Fosi Audio

The Fosi Audio ZD3 Delivers Refined DAC Performance With Effortless Usability, Offering Superior Audio Quality Tailored For Pure Listening Enjoyment

• Fully balanced flagship desktop DAC preamp
• Built with high-performance ESS ES9039Q2M chip
• Swappable op-amp design
• Offers comprehensive connectivity options
• Lossless wireless streaming

Flagship Chipset

The ZD3 is an audiophile-grade balanced stereo DAC meticulously developed by Fosi Audio. The XMOS XU316 chip provides precise digital signal processing, paired with the ESS 9039Q2M decoding chip to ensure ultimate audio detail and precision.

The Qualcomm QCC 3031 chip enhances connectivity and signal stability, while the LME49720 operational amplifier greatly improves audio clarity and dynamic range. Whether for music or movies, it delivers an immersive high-fidelity audio experience to users.

Balanced Circuit Design

The fully discrete balanced circuit design effectively reduces electronic noise and signal crosstalk, ensuring pure and clear audio output. Professional-grade balanced XLR output support further enhances signal stability and audio fidelity, making it suitable for demanding audio applications.

Multiple Inputs + Outputs

The ZD3 supports USB, HDMI (ARC), coaxial, optical, and Bluetooth inputs, easily accommodating both traditional and modern digital sources. It also offers RCA and XLR outputs, making it an ideal choice for connecting a variety of audio equipment, providing exceptional flexibility and broad applicability.

Additional Features

Swappable Op-Amp Design
Easily replaceable DIP8 dual discrete op-amps, meeting your pursuit of a personalized audio experience, such as LME49720, NE5532, MUSES02, SS3602.

Bypass Mode
The signal bypasses the internal preamp section, providing a fixed output level for direct signal transmission.

Trigger In/Out
Enables synchronized on/off across your audio setup, automating system control for seamless operation.

Front Panel OLED Display
Offers clear visibility, allowing users to easily monitor device status and settings in real-time.

Specifications

• Chipset: XMOS XU316 + ESS 9039Q2M + QCC3031 + LME49720
• Max Sampling Rate
  • USB: PCM 32bit/768kHz; DSD512
  • OPT/COAX: PCM 24bit/192kHz
  • HDMI: PCM 24bit/192kHz
  • Bluetooth: PCM 24bit/48kHz
• Output Level: XLR 5Vrms, RCA 2.5Vrms
• Inputs: USB, HDMI (ARC), Coaxial, Optical, Bluetooth, USB
• Outputs: XLR, RCA
• SNR: 126dB
• THD+N: <0.00008%
• Dynamic Range: 126dB
• Noise Floor: ≤2μV
• Frequency Response: 20Hz-20kHz (±0.1dB)
• Bluetooth
  • Version: 5.0
  • Connection Distance: ≥13m
  • Formats: SBC, AAC, APTX, APTX HD
    
• Input Voltage and Current: DC 12B 1.5A
• USB Compatible Devices: Windows 7, 8, 8.1, 10, 11, Mac OS X, Linux (some require drivers)

In the Box

• Fosi Audio ZD3 DAC
• 12V power adapter
• Infrared remote control
• USB-A to USB-B cable
• 3.5mm trigger cable
• User manual

The Fosi Audio SK01 is a Powerful Headphone Amp, a Customizable Analog Preamp, and An Accurate Equalizer, All-in-One Portable Device

• Integrated treble, middle, and bass controls with midpoint positioning
• Abundant interfaces and adjustments for personalized sound output
• Caters to both desktop and portable music listening
• Up to 6 hours of continuous usage with built-in high-capacity battery

Tailor-Made Audio Experience

The Fosi Audio SK01 is a versatile headphone amplifier designed for both desktop and portable setups, offering powerful amplification and precise tone shaping. With its tri-band EQ for treble, mids, and bass, you can tailor your sound to suit your personal preferences.

Whether used as a high-performance headphone amp, an adjustable analog preamp, or a detailed equalizer, the SK01 enhances your listening experience with refined sound and customizable character.

As a headphone amp, it enhances your listening with added depth and clarity. As a preamp, it delivers clean, powerful signal amplification. And as an equalizer, it fine-tunes your sound with precise control, revealing the full detail of every instrument.

Unmatched Headphone Compatibility

Unlock powerful performance and flexible connectivity with the Fosi Audio SK01. Featuring a 3.5mm line-in, 3.5mm line-out, and a combined 3.5mm/6.35mm headphone output, the SK01 adapts to your setup with ease. With up to 2400mW RMS output at 32Ω and support for headphone impedances ranging from 16–300Ω, it delivers dynamic, high-quality sound in a compact and portable form, perfect for elevating any listening environment.

Additional Features

Long-Lasting Battery
Enjoy up to 6 hours of continuous usage with the built-in high-capacity battery, while the isolated power design rejects interference, providing a pure listening experience without any interruptions.

Exquisite Design
Crafted with an aluminum alloy body, the SK01 is both elegant in appearance and touch, adding a touch of sophistication to your desktop setup.

Tri-Band Control
With independent treble, midrange, and bass controls—plus central detents for tone bypass—dialing in the perfect balance is effortless. In high-impedance mode, the SK01 delivers up to 2400mW of powerful output.

Diverse Capabilities
Quickly restore the original sound with a single press of the tone-defeat button. Enjoy immersive late-night listening with the loudness function, and fine-tune output for different headphones using the adjustable gain switch.

Specifications

• Input: 3.5mm line-in
• Output: 3.5mm headphone, 6.35mm headphone, 3.5mm line-out
• Amp Output Max. Power
  • High Gain: RMS 2400mw/ 32Ω
  • Low Gain: RMS 300mw/32Ω
• Frequency Range: 20Hz-20kHz (±0.5dB)
  
• THD+N: 0.001% @ 1kHz and 770mV
  
• SNR: ≥108dB
  
• Headphone Matching Impedance: 16-300Ω
  
• Dimensions: 4.76" x 2" x 1.69"
  
• Weight: 0.641b
• Power Supply: 5V, USB Type-C

In the Box

• Fosi Audio SK01 Amplifier and preamp
• USB-A/C to USB-C cable
• User manual

Fosi Audio Presents the MC351, An Innovative Power Amplifier That Combines High-Performance Decoding and Amplification to Meet a Wide Range of Needs

• All-in-one DAC Amplifier
• (2x) TPA3255 Texas Instruments amp chips
• Supports 2.1 system configuration with passive subwoofer and pre-out outputs
• Dual 4700μF capacitors for enhanced sound quality
• Ideal for home theatre and HiFi listening

2.1 Channel Integrated Amplifier

The Fosi Audio MC351 is a high-performance integrated amplifier with a built-in DAC and support for Bluetooth, USB, optical, and coaxial digital inputs. Its versatile connectivity and outputs for passive subwoofer and pre-out make it ideal for configuring a 2.1 system or stereo Hi-Fi setup. A circular VU meter adds vintage charm, combining retro visuals with rich, detailed sound for a complete listening experience.

Dual Amp Chips for High Power Output

Equipped with two high-end Texas Instruments TPA3255 Class-D amplifier chips and a 100-fin heatsink, the MC351 can stably output up to 165W x 2 + 350W power in a 2.1 channel setup. The dual PCBA separated design ensures that the input and output signals do not interfere with each other, providing you with the purest and most impeccable sound quality.

User-Friendly Control

The MC351 offers one-touch switching between five input modes and intuitive bass and treble controls with center detents for tone bypass. An auto-standby function reduces power consumption by entering standby after two minutes of inactivity. Input settings are saved and automatically restored on restart, making sound customization effortless and efficient.

Exquisite Craftsmanship and Vintage Charm

Crafted from CNC-machined aluminum alloy with a finely sandblasted finish, the MC351 features a seamless, screw-free design that exudes minimalist elegance. A round mini VU meter adds a charming retro touch—its needle dances with the music, enhancing the listening experience with visual flair. Ideal for turntables, the MC351 brings vintage warmth to your favorite classic tracks.

Specifications

• Output Power: 165W x 2 + 350W @ 4Ω
• Terminating Impedance: 4-8Ω
• Input Mode: Bluetooth 5.3, RCA, COA, OPT, and USB
• Output Mode: SPK OUT, SUB OUT, 3.5mm PRE OUT
• Frequency Range: 20Hz - 20KHz(±0.1dB)
• THD: ≤0.03%
• SNR: ≥100dB
• DC Input Range: 24-48V
• Sampling Rate: USB24bit/96kHz ; OPT/COA 32bit/192kHz
• Power Supply: 32V/5A, 48V,5A
• Dimensions: 7.28" x 5" x 2.24"

In the Box

• Fosi Audio MC351 Amplifier
• 32V/5A Power adapter
• User manual

The Fosi MC331 is a Versatile All-in-One DAC/Amp That Blends Warm, Rich Tube Sound With Seamless Source Switching For an Effortless Hi-Fi Experience

• A DAC, tube amplifier, and preamplifier with Bluetooth integration
• Features one analog and four digital input modes for wide compatibility
• VU meter and vacuum tubes add warm sound and a nostalgic feel
• Replaceable tube design for customizable sound signature

All-in-One Design

The MC331 is a 2.0 channel integrated amplifier with vacuum tubes and a built-in DAC. It can play the roles as a DAC, preamp, and amplifier simultaneously in an audio system to meet various needs in one single device. The MC331 supports one analog and four digital input modes, ensuring compatibility with a broad range of audio sources. It also boasts a pre-out port, facilitating easy setup of a 2.1 system.

Vacuum Tubes

As an integrated tube DAC/amp, the MC331 combines modern function with retro charm. The glowing 5654W vacuum tubes and VU meter add a warm, nostalgic aesthetic while also enriching the sound with smooth, analog character. The included 5725W tubes enhance musical warmth and depth and can be easily swapped with other 7-pin tubes to suit your preferences. For added safety, the unit comes with two protective tube covers to prevent accidental burns during operation.

Setup Flexibility

The MC331 features Bluetooth, USB, coaxial, optical, and RCA inputs for broad compatibility with sources like computers, phones, CD players, and turntables with built-in phono preamps. Flexible output options include speaker terminals, a 3.5mm pre-out, and a 3.5mm headphone jack, making it easy to build and customize your ideal audio setup.

Compact, Yet Powerful

The MC331 only takes up minimal desktop space but boasts a maximum power output of 105Wx2@4Ω, effectively driving your bookshelf speakers. Additionally, it has a pre-out and a 3.5mm headphone output, making it versatile enough.

Retro Style, Modern Simplicity

The MC331 adds nostalgic features including the VU meter and the vacuum tubes. The VU meter pointer dances to the rhythm of the music, which shows signal strength in real-time. The replaceable tube design allows you to customize the sound signature to suit your personal preferences.

The MC331 comes with a remote control, allowing you to adjust bass and treble from the comfort of your listening chair. All features can be operated either via the front panel or the remote control, including: power on/off, mute/unmute, play/pause, next/previous track, volume adjustment, input mode selection, Bluetooth pairing reset, and bass/treble controls.

Specifications

• Channel: 2.0
• Input: RCA, Bluetooth, USB, Optical and Coaxial
• Output: Passive Speakers Output, Pre-Out, 3.5mm Headphone Output
• Chipset: TPA3221+FS-2348B-2F (Fosi Audio Silicon)
• SNR: ≥100dB
• Dynamic Range: ≥ 00dB
• THD: ≤0.03%
• Terminal Impedance: 4-8Ω
• Max Output Power: 105W× 2@ Ω
• Frequency Response: 20Hz-20kHz(±1dB)
• Headphone Impedance: 32-300Ω
• Voltage Range: DC 19-24V
• Sampling Rate: USB - PCM16bit/48kHz
• Bluetooth Distance: ≥10m
• Bluetooth Formats: SBC, AAC
• Dimensions: 10" x 2" x 2.7"

In the Box

• Fosi MC331 DAC/Amp
• 24V/4.5A Power adapter
• User manual

The Fosi Audio K7 is Engineered for Precise, Immersive Sound, Perfectly Suited for Both High-Fidelity Music and Next-Level Gaming Experiences

• Gaming/Hi-Fi desktop DAC and amp
• Features powerful audiophile-grade chipset
• AKM AK4493S DAC chip
• Fully balanced circuitry
• Comprehensive digital inputs and versatile outputs

One Device Meeting Multiple Needs

The K7 is designed for audiophiles who love music and gaming. It can serve as a powerful hub for building your desktop audio system. Whether you're enjoying music, gaming, or working, the K7 can handle it all with ease.

With ultra-high resolution and extremely low distortion, it accurately reproduces every detail. The high-power output drives your headphones to their full potential, allowing you to enjoy the purity of music. Compatible with devices such as PC, PS5 Pro, PS5, and Switch, K7 effortlessly achieves precise audio decoding. Features like sound localization and sound effects adjustment help create an immersive gaming experience, making every battle more thrilling.

Audiophile-Grade Chipset

The K7 integrates an audiophile-grade chipset combination including the AK4493S DAC chip, XMOS XU208 audio processing chip, TPA6120 amp chip, and OPA1612 op-amp for high resolution, wide dynamic range, ultra-low noise, low latency, and high output power. The exceptional performance will make both gaming and music listening flawless.

Feature Packed

Hi-Res Bluetooth Codecs
Equipped with the Qualcomm QCC3031 Bluetooth chip, supporting aptX HD, aptx LL, aptX, AAC, and SBC codecs.

User-Friendly and Practical Control Design
The K7 features a 1.5" LCD high definition display for easy viewing. It is integrated with tactile shortcut buttons, multi-functional press-able knobs, and sits at an angled ergonomic design.

Aluminum Alloy Body with CNC Design
A compact and exquisite full-metal chassis with fine sandblasting for a robust and durable design.

Triple Intelligent Protection
The K7 promises uninterrupted gaming and entertainment with built-in overhear protection, overload protection, and overcurrent protection.

Comprehensive Connectivity
Supports USB-C, coaxial, optical, Bluetooth aptX HD/LL, and 3.5mm microphone input. Outputs include 4.4mm BAL, 3.5mm SE, and RCA, easily connecting to headphones, powered speakers or amplifiers for desktop setups.

Fully Balanced Circuitry, 0.0002% Low Distortion
Effectively reduces noise and interference, equipped with gain control and headphone protection circuits to ensure clear, authentic audio output.

Multiple LDO Regulators
Each stage utilizes low-noise LDO regulators for pure power output, enhancing audio performance with robust power support.

Specifications

• Chipset:
  • XMOS XU208
  • AKM4493SEQ
  • QCC 3031
  • TPA6120
• 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
• 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)
• Dimensions: 155mm x 95mm x 55mm
• Weight: 530g

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

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 (±0.1dB)

RCA Output

• Output Level: ≥2Vrms
• SNR: 20Hz-20kHz (±0.1dB)
• THD+N: 0.0005%
• Dynamic Range: 121dB
• Noise Floor: ≤3μV
• Frequency Response: 20Hz-20kHz

In the Box

• Fosi Audio K7
• USB-A/C to USB-C cable
• Bluetooth antenna
• DC 12V power supply
• 3.5mm headphone splitter
• User manual

Fosi Audio Enters the World of IEMs with the IM4, Delivering Rich Musical Detail with an Open-Back Design

• 10mm PU Beryllium-coated diaphragm
• Dual-chamber acoustic design
• Powerful N52 dual-magnet for control and speed
• Includes OFC Silver-plated cable

Fosi's First IEM

The name "IM4" reflects the phrase "I am for," a declaration of support, advocacy, and identity. It is open-ended, inviting participation inside and out in both aesthetics and sound. 

The IM4 features an open-back acoustic design and a 10mm beryllium-coated diaphragm driver, delivering a spacious soundstage and musical detail, a true reflection of Fosi's brand spirit: Hear the Unheard. Their tuning team aimed to create a balanced, relaxed, and versatile listening experience.

High-Fidelity Sound

10mm PU Beryllium-Coated Diaphragm
PU ensures smooth mids and punchy lows, while the beryllium coating adds clarity and sparkle to high frequencies.

N52 Dual-Magnet
A powerful, stable magnetic field improves control and speed, delivering cleaner sound with better dynamics.

Dual-Chamber Acoustic Design
The front chamber's nine-port design ensures balanced frequencies, while the rear chamber extends treble detail. 

OFC Silver-Plated Cable
Braided with 4 strands of 392-core 5N high-purity OFC silver-plated wire, the cable offers excellent signal transmission and shielding for richly detailed sound. 

Effortless Acoustics with Natural Flow

The open-back design of IM4 minimizes internal reflections and pressure buildup, creating a more open, natural sound with reduced fatigue. The rear chamber is filled with acoustic damping material to absorb standing waves, reducing distortion and harshness. The IM4 was tuned with listener feedback to ensure smooth, balanced sound across genres. 

Comfortable Fit

Developed with insights from millions of hearing-aid fitting samples, the ergonomic housing adapts to diverse ear shapes, delivering a secure and seamless fit. Crafted from CNC-machined aluminum alloy, IM4 offers a smooth touch that's gentle on the skin. The hollowed structure cuts the weight to just 38g, providing pressure-free comfort for long listening. 

Swappable Components

Sound Nozzles
Comes with both aluminum alloy and brass nozzles. Aluminum reduces sibilance with added brass; brass enhances mids and treble with clarity. 

Tuning Ear Tips
Includes three tuning sets: balanced, bass, and deep bass. Each available in S/M/L sizes. 

2-Pin 0.78mm Cable
The detachable 2-pin design supports 3.5mm and 4.4mm cable upgrades, allowing flexible customization. 

Specifications

• Driver: 10mm N52 Dual-Magnet Dual-Cavity Dynamic driver
• Diaphragm: PU Beryllium-coated
• Sensitivity: 109dB/mW
• Impedance: 21 ohms
• Frequency Response: 20Hz-20kHz
• Connector: 2-pin 0.78mm
• Audio Jack: 3.5mm Gold-plated plug
• Weight: 38g

Crafted With an Ultra-Thin Diaphragm, High-powered Magnetic System, and a Precision Acoustic Design, the i5 Delivers a Truly Likelife Listening Experience

• Open-back planar magnetic headphones
• 97mm large driver with ultra-thin 2-micron diaphragm
• 44 High-strength N50 neodymium magnets for driver efficiency
• Suede leather headband, walnut wood frame with unique natural grain, and CNC-machined aluminum frame
  

97mm Large-Diaphragm Driver

The i5 is equipped with a massive 97mm driver and an ultra-thin 2-micron diaphragm, delivering exceptionally low distortion. The expansive surface area enhances resolution, dynamic impact, and transient speed, producing a remarkably natural and immersive listening experience.

Target Sputtering Technology

Utilizing advanced targeted sputtering technology, a highly conductive silver metal voice coil as thin as 1.3μm is precisely coated onto the diaphragm. This process significantly enhances sound refinement while ensuring durability, keeping excellent audio performance consistently stable over time.

Acoustic Mesh

The high-transparency rigid rear mesh structure provides stable air pressure damping and linear feedback. It smooths out frequency spikes and reduces nonlinearity, achieving an open, airy soundstage with ultra-low acoustic resistance. 

High-Strength N50 Neodymium Magnets

Each driver unit features 22 pieces of N50-grade neodymium magnets arranged symmetrically, ensuring precise and stable diaphragm vibration. This design enables accurate and swift dynamic response, effectively reducing nonlinear distortion to produce purer, more natural sound, faithfully reproducing the essence of music. 

Ergonomic Comfort

Breathable, Skin-Friendly Earpads: Soft, ventilated materials reduce pressure and heat buildup, promising long-term comfort.

Dual-Axis Earcup Arms: Allows seamless vertical and horizontal rotation for a custom fit to different head shapes, enhancing both comfort and stability.

Memory Metal Headband: Flexible yet durable, it maintains its shape while adapting to different head sizes for a secure fit.

Stepless Silicone Adjustment: Enables smooth, precise adjustments for a personalized and comfortable wearing experience.

Specifications

• Driver: Planar magnetic
• Max Sound Pressure Level: >120dB SPL
• Frequency Response: 10Hz-50kHz
• THD: < 1% @100dB SPL
• Sensitivity: 98dB/mW @1kHz
• Impedance: 28Ω
• Recommended Power: > 250mW
• Minimum Recommended Power: > 100mW
• Weight: 1.21lbs
• Dimensions: 6.30" x 4.52" x 9.45"

In the Box

• Fosi Audio i5 headphones
• 3.5mm cable
• 6.35mm adapter
• User manual

The Fosi Audio GR70 Features a Thoughtfully Selected Vacuum Tube Combination For a Highly Musical and Authentic Analog Sound

• Desktop vacuum tube headphone amp and preamp
• General Electric 5654W and Sovtek 6Ж4 replaceable tubes
• Features adjustable impedance, bass and treble control
• Supports 16- 300Ω headphone impedance

Quad-Tube Dual Amplification

Built with two replaceable General Electric 5654W and two Sovtek 6Ж4 vacuum tubes, the Fosi GR70 amp offers a customizable auditory experience. Immerse yourself in the authentic warmth and smoothness of analog audio. 

The 5654W tubes boost voltage, while the 6Ж4 tubes handle power amplification. This setup delivers balanced, transparent, and textured sound.

Vintage Charm with Modern Precision

The GR70 is a two-in-one headphone amp and preamp. Easily integrate this tube preamp into your home audio system with its multiple headphone jacks and RCA input/output options. This tube headphone amp preamplifier offers intuitive controls, including a large volume knob, dual-side ventilation holes, bass/treble controls, and high + low impedance mode switching.

Additional Features

Switchable Output Impedance
Ensures optimal control and cleaner sound across a wide range of full-size headphones and IEMs.

Efficient Cooling and Thermal Stability
Keeps dust out while maintaining airflow to protect internal components.

Compact, Yet Powerful
Crafted with a CNC-machined aluminum alloy body, the GR70 is both durable and refined. Despite its compact size, it delivers up to 300mW power output and 1.2V RCA output with SNR ≥97dB—offering warm, clean, and dynamic sound.

Two-in-One
It supports low and high impedance modes switching to adapt 16Ω-300Ω headphones, and features 6.35mm/3.5mm headphone jacks on the front and RCA Input/Output on the rear for home audio HiFi system integration.

Specifications

• Input: RCA
• Output: RCA, 6.35mm headphones, 3.5mm headphones
• Rated Power Output
  • Low Gain: 67mW/32Ω
  • High Gain: 830mW/32Ω
• Headphone Impedance
  • Low Impedance Mode: 16Ω-120Ω
  • High Impedance Mode: 120Ω-300Ω
• Frequency Response: 20Hz-20kHz (±1dB)
• SNR: ≥93dB
• Dynamic Range: 94dB
• THD
  • RCA OUT: ≤0.26%
  • PHONE: ≤0.5%
• Noise Floor
  • RCA OUT: ≤20uV
  • PHONE: 56uV
• Cross Talk
  • RCA OUT: -63dB
  • PHONE: -65dB
• Power Input: DC 12V/3A

In the Box

• Fosi Audio GR70 Tube Amp
• (2x) 6Ж4 Vacuum Tube
• (2x) 5654W Vacuum Tube
• 12V/3A power supply
• (2x) Tube cover
• User manual