








Product description
The video showcases the product in use.The video guides you through product setup.The video compares multiple products.The video shows the product being unpacked. Fosi Audio V3 Mono Mini Power Amplifier Merchant Video

Continuation of Co-Creation
Engineered for Audiophiles – Optimal Choice for Home Audio Systems
We listen intently, record diligently, and develop with dedication, ultimately striving to transform your suggestions and ideas into reality—the V3 mono.
Input: RCA, XLR, ¼” TRS; Output: Passive Speaker (supports banana plug or bare wire connection)、Passive subwoofer.SINAD: XLR–101dB; RCA–93dB; SNR: ≥123dBRated Power Output: 48V/5A 240W@4Ω; 32V/5A 100W@4Ω; 48V/5A–115W@8Ω; Maximum Power Output: 48V/10A 300W@4Ω.
Post-Filter Feedback Technology Integrated
Significantly reduces distortion, enhances linearity and frequency response to get superior sound.
Compact Yet Powerful
Crafts an immersive sound experience, satisfying your craving for superior musical quality.
Accurate Imaging with Zero Crosstalk
Enhances stereo depth and soundstage accuracy for a purer audio experience.
Easily Replaceable DIP8 Dual Discrete Op-amps
Meeting your pursuit of a personalized audio experience

1 PFFB Technology
2 Rated Power 240W
3 Pure Sound
4 Swappable Op-Amp Design
5 Power Rating
Provides You with Flexible Connectivity Options
Effortlessly switched by a toggle switch, easily adapted for both home and professional scenarios.
Advanced Cooling Design
Long-term efficient operation of the amp, prevents overheating.
With Minimalist Design
Effortlessly integrates into various settings like home theater, study room, desktop, and studios.
Automatic Signal Sensing
Enters standby after 10 minutes of no signal input, effectively reducing power consumption.
1 XLR Balanced & RCA Inputs
2 Premium Components
3 Heat Dissipation Design
4 Compact and Exquisite
5 Auto Power
Premium Internal Components 
NICHICON Caps, Japanese
Ensure superior sound clarity, longevity, and stable electrical performance, enhancing the fidelity of audio reproduction.

WIMA Caps, German
Provide exceptional sound quality and signal stability, greatly enhancing the audio experience.

ELNA Caps, Japan
Ensure enhanced audio clarity and stability, contributing to a richer sound experience.

Sumida Inductor, Japanese
Offers superior signal purity and noise reduction, elevating the amplifier’s sound performance.
No sound change after switching the gain switch?
The gain switch on the V3 MONO only works with the RCA input. When using RCA mode, switching the gain setting will noticeably change the volume. (If it’s already set to RCA mode, the output level from the preamp is usually sufficient.)
Would the noise still occur if no audio input cables are connected?
Try replacing the audio source, using well-shielded audio cables, and switching to a different speaker.
Doesn’t work in standby mode?
Use a separate power supply and power strip for each V3 MONO to avoid ground-loop noise affecting the standby function; if the light dims but the unit doesn’t automatically shut down, please try replacing high-quality RCA cables.
V3 MONO don’t have volume control or knobs?
Yes. V3 MONO is a pure power amplifier, it is recommended to use it with a DAC, preamplifier, or player with volume control.
What’s the V3 MONO?
V3 MONO is a mono channel amplifier. To achieve 2 channel amplifier effect, two V3 MONO are needed to connect two speakers.
Friendly Solutions Guide
1. Heat Dissipation
– It is recommended to use V3 MONO within the rated power range to avoid overheating. (Rated Power 240W, Maximum Power 300W)
– Place V3 MONO in a cool and ventilated working environment or use it with a cooling fan. It also can attach an aluminum heat sink to the top with a thermo-transferring adhesive to achieve effective heat dissipation
2. Function Troubleshooting
– Ensure all wiring is correct (connect the positive speaker wire to the amplifier’s positive terminal, the negative to the negative terminal, and make sure the speaker wires do not touch each other, as this could cause a short circuit and potentially damage the amplifier). —In AUTO mode, if no signal is detected for 10 minutes, the V3 MONO will automatically enter standby mode to save energy, and will reactivate upon detecting a signal, combining convenience with energy efficiency. Ensure a stable signal connection.
3. Audio Sound Quality:
– Sound Volume: The V3 Mono is a pure power amplifier with no volume control or knobs. It has a gain of 19 dB / 25 dB for RCA inputs and a fixed gain of 20 dB for XLR inputs. It can be adjusted to above 19dB to increase the volume and output power.
– Audio Quality: Different audio source qualities affect the sound quality. It is recommended to use high-quality, lossless audio files, such as FLAC, WAV and other formats, to obtain a better sound quality experience. V3 MONO supports impedance of 4-8Ω. Speaker impedance that is too low or too high will cause unstable amplifier output and affect the sound quality performance.— Please replace with a high-quality RCA cable with good shielding to prevent noise.
4. Compatibility:
– NOT Compatible: Active Subwoofer, Bass Shaker, Bass Audio,Bluetooth, USB/COA/OPT decoding amplifier, and does not support headphone amplifiers.— Suggest Burson V7 Vivid opamps with soft extension cable.
Mini Monoblock Amplifier: Crafted for HiFi audiophiles, the amplifier home audio allows you to drive a single passive speaker with one amp, delivering up to 240W @4Ω of rated power. It offers the flexibility to build your home audio 2/3/4/5-channel system effortlessly. The V3 Mono can serve as a power amplifier for multi-channel AVRs, complementing the output power to easily drive high-power speakers in home theater systems.
Innovative Cutting-Edge Technology: Fosi Audio has achieved a technological breakthrough through independent research and development by applying PFFB (Post-Filter Feedback) technology to the V3 Mono for the first time. This effectively overcomes the common load dependency issues of Class-D amplifiers, improving distortion and enhancing frequency response, thereby significantly enhancing sound quality and performance.
Audiophile-Grade Components: The audio component amplifiers incorporates the high-end TPA3255 Class-D amp chip, paired with well-known components such as Japanese Nichicon filter capacitors, ELNA capacitors, German WIMA capacitors, and Japanese Sumida inductors, etc. Additionally, it features an upgraded four-layer PCB. This combination not only ensures high power output but also achieves a THD as low as 0.006%, a SINAD of 101dB, and an SNR of 123dB. As a result, the fidelity and quality of the audio are assured.
Advanced Cooling: Utilizing Fosi Audio’s pioneering full-body heat dissipation design, the TPA3255 amplifier chip is placed at the bottom and tightly integrated with the chassis, allowing heat to be effectively dissipated through the casing. Coupled with dual side ventilation holes that enhance internal airflow, this ensures the stereo amplifier can deliver stable, high-power output over extended periods.
User-Friendly Design: Supports both XLR/¼” TRS balanced and RCA single-ended(with gain selection) inputs, with an easy toggle switch for selection. Additionally, it features an auto power/signal sensing mode to enhance energy efficiency. You can also customize your preferred sound signature by replacing the stock NE5532 op-amps, supporting DIP8 dual discrete op-amps. For example, it will work with Sparkos SS3602, MUSES02, OPA2604, Burson V5i, V6, V7, and more. Note: Please ensure that the device is powered off when connecting the speaker cable.
$139.99