will have the opportunity to test. The sound, even if you should not notice big differences with other dac / amp, has a care and precision that I had never heard on the others. The totally silent background even with very sensitive IEMs like the Simgot EA100 Fermat make it suitable for any user. Compared to the Creative, the gaming DNA takes a back seat, this product is in all respects first and foremost a high-level HI-FI product. You can perceive the care and research that they are employing in improving their products. The definition that the Fosi Audio K7 brings out adds points to the soundstage.

The only downside might be the audio jacks on the front. This requires more desk space than is necessary on the front.

Fast Comparison:​

Looking at the past of Fosi Audio and the present of other brands, the comparisons become interesting.

vs Fosi Audio K5 Pro


I seriously have a hard time believing it’s the same company. The K5 Pro is a product that borrows a standard size chassis with minimal customization. You’ve probably seen a thousand amplifiers with the same chassis on AliExpress. A product that has a totally different quality that can’t even be compared. In terms of input and output, it can still be improved, but in terms of design, functionality, and build quality, it has made giant steps.

I’m not telling you about the sound because the K7 sounds 1000 times better.

vs Fosi Audio SK02


A more recent product from Fosi but that still, even if perhaps a year old, makes it clear how the company is growing and in which direction. I find the SK01 brighter but not for this reason: it is more detailed and suitable for critical and analytical listening. In terms of construction quality, you can perceive a connection with the two products. In terms of sound, the K7 is a few steps above and is also much more powerful.

vs Creative SoundBlaster G8


A fusion or joint venture between the two brands would create the definitive product for gamers and audiophiles. It will probably never happen but if the Creative features were to be merged with the Fosi Audio build quality, it would produce a definitive product for most users. Undoubtedly the versatility of the inputs and outputs is superior on the Creative, even the app support and the features designed for gamers or streamers are very advanced. If all this is not what you need, the Fosi Audio is really well made. I have no particular needs for gaming so I probably don’t see the real limitations that a gamer might experience.

Conclusions:​

In the case of minimal desks, I think a product like the Creative Soundblaster G8 could be very appealing. I am not a person who can identify with a desk with a minimal setup but surely in the near future I will have to drastically reduce the complexity of the setup I currently use. The thing I liked the most is the possibility of maintaining a single sound card for both my PCs and also sharing the two Pebble X speakers via wired connection. Before, I used them via USB only with one of the two and the other had to make do with the BT connection. The features with the DSP activated are multiple but I am more of a purist in that sense. Usually my favorite mode is the direct mode, where there are no colorations of the sound. Great that they finally managed to bring an update of the Creative APP on OSX but there is still a long way to go for it to be on par with the Windows one. As for gaming, the features present are more designed for streamers or creators.

In my opinion the Fosi Audio K7 has a sound that is anything but gaming but very Hi-Fi, I think one of the most complete and full I have heard so far. Are we sure it is a gaming DAC?

More information is here:​

• https://fosiaudio.com/pages/fosi-audio-k7-dac-amp
• https://www.kickstarter.com/projects/fosiaudio/fosi-audio-k7-gaming-headphone-amp-dac

Disclaimer
Please note that I am not an audiophile, and this review does not delve into the technical aspects of the DAC/Amp. My impressions are based on my personal preferences, and others may have different experiences with this product. I also have a very limited experience with audio products so please take this review with a grain of salt.

The FOSI K7 was lent to me as part of a review tour.

Price: 155 USD (Kickstarter) / USD (Retail)
Link: https://fosiaudio.com/pages/fosi-audio-k7-dac-amp

Part 1: General Product Details

Package Inclusions:

• The K7 DAC/Amp
• DC 12v power supply
• USB-A/C to USB-C cable
• Bluetooth antenna
• 3.5 headphone splitter
• User manual

General Specifications

• Input: Coaxial, Optical, USB-C,Bluetooth,3.5mm Microphone
• Output: RCA, 3.5mm Single-Ended,4.4mm Balanced
• Bluetooth Version: 5.0
• Bluetooth Transmission Audio Format: SBC, AAC, aptX, aptX HD, aptX LL
• Chipset: XMOS XU208+AKM4493SEQ+QCC 3031+TPA6120
• Headphone lmpedance: 16-300Ω
• Input Voltage and Current: DC 12V 2A

Audio Parameters

• 3.5mm Headphone Output
  • Rated Power Output: L+ R≥600mW+600mW (32Ω/THD+N<1%)
  • SNR: 122dB
  • THD+N: 0.0005%
  • Dynamic Range: 121dB
  • Noise Floor: ≤2.5μV
  • Frequency Response: 20Hz-20kHz (±0.1dB)
• 4.4mm Headphone Output
  • Rated Power Output: L+R≥2100mW+2100mW (32Ω/THD+N＜1%)
  • SNR: 121dB
  • THD+N: <0.0002%
  • Dynamic Range: 121dB
  • Noise Floor: ≤ 6.5μV
  • Frequency Response: 20Hz-20kHz (±0.1dB)
• RCA
  • Rated Power Output: ≥2Vrms
  • SNR: 20Hz-20kHz (±0.1dB)
  • THD+N: 0.0005%
  • Dynamic Range: 121dB
  • Noise Floor: ≤3μV
  • Frequency Response: 20Hz-20kHz (±0.1dB)

The DAC/Amplifier

• The body of the K7 is made up of cnc-ed aluminum, while the knobs and buttons are made of plastic. The knobs have tactile bumps per step and have around 20 steps each. The knobs are also clickable and has a tactile bump and an audible metallic click when you do.
  • On the front of the K7 are:
  • 3.5mm microphone input
  • 3.5mm headphone output and
  • 4.4mm balanced headphone output
  • On the rear of the K7 are:
  • DC 12V power
  • USB-C input
  • Optical input
  • Coaxial input
  • Bluetooth antenna (input)
  • RCA output
• On the top are two 3.5cm stepped knobs and a small 1-inch LCD that shows information on currently used settings and connectivity.
• The left knob controls volume when turned, and toggles gain level when pressed. The right knob controls input mic volume, and tone adustment for treble and bass when turned, and toggles mic mute when pressed.
  • Below the knobs and LCD are 5 buttons:
  • On-Off/UAC: turns the K7 on and off. If the K7 is on, this button toggles between UAC1 and UAC2
  • Input: toggles between the possible inputs
  • Output: toggles between RCA and headphones (either 3.5mm or 4.4mm - NOTE that it is NOT recommended to use 3.5mm and 4.4mm at the same time)
  • Bypass: overrides the bass and treble tone adjustments if you changed them. Use this to hear the natural sound of the K7
  • Tone/Mic: Toggles between bass and treble for tone adjustment, and can also control microphone volume if on UAC1

Part 2: Subjective review

Setup #1 - PC Gaming

• Source: PC (thru USB C to A)
• Headphones: Philipa SHP9500
• Games: Overwatch 2, Marvel Rivals, Subnautica

Setup #2 - Mobile Gaming

• Source: Xiaomi Pad 5 (thru Bluetooth 5.0)
• Headphones: Philips SHP9500
• Games: Wild Rift, AFK Journey, CoD: Mobile, Wuthering Waves

Test Notes

• Due to a recent ear infection I am opting to use headphones for this review.
• I will be using my iFi nano iDSD LE for comparing, as it’s the only desktop DAC/Amp that I own.
• As much as possible I will be using the BYPASS output as to only hear the natural sound of the K7.

General Usage Impressions

• The K7 heats up quite a bit, but with the power it’s about to output I think it’s normal, especially since it has an aluminum case.
• As a gaming DAC/Amp, the feature that I expected to be there isn’t. It’s called “Chatmix” (like the one on the Steelseries Arctis 5) or GameVoice (like the one on the Soundblaster G8)
• There’s definitely a splitsecond delay when using the Fosi K7 on Bluetooth mode. This is very apparent when pulling the trigger in CoDM and the explosion comes in a little late so I can’t recommend using this on Bluetooth mode.
• As mentioned, the soundstage and holographic imaging of the K7 is excellent! Combined with the easy tone-adjustment of changing the bass, footsteps and in-game skills used in Overwatch 2 and Marvel Rivals was much more easier to hear coming. As a support main in both games, it’s always pesky to know when a Sombra or Spider-man is about to jump you.
• Subnautica is another atmospheric game where you play as a stranded astronaut on another planet, forced to scavenge for your survival mostly underwater. It gets a little too real when you hear the water behind you suddenly bubbling.
• All in all, non-Bluetooth gaming with the K7 is a treat and can give you an advantage if paired with the right headphones, people might even accuse you of using wallhacks!

Sound Impressions

• Right off the bat, the Fosi K7 sounds strong, orchestral music sound fuller. Musical details and and clarity is excellent.
• The details are clear and holographic, it’s definitely immersive.
• Despite my headphones already being open back and therefore offers some good soundstage, the K7 enhanced that a bit more, and the sound felt wider in comparison to what I already hear from my ifi DAC.

Nitpicks

• I have a keyboard with a knob that I use for volume control and mute/unmute. The K7 at times ignored any changes to the volume as well as muting/unmuting. I installed the provided driver here (link provided to us by Ryan of the Fosi team), but after a while it occurred again.
• The K7 has a 3.5mm microphone input on the front panel. I wish the microphone input was on the back instead, as it’s cleaner.
• The Bluetooth functionality of the K7 is for receiving audio (connect your phone or DAP to it), not transmitting audio (connecting to bluetooth headphones/in-ears). This would have been nicer especially if you have a wireless PCVR setup.
• The 3.5mm microphone input is in the front. Would have been better to have it at the back for less cable clutter in the middle of the table. A USB or XLR input for the microphone would have been nice as well but maybe that’s asking for too much?

Other Notes

• Maximum volume stops at 62. Sounds like a very arbritrary number right? They gave us the following explanation:
  

  Our product manager said that the maximum volume is 62%:
  

  1. Limited by the amplification level of the main control chip;
  2. Based on point 1, if the volume level is designed too fine, the number of rotations will increase.

  Click to expand...

• The K7 is another device you have to manually turn on after you turn on your PC or console. It won’t turn on automatically since it uses external power.
• I was confused what the UAC 1 and 2 were for at first but here’s the gist: UAC1 (USB Audio Class 1) supports up to 24-bit/96kHz audio with limited bandwidth and broader compatibility, while UAC2 (USB Audio Class 2) will disable microphone input in exchange for higher resolution, lower latency, and better synchronization. UAC 1 is present on the K7 because some consoles like the PS5 don’t support UAC2 yet, which makes UAC1 essential for GAMING DACs.

Final Thoughts
The Fosi K7 is a functionally versatile but powerful DAC/amp, that punches above its price point. It’s a highly capable HiFi device with a wide soundstage, excellent holographic immaging, and immersive sound. And while it falls short of expectations with regards to gaming features, it’s no big deal as the Fosi K7, even if not marketed for gaming, will still be an excellent choice, especially with the discounted kickstarter price, making it a solid option for audiophiles and gamers looking for a budget-friendly HiFi experience.

I’m definitely looking forward to the next product Fosi makes, hopefully it’s going to have more gamer-centric features! Oh and next time, maybe some RGB for the 10% FPS boost? /s

Foss Audio K7 – Gaming DAC Amp



For the passive consumers:

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Disclaimer & Unboxing:

Fosi Audio sent me another toy to play with, in exchange for my opinions.
The K7 ‘Gaming DAC Amp’.

It has been designed from the ground up to be the ultimate upgrade from the Fosi Audio K5.
Let’s see if it lives up to it’s promise.

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Build & Design

The entire shape and design isn’t just a departure from the old K5, but an almost total rethinking of what it means to design a desktop audio interface.
To get right to the point, it is a very human design.

Just think about it.
When you reach out to change the volume on a forwards facing knob, you’re limited to use your thumb and one or two fingers in an almost awkward, unnatural twisting motion.
When the controls are on the top of the device, this allows you to take control with almost all your digits in a very natural and comfortable position that isn’t far from their natural resting position on the keyboard.

Of course, Fosi Audio isn’t the first to do this, but it’s great to see more adoption.
The K7 therefore, has two, extra large, ribbed, black knobs that you can easily command with your sweaty gamer paws.


The entire body, knobs and buttons are CNC milled aluminium alloy and it has some nice heft to it, which makes it easier to plug in your headphones without shifting the entire device backwards, and the top plate and all controls are angled towards the user.

Overall I think it looks great. While it might be too much of a departure for traditional audio enthusiasts, and might look to ‘gamer’, it is backed up with a rock solid build.
On the front of the device is 1 microphone input and 2 headphone outputs, 3.5mm and 4.4mm balanced.

On the rear is an almost full assortment of inputs including USB, coaxial, optical and Bluetooth which also supports the lossless aptX codec.
Also is an RCA out so you can use the K7 as a pure DAC for other devices.
And I do mean a pure DAC. When RCA-out mode is enabled, the headphone output stage is disabled and completely bypassed.




Also on top of the K7 are 5 control buttons and the all-important Fosi-Audio-orange-themed LCD display.
To be clear, unlike full analogue amplifiers, the K7 is so full of features and controls that you absolutely do need to learn how to use it, and use the screen to use it.
There are a few controls you can learn to use blind, with some muscle memory, but others are not so simple.

Controls
Knobs
• Left knob twist - Volume control
• Left knob press - Toggle High/Low Gain
• Right knob twist - Treble/Bass/Mic volume
• Right knob press - Toggle Microphone Mute

Buttons - From left to right:
• On/off UAC – Short press to turn on, long press to turn off.
- When it’s on, short press switches between UAC1 and UAC2 modes.
- UAC2 mode is more for higher-end audiophoolery but the microphone input is disabled.
- UAC1 mode enables the microphone and microphone volume control.
• Input – simply cycles through all inputs.
• Output – simply toggles between headphone or RCA out.
• Bypass – more audiophoolery here; this mode bypasses the tone controls
• Tone/Mic – In UAC1 mode, this cycles between Bass, Treble and Microphone volume.
- In UAC2 mode, it simply toggles between Bass and Treble volume.

Out of all the controls, I think the first button might be the most important to learn quickly.
Finally after around 2 or 3 weeks I’m finally remembering the short press for on and long press for off, and of course the short press when on to toggle UAC modes.

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Using it daily & The Sound

I’ve been using the K7 as my daily driver since it arrived on my doorstep and I’m somewhat enamoured with it.
Previously I would alternate between the NFB11.28 and the SK01/SK02 combo, both equipped with ESS DAC chips, depending on what headphones I was using and how much raw power I needed.

The K7, with it’s AKM chip honestly doesn’t sound so different to my ears. Maybe there are people who can hear the subtle differences between DACs, but it’s usually lost on me.
I can however report that the K7 performs with much of the same authority and musicality I experience with the NFB11.28, which is an improvement over the SK02.

I still had to either switch to the audio-gd or K7’s RCA out to the SK01 if I wanted to use some of my headphones with a 6.3mm plug, but since these are marketed towards desktop gamers, I assume this won’t be a common problem.
I was also impressed with the high volume capability of the K7. Even out of the weaker 3.5mm output, the 600mW @32 Ohms is enough power to easily drive an HD650, but I still feel that large planars do sound better when given more from the powerful balanced output with it’s 2.1 Watts @32 Ohms, which is great if you already have a balanced cable, but was a bit of a bother for me, since I’ve mostly got either 3.5mm or 6.3mm plugs on my higher end full size headphones.

The main volume control is excellent.
It is a stepped digital control.
Every step you feel in the knob controls one ‘step’ in the amp.
• From 0-24, every volume step is in 3s.
• From 24-52, every step is in 2s.
• And from 53-62, every step is in single digits.
This gives you a really well designed balance between control and convenience.

The right control knob for treble, bass and microphone volume all works in single steps.
Treble from -6 to +6, bass from -12 to +12 and microphone from 0 to +10.

The microphone input has some noise reduction and overall worked fine for me, although I don’t have a use for this as I use my Rode NT-USB microphone for that sort of thing.
I’m also not sure how well the noise reduction works because I don’t live in a noisy environment and it’s just not that interesting for me.

Tone Controls
The tone controls however was more of a hot topic and something I was very interested in hearing.
The K5 had some very decent tone controls for the price and size of the device, but ultimately was a coloured amp.
The K7 is an improvement over the K5 in that regard, with what sounds like an almost perfectly neutral output when no tone controls are applied.

This graph shows the stock/neutral output of a Sennheiser HD650 measured on a miniDSP EARS, shown in green, compared with tone controls at both their maximum and minimum extremes, shown in grey.
Purple lines show inverted max and minimum values (e.g. – max bass + min treble).



Here is another graph with K5 tone controls overlayed, shown in blue.
The K7’s bass control has more swing in both directions, but less in the treble.
I think this is fine.
There was never any moment I felt that the K7 didn’t have enough versatility in the treble.
A significantly more important topic is the affected range.
The treble is fine. No complaints there.
The bass however is not great.



I was really impressed with the K5’s bass control when I reviewed it last year.
It only significantly manipulates bass up to around 300-400hz and remains fairly linear in the way it focuses on raising lower frequencies over higher bass, effectively adding something close to a bass-shelf.

The K7, affects a larger range, with a non-linear focus that humps at around 100hz.

Unfortunately, this can directly contribute to headphones sounding boomy instead of deeply thunderous or authoritative.
If your goal is only to make small adjustments, then it’s totally fine, but big corrections, like those I made with the K5 for the infamous Sony MDR-SA3000 are just not tasteful with the K7.

As a 'DAC/Pre-amp'
I also gave the K7 a good run as a standalone DAC which was chained to the Fosi Audio SK01 for occasional 6.3mm use, or as pre-amp + tone controls to my STAX SRM-313 (feeding STAX SR-Lambda & Kaldas Research RR1)

I found nothing to complain about this combo, as the K7, much like my other favourite Fosi Audio amps, have a dead-silent background and can pair very well with ultra-revealing electrostatic headphones through which I detected no audible background humming or hissing even at full volume.
Only the most hyper-sensitive IEMs will be able to pick up a very quiet background hissing that only plays when audio is playing, and disappears about 10 seconds after playback stops. It was undetectable with all my headphones and IEMs, but it’s something to be aware of.

And finally, using Bluetooth as the source input is only recommended for music listening, as there was some delay between video and game action on screen - although this could be due to my outdated Bluetooth dongle adapter.

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Conclusions

If you’re looking to move up from your simple entry level DAC amp combo and you either need something with more power or much more versatility, there aren’t many options at this price point.

This is one of the most powerful amplifiers around under $200, one of the most feature-rich, and most importantly, it doesn’t slouch in musical performance.

Link to the kickstarter purchase page

The Fosi Audio K7 is an intriguing device that manages to blend high-quality audio with gaming-focused performance seamlessly. It’s packed with features and functionality, earning it the nickname I’ve given it—Fosi’s “Swiss Army knife of audio.” From its multi-purpose design to its rock-solid hardware, the K7 is built to handle a variety of use cases while delivering a surprisingly immersive and enjoyable sound experience.

I put the K7 through its paces, using the USB input as my primary connection and running a mix of my go-to test tracks alongside my daily Tidal playlist. After hours of listening, I can confidently say this little device is more than just a jack of all trades—it’s a master of quite a few. It left a lasting impression on me, offering versatility and audio quality that exceeded my expectations.



Whats In The Box? Here is a quick unboxing video of the Fosi Audio K7.











The build quality of the Fosi Audio K7 is exactly what you’d expect from the brand—rock solid and built to last. The thick metal body gives it a sense of durability, and it’s surprisingly hefty for a gaming DAC/amp. The moment you pick it up, you can feel its sturdiness and quality.

One of my favorite touches is the tactile notches on the knobs. Every turn feels precise and satisfying, adding a sense of precise conotrol that complements the overall premium build. It’s the kind of design that not only looks good but also feels great to use.

Fosi Audio designed the K7 with both functionality and ease of use in mind, making it an excellent option for anyone who values versatility without unnecessary complexity.





Sound Performance

At the heart of the K7 lies the AKM AK4493SEQ DAC chip, implemented thoughtfully to balance musicality and analytical precision. It retains AKM’s signature warm and natural tonality but adds a level of detail and imaging that stands out. The soundstage is impressively wide and deep, giving tracks an expansive sense of space and clarity. Imaging is precise, allowing instruments and effects to be pinpointed effortlessly within the mix.

Despite the extra layer of detail, the sound never feels clinical. It maintains a smooth, engaging quality that is easy to listen to for hours. Whether you’re gaming or enjoying music, the K7 delivers a sound signature that feels both dynamic and refined.

Interface and Build

Fosi Audio truly nailed the design of the K7, making it both intuitive and user-friendly. The multifunction control knob is a intuitive feature, allowing you to seamlessly switch between tone controls and the mic input, different outputs and inputs of your choosing. It’s straightforward enough that even those who skip the manual can figure it out quickly. The orange LCD display is a nice touch, giving you a clear overview of your settings at a glance.

Beneath the control knobs, you’ll find five multifunction buttons, each serving a specific purpose:

1. Power and UAC Mode: The first button powers the K7 on and off and toggles between UAC 1.0 and 2.0 modes, depending on your device’s compatibility.


2. Input Selection: The second button lets you switch between USB, coaxial, optical, and Bluetooth inputs.


3. Output Selection: The third button determines your output—headphones or external devices like RCA. On the front panel, you can also toggle between the 3.5mm and 4.4mm headphone outputs.


4. Bypass Mode: The fourth button activates bypass mode, disabling the tone controls to give you the pure, unaltered sound of the DAC chip.


5. Control Mode: The fifth button toggles between microphone volume, bass, and treble adjustments. These can be fine-tuned using the second knob, while the first knob is dedicated solely to controlling the main volume.


The build quality of the Fosi Audio K7 is exactly what you’d expect from the brand—rock solid and built to last. The thick metal body gives it a sense of durability, and it’s surprisingly hefty for a gaming DAC/amp. The moment you pick it up, you can feel its sturdiness and quality.

One of my favorite touches is the tactile notches on the knobs. Every turn feels precise and satisfying, adding a sense of precise conotrol that complements the overall premium build. It’s the kind of design that not only looks good but also feels great to use.

Fosi Audio designed the K7 with both functionality and ease of use in mind, making it an excellent option for anyone who values versatility without unnecessary complexity.







As a DAC Amp Preamp

Using the K7 as a DAC preamp for my passive bookshelf speakers, paired with the Fosi Audio MC331 tube amp, the synergy was remarkable. The K7’s clean, articulate sound signature complements the smooth, balanced tonality of the MC331. With 5654W tubes, the MC331 adds a warm, organic layer to the already refined sound of the K7, enhancing midrange detail and vocal richness.

The bass is authoritative—weightier, textured, and slightly more rounded than my Xduoo MH-02 with stock Chinese 6J1 tubes. It’s not boomy or exaggerated but instead delivers tight, musical low-end performance that fills the room with warmth and body.

The midrange is where the combo truly shines. It’s lush, organic, and slightly romantic. Vocals are creamy and emotional, making acoustic tracks feel intimate and captivating. Instruments like guitars and pianos come through with natural timbre, a hallmark of AKM DACs when implemented well.

The highs are smooth and well-extended, offering airy detail without harshness. Cymbals and strings have a refined sparkle that avoids sibilance, making long listening sessions fatigue-free.






Gaming Performance

When it comes to gaming, the Fosi Audio K7 is in its elements. I tested it as a gaming DAC/amp by pairing it with my Meta Quest 2 VR goggles over Bluetooth using the aptX LL codec, alongside the 7Hz Elua IEMs. The low-latency connection was flawless, delivering near-zero lag even during the most intense, fast-paced gaming moments. For my test, I dove into Iron Rebellion VR, a mech combat simulator that demands both precision and immersion—and the K7 didn’t disappoint.

The experience was nothing short of jaw-dropping. The AKM DAC chip’s incredible detail retrieval and holographic spatial sound brought the game to life in a way that felt cinematic. The weighty thuds of my mech’s footsteps felt impactful, the explosions were deep and earth-shaking ( thanks to the deep rumbly subbass of the 7hx elua) and the metallic clangs of battle echoed with realism. The K7’s imaging is so precise that I could pinpoint the trajectory of incoming missiles with remarkable accuracy, giving me a distinct competitive advantage.

It’s not just the clarity and precision that impressed me, though—it’s how immersive everything sounded. The soundstage felt vast and three-dimensional, enveloping me in the game’s environment. The details were so vivid that I could hear subtle cues, like the faint whirring of a distant mech preparing to engage or the subtle hiss of hydraulics under strain. These nuances added a new layer of depth to the gaming experience, making it not just fun but downright exhilarating.



I’ve included a gameplay video from my testing session with the K7. Turn up the volume, and you’ll get a taste of just how intense and immersive the experience is—especially during those frantic combat moments. You can hear every ping, crash, and explosion with crystal clarity, showcasing just how well the K7 handles the chaos of battle.

The K7 proved itself as more than just a capable gaming DAC/amp—it’s an immersive powerhouse that enhances both the emotional and competitive aspects of gaming. If you’re into fast-paced shooters or atmospheric RPGs, it’s a device that brings every detail to life.



Final Thoughts

The Fosi Audio K7 punches well above its weight, offering versatile functionality, excellent sound quality, and gamer-friendly features at an affordable price. Its warm, detailed sound signature makes it a standout for music lovers, while its immersive imaging and usb type c or aptX LL Bluetooth performance make it a perfect companion for gaming.

For a DAC/amp that balances audiophile-grade sound with excellent gaming performance, the Fosi Audio K7 is hard to beat. It’s an intuitive, polished device that will enhance both your listening and gaming sessions.

Link: https://www.kickstarter.com/projects/fosiaudio/fosi-audio-k7-gaming-headphone-amp-dac