Joqueval

Created by a human.
Translated with the help of AI.

The Phantom Menace

If you are a regular player of action games, chances are that more than once you have lasted less than a heartbeat in a match, wondering how it was possible when you hadn't detected anyone nearby.

Perhaps the problem wasn't your reflexes. Perhaps you simply didn't hear them.

With the C3, you can become a phantom menace to your rivals, who will have to change their strategy when playing against you from now on.

Because with the C3, Fosi Audio takes another step forward in the gaming sector.

Following the successful K5 and K7 gaming DACs, the C3 goes one step beyond traditional audio and introduces artificial intelligence applied to signal processing, giving you an additional advantage in first-person action games.

This explosive combination of sound quality and signal processing is the result of the company's R&D in the gaming field and, once again, responds to a specific user demand that Fosi Audio has turned into a product.

And this is where we find an important difference compared with the design philosophy of previous Fosi Audio products.
With the C3, the priority is focused on gaming functionality and on tools that can provide a competitive advantage, without forgetting the sound quality that characterizes the brand.

And when it comes to these features, software takes center stage, complementing the physical controls on the C3 itself.
Fosi Audio has developed a carefully designed control panel that allows us to configure the operating mode, select different profiles and adjust the sound directly from a web browser, without the need to install a dedicated application. The C3 can also be used with PCs and different gaming platforms, turning it into a genuine control center for our audio system.

PEQ control panel:
Fosi Audio C3 PEQ Control Panel
https://cc.fosiaudio.com

Combined with the physical controls and noise cancellation, this can completely change our level of immersion in the game.
StepSense: The Ace Up Its Sleeve
And this is where StepSense comes in, our ace up the sleeve for gaining an advantage over our rivals.

But what exactly is StepSense?

The idea sounds simple on paper and, at the same time, tremendously ambitious: allowing us to hear what would normally get lost in the sonic chaos of a game.

Gunfire, explosions, vehicles, music, environmental effects...
Everything is competing for our attention.

And right in the middle of that chaos, there is one sound that can decide a match:
The footsteps of our enemy.
Fosi Audio has developed StepSense to identify these types of signals in real time and enhance them in relation to the rest of the content.

The system can increase the presence of footsteps by between 3 and 9 dB, while leaving sounds such as gunfire and explosions essentially unchanged.
The stated latency is just 10 ms.

But what is really interesting is that this isn't simply about
increasing the volume, because we could do that ourselves with an equalizer.
The difference is that StepSense uses AI to recognize what we are hearing.

The algorithm has been trained using a large amount of audio data from FPS games and operates locally on the C3 itself, without consuming computer resources.
This allows the processing to act dynamically on the signal while we play.

And this is where the concept becomes particularly interesting, because we are not talking about a simple EQ preset.
We are talking about a system capable of analyzing the signal content and identifying those sonic events that can provide tactical information to the player.

One footstep.
Another footstep.
A reload...
A movement happening outside our field of vision.

These are small fragments of acoustic information that our brain normally has to locate within a genuine storm of sounds.
StepSense does that work for us.

And that small difference can be huge when there are only a few tenths of a second between hearing a footstep and reacting to it.
But the C3 Is More Than Just StepSense
This is where the C3 starts to move away from the image we might initially have of a gaming sound card.
Because behind all this technology, we find a fairly serious audio architecture.

Fosi Audio has built the C3 around an XMOS XU316, a Cirrus Logic CS43131 DAC and a dual headphone amplification stage based on TI TPA6120A2 chips, delivering 320 mW + 320 mW at 32 Ω.

Power and control are handled through a single USB-C connection.
This allows the C3 to drive most gaming headphones and IEMs from 16 to 300 Ω.

The device supports PCM up to 32-bit/384 kHz and DSD256 via USB 2.0, while also incorporating optical and coaxial inputs and RCA outputs.

All of this is housed in Fosi Audio's familiar aluminum chassis, which is more compact this time around, measuring just 95 × 95 × 40 mm, with a front panel tilted by 5°, making it easy to transport our setup between different environments.
This gives us an explosive combination.

On one side, we have artificial intelligence, footstep detection, gaming profiles and DSP processing.
On the other, a digital and analog architecture that could perfectly belong to a piece of equipment designed for conventional audio.
For physical control of the C3, we have two linear slide faders for headphone and microphone level control.
These are accompanied by four buttons with LED indicators, allowing us to:

• Turn the C3 on/off
• Mute the microphone
• Select UAC mode (1/2)
• Select FPS/7.1 mode, switching between gaming mode and simulated 7.1 surround

Because when we finish playing, we can disable the processing, put our weapons away until the next battle and simply use it as a peaceful DAC, headphone amplifier or preamp for our audio system.

Because ultimately, behind the gamer, there is still an audio enthusiast.

And perhaps that is the C3's real phantom menace:

When you think you've simply bought a gaming device, only to discover that you've also bought a DAC.

Created by a human.
Translated with the help of AI.

Fosi Audio PSU20

The Power of Silence

In every discipline, there are small details capable of making the difference between a good result and an outstanding one.
In sports, this concept is known as marginal gains: small individual improvements that, when combined, produce a performance far greater than expected. Fine-tuning the suspension of a racing car, adjusting the tire pressure of a bicycle, properly tuning a guitar, or carefully positioning a pair of loudspeakers can completely transform the overall experience.
High-fidelity audio works in exactly the same way.
Once a system reaches a certain level of performance, dramatic improvements give way to subtle refinements. None of them changes the system on its own, but together they allow it to perform at its absolute best.
The Fosi Audio PSU20 belongs precisely to this category of products.
It doesn't include a new DAC, it doesn't increase amplifier power, nor does it alter the frequency response of your system. Its sole purpose is something that appears deceptively simple: delivering an exceptionally clean and stable power supply.
And that's precisely where its value lies. A high-quality linear power supply is not defined solely by its transformer, but by the engineering behind it and the quality of every component used throughout the design.
I've tested several standalone linear power supplies featuring toroidal transformers and premium components, yet none of them delivered the same sonic results as the PSU20.
________________________________________
The PSU20 is a linear power supply designed to integrate seamlessly into virtually any home audio system.
Unlike conventional switching power supplies, it features an 80 W copper toroidal transformer, an oversized rectification stage, Nippon Chemi-Con capacitors, and independent LM1085 linear regulators for each output.
The result is an exceptionally stable power supply with a specified ripple of only 0.1 mV, significantly lower than that of most conventional switching adapters.
Its outputs allow multiple devices to be powered simultaneously:
• Two selectable DC outputs
o Output 1: 5 V / 12 V
o Output 2: 12 V / 15 V
• One 5 V / 1 A USB output
• Independent protection for each output
It's also worth remembering that components such as DACs, headphone amplifiers, streamers and CD players consume relatively little power, meaning the PSU20 offers two to three times the power actually required, ensuring effortless operation under any normal listening conditions.
________________________________________
The first impression when taking the PSU20 out of the box is that this is something very different from the typical wall-wart power adapter.
Its fully metal enclosure immediately conveys a premium feel, perfectly matching the build quality found across the rest of the Fosi Audio range.
Measuring 155 × 185 × 75 mm and weighing approximately 2.7 kg, it quickly becomes obvious that much of the internal volume is occupied by the large toroidal transformer.
The design follows Fosi Audio's clean and minimalist aesthetic. The front panel remains uncluttered, featuring only the illuminated output indicators and a discreet company logo.
The rear panel includes:
• IEC mains power input
• Two selectable DC outputs
• 5 V USB output
• Output voltage selector
Overall, the PSU20 feels like a product designed to provide many years of reliable service.
________________________________________
The package contents are simple but complete:
• PSU20 linear power supply
• 1.2 m DC cable
• 0.3 m DC cable
• IEC AC power cable
The supplied cable lengths make integration easy whether the PSU20 is placed on a desktop, inside a Hi-Fi rack, or hidden from view—although, given its design and build quality, it deserves to be proudly displayed.
________________________________________
Although externally it may appear to be a fairly simple device, the internal engineering is considerably more sophisticated.
The power path follows this sequence:
230 VAC
↓
80 W Copper Toroidal Transformer
↓
High-current bridge rectifier
↓
Nippon Chemi-Con capacitor bank
↓
Independent LM1085 linear voltage regulation
↓
DC outputs with a specified ripple of just 0.1 mV
This design minimizes electrical noise while maintaining exceptionally stable voltage, even when several connected devices demand current simultaneously.
________________________________________
Unlike conventional switching power supplies, the PSU20 relies on a linear architecture built around its 80 W toroidal transformer. This design prioritizes electrical stability and extremely low noise rather than maximum power efficiency.
Throughout my testing powering the Fosi Audio ZH3, Fosi Audio GR70, and Fosi Merak CD Player, the PSU20 operated flawlessly without any instability.
The Fosi Audio i5 planar magnetic headphones, which already deliver outstanding resolution, revealed an additional level of detail and refinement when powered through this setup.
As expected from a linear power supply, the enclosure becomes noticeably warm after several hours of continuous operation. In my listening room, however, the external temperature never exceeded 32°C, although the chassis does become pleasantly warm to the touch.
This is neither excessive nor concerning; it simply reflects the normal heat dissipation associated with linear power supply designs.
Should the internal temperature exceed approximately 55°C, an integrated cooling fan automatically activates to maintain safe operating temperatures, even when multiple devices are being powered continuously.
During all my listening sessions, the fan never activated.
According to Fosi Audio, even when operating it produces only 30 dB of noise, making it effectively inaudible from the listening position and therefore completely suitable for Hi-Fi environments.
Altogether, the PSU20 inspires confidence. Its metal enclosure, generously sized transformer and intelligent thermal management allow it to operate continuously without overheating or any noticeable loss of performance.
________________________________________
For this review, the PSU20 was evaluated in the following system:
• Fosi Audio ZH3
• Fosi Audio i5 planar magnetic headphones
• M-Audio BX8 D3 active studio monitors
• Various high-resolution recordings
The comparison consisted of evaluating the ZH3 using its original switching power adapter versus the PSU20.
The PSU20 does not change the sonic character of either the DAC or the headphone amplifier—which is exactly as expected.
However, several subtle improvements became noticeable:
• Slightly quieter background
• Cleaner presentation during complex musical passages
• Better-controlled and deeper bass
• Improved instrument separation
• Slightly more stable soundstage
These are naturally subtle improvements resulting from cleaner power delivery, and their audibility will depend largely on the overall resolution of the audio system.
That said, I found the differences to be noticeable even on relatively modest setups.
________________________________________
A Cleaner Audio Ecosystem
One of the PSU20's biggest strengths is its ability to replace several independent power adapters.
A typical desktop audio system may include:
• DAC
• Headphone amplifier
• Streamer
• Preamplifier
Each device usually comes with its own switching adapter, creating unnecessary cable clutter.
The PSU20 centralizes much of that power delivery, reducing the number of power bricks connected to the mains while creating a cleaner, tidier and more elegant installation.
________________________________________
If you own only a single DAC or headphone amplifier, you may initially feel that the improvement alone doesn't justify the investment.
However, as your system grows, the PSU20 increasingly becomes the central power hub for your setup.
Its advantages are clear:
• Fewer cables
• Fewer power adapters
• Centralized power delivery
• Reduced electrical noise
• Outstanding build quality
• Efficient thermal management
• Plenty of power for future system expansion
Rather than being just another accessory, the PSU20 is a long-term investment for anyone looking to build a cleaner, better-organized and technically optimized Hi-Fi system.
________________________________________
The Fosi Audio PSU20 doesn't attempt to reinvent your audio system or deliver dramatic sonic transformations.
Its objective is far more sensible: to provide exceptionally clean, stable and carefully engineered power, allowing every connected component to perform at its full potential.
Its excellent build quality, generously sized toroidal transformer, premium internal components and intelligent, whisper-quiet active cooling system make it particularly appealing for enthusiasts running several source components in the same setup.
The sonic improvements are subtle—as expected from a power supply—but the combination of practical benefits, engineering quality and long-term usability becomes evident from day one.
If I had to compare it with another field, I would say the PSU20 is the equivalent of ordering the performance package on a sports car. It doesn't fundamentally change the vehicle itself, but it refines countless small aspects that together create a noticeably more rewarding driving experience.
Likewise, the PSU20 isn't about spectacular changes—it's for listeners who understand that a truly great Hi-Fi system is also built on something we rarely see: the quality of the power feeding every component.

Translation produced with the help of AI

MERAK – Great Music Doesn’t Care About Formats

Year 2026. After decades of digital dominance, versions are beginning to resurface that the general public has never heard—magnificent recordings laser-etched onto discs that younger generations barely recognize.

Although the CD emerged in the early 1980s, it surpassed vinyl and cassette sales in less than a decade. But like all reigns, it wasn’t eternal. In the early 2000s, digital files began to take over, leaving the three major physical formats virtually extinct.

And yet, human nature doesn’t always seek perfection. There is a constant desire for that “something special” that brings emotion and soul to the experience.

Instant access and unlimited music are undeniably convenient, but they also introduce a certain disconnect in the listening experience. The specialized record stores are gone—the ones where someone would personally recommend a new release each week, often surprising you.

And this is where Merak comes in—Fosi Audio’s answer to enjoying music in a physical format, specifically CD.

Physical or digital?

In reality, both. A digital format with a physical dimension that brings it closer to the listener.

Listening to your favorite artist on a recording that, in many cases, is not the same version found on streaming services or radio playlists carries real weight. Add to that the ritual—opening the booklet, observing the artwork, dedicating time to listening… all of it transforms the experience compared to passive, sequential playback.

Merak allows us to rediscover CD collections that may have lost their place due to space constraints. It also opens the door to new releases that artists are once again issuing in physical format.

This is not a trend-driven product, but a CD player adapted to modern times—without compromising on sound quality.

The Merak is a compact CD player (150 × 150 × 28 mm), only slightly larger than a standard CD case. Its size makes it easy to transport or integrate into a home audio system with minimal footprint.

This time, Fosi Audio opts for a light metallic gray finish, moving away from the traditional black. A design direction already seen in the S3 streamer, breaking away from the usual austerity of audio sources.

This shift can be seen as a statement of intent: products with their own identity that, while aimed at the Hi-Fi market, fit naturally into any environment without requiring expertise.

For purists, however, there are already requests for black versions to maintain visual consistency with other components.

In terms of build quality, the Merak features a well-constructed plastic chassis with solid assembly and a fully featured front and rear panel. While CNC aluminum is absent, the overall finish remains in line with expectations.

The CD is loaded from the top via a transparent lid, allowing you to see the disc in motion—adding a distinctive visual element.

The Merak offers two clearly differentiated use modes: portable and desktop.

It includes a compact remote control, but its size encourages direct interaction through its physical controls.

On the front panel, six buttons handle power, output selection, playback, and REC functions, alongside an OLED display and a 3.5 mm headphone output.

This output is powered by a TPA6120, a well-known headphone amplifier design, delivering 210 mW x2 @ 32 Ω—more than sufficient for earphones like the IM4.

In portable mode, only a power source is required. Volume is adjusted via a side-mounted slider with an elegant orange accent.

There is no internal battery, allowing the device to be powered by any 5V/2A source or power bank. Power consumption is extremely low (1W during CD playback), resulting in excellent runtime. Additionally, the absence of a battery reduces weight and eliminates long-term degradation—an intelligent design choice.

In desktop mode, the Merak reveals its more audiophile-oriented side.

It includes:

Line output (3.5 mm)
USB port (read/write)
Optical SPDIF output
12V trigger output

It also features ESP (Electronic Skip Protection) to prevent interruptions during movement.

The integrated DAC is a Cirrus Logic CS43131, delivering performance well above what is typically found in this category:

Signal-to-noise ratio: 124 dB
THD+N: 0.0009%
Dynamic range: 124 dB

But the Merak goes beyond being just a CD player.

It can also function as a digital transport, feeding an external DAC and allowing users to rediscover nuances in CDs they thought they already knew.

Supported formats:

CD: CDDA, CD-R, CD-RW
CD-R files: FLAC, WAV, WMA, AAC, MP3
SACD: CD layer only

Because even at 44.1 kHz / 16-bit, there are true gems that haven’t been subjected to streaming compression. A great recording is not defined by numbers alone, but by the sum of its elements.

Additionally, it includes a particularly useful feature: USB recording.

It allows direct copying of tracks or entire discs to a USB drive (up to 128 GB) at 1X speed—even during playback.

USB playback formats:
MP3, WAV, FLAC, AAC, APE, WMA

This makes it easy to create custom compilations quickly and efficiently.

In transport mode, when paired with a DAC such as the ZH3 or the S3 streamer via optical output, the Merak truly shines.

The digital signal is transmitted without limitation, allowing every detail of the recording to be revealed.

With a simple press, users can select the source (CD/USB) and output type (line out, optical, or headphones), demonstrating its flexibility and adaptability to different setups.

Conclusion

The Merak is a source worth serious consideration.

For nostalgic listeners looking to rediscover their CD collections.
And for a new generation beginning to realize that music… was never just about the format.

Sometimes, what you’ve been searching for your whole life…
has been right there beside you all along.

Fosi Audio S3

The Hi-Fi Streamer

Can a relatively compact streamer become the brain of a complete Hi-Fi system? Over the past three months I’ve been testing the Fosi Audio S3 to find out.
During this time I’ve been using a beta unit, testing it with the iOS and Android apps, integrating it within the Roon ecosystem, and trying it with different streaming services and amplifier configurations.
This extended real-world use makes it possible to evaluate not only its sound quality, but also some of the most important aspects of a modern streamer: stability, ease of use, and how well it integrates into an existing Hi-Fi system.

Design and Concept

The Fosi Audio S3 is the company’s network streamer, designed to act as a bridge between modern streaming services and traditional Hi-Fi systems.
However, it’s more than just a streamer. The device integrates three main functions:
• Network streamer
• Internal DAC
• Digital preamplifier functions
This combination allows the S3 to work either as a digital source in an existing system or as the central hub of a minimal Hi-Fi setup.
The internal DAC is based on the well-known AKM AK4493S, a chip appreciated in the Hi-Fi world for its balanced, detailed, and natural presentation.
One distinctive design element of the first production units is the dark grey finish, which gives the S3 a unique visual identity.
It integrates very well both as a standalone component or stacked with other Fosi devices.
Fosi has confirmed that future versions will also be available in classic black, although the grey finish already pairs nicely with devices such as the ZD3 or ZH3.

Connectivity

One of the most interesting aspects of the S3 is its very versatile connectivity, making it adaptable to many different system configurations.
Inputs
• Wi-Fi 6
• Ethernet
• Bluetooth 5.3
• Optical input
• RCA analog input
• HDMI eARC with CEC
This allows the S3 to either integrate into an existing system or become the central control hub of a completely new setup, easily accessible to everyone in the household.
Outputs
• Balanced XLR
• RCA
• Optical digital output
• Subwoofer output
• Trigger out for synchronized power control
Thanks to this wide range of connections, the S3 can be used in multiple ways:
• as a streamer feeding an external DAC
• as a DAC/preamp connected directly to a power amplifier
• as a digital hub for active speakers
• or as part of a traditional stereo system
In addition to app control, the S3 also includes a Bluetooth remote control, allowing operation without needing line-of-sight with the device.

Using the S3 as a Streamer or Digital Transport
One of the strengths of the S3 is its flexibility within a system.
It can operate either as a complete streaming source using its internal DAC or as a digital transport feeding an external DAC.
Full streamer mode
When using the XLR or RCA outputs, the S3 performs digital-to-analog conversion using its internal AK4493S DAC.
It also includes an RCA analog input, which allows additional sources to be connected, such as a turntable with phono preamp or another analog device.

Digital transport mode
For users who already own a dedicated DAC, the S3 can also be used simply as a streaming transport.
In this setup, the digital signal is sent through the optical output to the external DAC, which performs the conversion.
This makes it easy to integrate the S3 into existing Hi-Fi systems that only need streaming capability.

Resolution and Audio Support
Depending on the connection used, the S3 supports different audio resolutions.
Analog outputs (internal DAC)
up to 32-bit / 768 kHz PCM
Optical digital output
up to 24-bit / 192 kHz

Network streaming
resolution depends on the streaming service and quality settings.

Streaming Service Compatibility
The S3 supports many of the most widely used streaming platforms today, with additional services expected in the future.
Current compatibility includes:
• Roon Ready
• Tidal Connect
• Spotify Connect
• AirPlay 2
• Google Cast
This allows music to be streamed directly from the official service apps, without relying on a separate control interface.
In practice, this means anyone in the household can use the system without needing technical knowledge.

App and Control Experience
Ease of use is one of the most important aspects of any modern streamer, and here the S3 clearly prioritizes simplicity.
The app focuses on straightforward device management.
In everyday use, the process is very simple: just open the streaming app you normally use and select the S3 as the playback device.
This avoids complicated interfaces and allows users to continue using familiar apps such as:
• Tidal
• Spotify
Other services can also be used through AirPlay or Google Cast, making it easy to integrate the S3 within a wider smart-home ecosystem.
The app also includes a 5-band equalizer, allowing small tonal adjustments to better match the system or personal listening preferences.
It’s not meant to replace a full DSP solution, but it’s a useful tool for quick tonal adjustments when needed.

Real-World Use
During the testing period I used the S3 with:
• Tidal
• Spotify
• control from iOS devices
• control from Android devices
• phones and tablets
Overall system stability has been excellent.
The device works reliably both via Wi-Fi and Ethernet, and playback remained stable throughout the testing period.
One particularly useful feature is that two devices can control the S3 simultaneously, which is very convenient in a shared household.

Roon Integration
One of the aspects I was most interested in testing was its integration with Roon.
After enabling developer device access, the S3 worked correctly as a Roon endpoint within the ecosystem.
This allows users to benefit from:
• full library management
• multi-room playback
• integration with other digital sources
For users already invested in Roon, the S3 fits very naturally into the system.

Sound Quality
The AK4493S DAC delivers a very balanced sound presentation.
During testing, the S3 consistently sounded:
• clean
• transparent
• detailed
• with a well-organized soundstage
It doesn’t attempt to add coloration, which makes it a very good foundation for modern streaming-focused Hi-Fi systems.
The balanced XLR outputs also make it easy to integrate the S3 into more advanced setups or systems using dedicated power amplifiers.

Impressions After 3 Months
After several months of use in different setups, the overall impression is that the S3 is a very solid and well-thought-out device for daily use.
Stability is one of the most important aspects of a streamer, and throughout the testing period the S3 performed flawlessly both over Wi-Fi and Ethernet, streaming continuously from services such as Tidal and Spotify.
Control from iOS and Android devices was also very smooth, and the ability for two devices to control the streamer at the same time is a small but very practical feature in everyday use.

Who Is the Fosi Audio S3 For?
The S3 can be particularly appealing for:
• users entering the Hi-Fi streaming world
• those looking to simplify their audio system
• users who already own a DAC and need a dedicated streaming transport
• Roon users looking for a network endpoint
Its versatility allows it to fit equally well in compact setups or more advanced systems.

After several months of testing, the Fosi Audio S3 proves to be a very capable and versatile streamer.
Its combination of:

• extensive connectivity
• a capable internal DAC
• support for major streaming services
• Roon integration
• simple everyday operation
makes it a very interesting solution for integrating modern streaming into a Hi-Fi system.

The philosophy behind the S3 seems clear: to offer a flexible, easy-to-use device capable of becoming the digital heart of a modern audio system.

New high-level DAC with very interesting features

Fosi Audio MD3

https://www.kickstarter.com/projects/fosiaudio/fosi-audio-md3-headphone-dac-amp-dongle-with-rear-display/description

Fosi Audio MD3: A Bridge Between Mobility and High Fidelity

There is an idea that has echoed through the Hi-Fi world for decades:

The source matters.

A great amplifier cannot compensate for a poor signal.
Outstanding headphones cannot reveal what they never receive.
In traditional systems, we understand this instinctively: digital transport, dedicated DAC, amplification, and finally the transducer.
Yet in the mobile world we tend to simplify everything… until we discover that a smartphone can actually become an excellent digital transport.

That is precisely where the MD3 finds its true purpose within the ecosystem.

The Smartphone as a Digital Transport
Using an iPhone or an Android device as a source does not mean listening to “phone audio.”

It means using the phone as a digital transport.
The signal leaves the phone in the digital domain, bypassing the internal DAC entirely. From that moment on, the MD3 assumes the critical task: converting that information into analog signal with greater precision and stability.

Inside, we find the ESS ES9039Q2M DAC — a chip capable of genuine resolution and wide dynamic range — paired with four ESS ES9603Q amplifier stages, delivering a clean and controlled output capable of driving most modern IEMs with ease.

The logic is exactly the same as in a traditional Hi-Fi system:

Transport → DAC → Amplification → Headphones

When connecting an iPhone to the MD3, the change is not perceived simply as an increase in volume.

Something else emerges instead: greater clarity, improved instrument separation, tighter bass definition, and a more organized soundstage.

The available power is more than sufficient for a device of this size:
• 3.5 mm: ≥ 80 mW ×2 @ 32 Ω
• 4.4 mm balanced: ≥ 180 mW ×2 @ 32 Ω
• Signal-to-Noise Ratio: ≥ 115 dB
• Frequency Response: 20 Hz – 48 kHz (±0.2 dB)
• Volume Control: 100 steps

Clearly, this is not a desktop device. Yet the available output power allows you to enjoy high-quality music virtually anywhere.
The stepped volume control is particularly valuable with sensitive IEMs, allowing precise adjustment without abrupt jumps.
In this context, the MagSafe-compatible magnetic attachment, using sixteen N52 magnets, provides a very welcome sense of physical coherence. The setup remains aligned and stable, avoiding unnecessary stress on the connector.
The result is a compact portable system that feels unified and purposeful.

To accommodate different setups, the kit also includes short USB-C bridge cables as well as an adapter.
The MD3 also allows switching between UAC 1.0 and UAC 2.0, and offers several digital filters to fine-tune the sonic presentation.
The phone stops being a limitation.
Instead, it becomes what it truly is:
a small, serious digital transport… with character.

Build and Presence

The MD3 surprises the moment you hold it.
Its CNC-machined aluminum chassis conveys rigidity and precision. There are no gaps, no sense of lightweight accessory build. At just 50 grams, its structural density has clearly been carefully engineered.
Aluminum is not just an aesthetic choice. It also provides mechanical stability and effective heat dissipation in such a compact form factor.
The MD3 is available in anodized silver or anodized black, both paired with orange leather accents — a bold visual detail that introduces personality without sacrificing elegance.
Small, yes.

Clearly serious… but also playful.

One of its most distinctive elements is the front display.
It includes animations, dynamic emojis, and even the possibility of turning the screen into a small personal canvas: album artwork, photographs, or artistic images.

This does not affect the sound, but it does change the way we interact with the device.
On a modern desk — where phone, laptop, and tablet coexist — the device stops being invisible and becomes part of the creative environment.

Fit and Personalization: When the Listener Becomes Part of the System

When pairing IEMs such as the Fosi Audio IM4, fit becomes an essential part of the final result.
In fine-tuning the listening experience, we ourselves become part of the system.
The selection of silicone tips allows adjustments in several aspects of the sound:

• Insertion depth
• Passive isolation
• Bass response
• Spatial perception

A better seal provides deeper low-frequency extension.

A shallower insertion can expand the soundstage and alter the perception of air.

At that point, the ecosystem is no longer purely electronic — it becomes physical as well.

With closed-back dynamic headphones, the response is often more immediate and straightforward.

With IEMs, however, fit can genuinely transform the listening experience.

The MD3 does not impose a sonic signature.

Instead, it supports and reveals the character of each headphone.
And it is also worth remembering that it can integrate into a desktop system as a dedicated digital source, demonstrating that it is not only portable, but also versatile within a larger setup.

Beyond the Smartphone

Although its primary use is clearly oriented toward mobile devices, the MD3 is not limited to that scenario.

Connected to a laptop or tablet, it allows you to enjoy true Hi-Res audio in many contexts: home desk setups, office environments, travel, or hybrid creative spaces.
It functions as a genuine dedicated DAC, bypassing the generic internal circuitry of many devices and noticeably elevating the overall sonic performance.

Of course, this is the portable entry within the brand’s ecosystem. It does not offer the broader connectivity or more advanced architecture found in larger models such as the Fosi Audio ZD3 or Fosi Audio ZH3, which are designed for more complete and stable configurations.

But that is precisely its strength.

It does not try to replace them.
Instead, it brings the same philosophy into a compact, lightweight, and adaptable form factor.

And it is precisely in that balance between mobility and technical coherence that the MD3 finds its true identity.

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