The Fosi Audio V3 Mono 240W Monoblock Power Amplifier delivers powerful Class-D performance with a Texas Instruments TPA3255 chip and advanced Post-Filter Feedback (PFFB) technology for exceptionally clean, detailed sound. Featuring balanced XLR/1/4-inch TRS and unbalanced RCA inputs, selectable RCA gain, and premium Nichicon, ELNA, and WIMA capacitors, the V3 Mono provides flexible connectivity and high-fidelity amplification for compatible passive speakers. With an included 48V/5A power supply, automatic signal-sensing standby, replaceable op-amps, and an advanced cooling design, this compact single-channel amplifier is ideal for dedicated monoblock, dual-mono stereo, and multichannel audio systems.
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Fosi Audio V3 Mono 240W Monoblock Power Amplifier with 48V/5A Power Supply

Experience powerful, high-fidelity sound with the Fosi Audio V3 Mono Monoblock Power Amplifier, a compact Class-D amplifier designed to bring precision, clarity, and exceptional performance to your home audio system. Powered by the Texas Instruments TPA3255 amplifier chip and featuring advanced Post-Filter Feedback (PFFB) technology, the V3 Mono delivers up to 240 watts of rated power into 4 ohms with the included 48V/5A power supply. Its dedicated single-channel design allows each amplifier to independently power one passive speaker, making it an excellent solution for building a dual-mono stereo system, expanding a multichannel home theater setup, or providing dedicated amplification for demanding speakers.

Engineered for clean, accurate audio reproduction, the V3 Mono incorporates PFFB technology to address load-dependent performance variations commonly associated with Class-D amplifiers. By feeding the amplified signal back through the output filter, this advanced circuit design helps minimize distortion, improve frequency response consistency, and maintain accurate sound reproduction across a wide range of speaker impedances. With a signal-to-noise ratio of at least 123dB, total harmonic distortion below 0.006%, and a SINAD rating of 101dB through its balanced input, the V3 Mono delivers impressive clarity, dynamic range, and detailed musical presentation.

Designed for seamless integration into modern Hi-Fi systems, the Fosi Audio V3 Mono provides balanced XLR and 1/4-inch TRS connectivity through a shared combo input, along with a dedicated unbalanced RCA input. A convenient input selector lets you choose between balanced and unbalanced sources, while adjustable RCA input gain settings of 25dB and 31dB provide additional flexibility when matching the amplifier with different preamplifiers and source components. Supporting passive speakers with impedances ranging from 2 to 8 ohms, the V3 Mono can be integrated with a wide selection of bookshelf and floorstanding speakers. Pair two units together to create a dedicated stereo system with independent monoblock amplification for each channel.

Inside its durable aluminum chassis, the V3 Mono features carefully selected audio components, including Japanese Nichicon and ELNA capacitors, German WIMA capacitors, and Japanese Sumida inductors. An upgraded four-layer printed circuit board helps reduce electrical interference and optimize signal integrity, while two replaceable NE5532 operational amplifier positions allow enthusiasts to experiment with compatible DIP8 op-amps for personalized sound tuning. The amplifier's innovative full-body heat dissipation system places the TPA3255 chip in direct thermal contact with the chassis, allowing heat to dissipate through the enclosure. Dual side ventilation openings further improve airflow to support stable performance during extended listening sessions.

The Fosi Audio V3 Mono also includes practical features for everyday operation. Its three-position On/Auto/Off switch provides manual power control or automatic signal-sensing operation, allowing the amplifier to enter standby after approximately 10 minutes without an audio signal and automatically resume playback when a signal returns. This eliminates the need to manually power the amplifier on and off during regular use. With its compact footprint, premium components, balanced connectivity, and included 48V/5A power supply, the Fosi Audio V3 Mono is an excellent choice for listeners seeking powerful, efficient, and customizable monoblock amplification without the size and complexity of traditional high-power amplifiers.

Specifications

• Brand: Fosi Audio
• Model: V3 Mono
• Manufacturer Part Number: V3 MONO-48V5A
• Product Type: Monoblock power amplifier
• Amplifier Class: Class-D
• Audio Channels: 1.0 (single-channel monoblock)
• Amplifier Chip: Texas Instruments TPA3255
• Amplifier Technology: Post-Filter Feedback (PFFB)
• Rated Output Power with Included 48V/5A Supply: 240 watts × 1 into 4 ohms
• Supported Speaker Impedance: 2–8 ohms
• Frequency Response: 10Hz–30kHz (±0.06dB)
• Signal-to-Noise Ratio: At least 123dB
• Dynamic Range: At least 123dB
• Total Harmonic Distortion: Less than 0.006%
• SINAD with Balanced XLR Input: 101dB
• SINAD with RCA Input: 93dB
• Audio Input Connections: RCA and combined XLR/1/4-inch TRS
• Unbalanced Analog Input: 1 × RCA
• Balanced Analog Input: 1 × XLR/1/4-inch TRS combo jack
• Balanced Input Compatibility: XLR or 1/4-inch TRS cables
• Input Selection: Dedicated RCA/balanced input selector switch
• Balanced Input Gain: 20dB
• RCA Input Gain Settings: Selectable 25dB or 31dB
• Gain Selection: Rear-panel gain switch for RCA input
• Gain Switch Function: Adjusts RCA input gain; does not affect balanced input mode
• Speaker Outputs: 1 pair of speaker binding-post terminals
• Speaker Connections: Supports banana plugs and bare speaker wire
• Speaker A/B Selector: No
• Simultaneous Speaker Channels: 1
• Dual-Mono System Compatibility: Two V3 Mono amplifiers can independently power the left and right speakers in a stereo system
• Multichannel System Integration: Additional units can provide dedicated amplification for compatible individual home theater channels
• Operational Amplifiers: NE5532
• Replaceable Op-Amps: 2 replaceable dual-channel DIP8 op-amp positions
• Compatible Op-Amp Examples: Sparkos SS3602, MUSES02, OPA2604, Burson V5i, and other electrically compatible DIP8 dual operational amplifiers
• Capacitors: Japanese Nichicon and ELNA capacitors; German WIMA capacitors
• Inductors: Japanese Sumida inductors
• Circuit Board: Upgraded four-layer PCB
• Cooling System: Full-body chassis heat dissipation with dual side ventilation openings
• Thermal Design: Amplifier chip thermally coupled to the enclosure for efficient heat transfer
• Power Control: Three-position On/Auto/Off switch
• Automatic Signal Sensing: Yes
• Automatic Standby: After approximately 10 minutes without an audio signal
• Automatic Wake: Reactivates when an audio signal is detected
• 12V Trigger Input: No
• 12V Trigger Output: No
• Volume Control: No dedicated volume adjustment; designed for use with a compatible preamplifier or variable-output source
• Bass and Treble Controls: No
• Power Input: DC 32–48V
• Included Power Supply: 48V/5A DC external power adapter
• Included Power Supply Rating: 240W
• Chassis Construction: Compact metal enclosure with integrated heat dissipation
• Dimensions: 105 × 35 × 142mm (approximately 4.13 × 1.38 × 5.59 inches)
• Weight: Approximately 480g (1.06 lbs)
• Bluetooth Connectivity: No
• Wi-Fi Connectivity: No
• Built-In Music Streaming: No
• Apple AirPlay: No
• Built-In DAC: No
• Digital Audio Inputs: No
• HDMI Inputs: 0
• HDMI Outputs: 0
• Subwoofer Output: No
• Headphone Output: No
• App Control: No
• Remote Control: No
• EAN: 6976136960447
• Manufacturer Warranty: 24-month limited warranty
• Included Accessories: Fosi Audio V3 Mono Power Amplifier, 48V/5A power supply, and user manual

What It's Great At

• Powerful Dedicated Monoblock Amplification: The Texas Instruments TPA3255 Class-D amplifier delivers 240 watts of rated power into 4 ohms with the included 48V/5A power supply, providing dedicated amplification for a single passive speaker.
• Building Dual-Mono Stereo Systems: Pair two V3 Mono amplifiers to independently power the left and right speakers, creating a flexible stereo setup with dedicated amplification for each channel.
• Accurate Sound with PFFB Technology: Post-Filter Feedback circuitry minimizes load-dependent frequency response variations and distortion, helping deliver clean, detailed audio across compatible speaker loads.
• Balanced and Unbalanced Connectivity: A combined XLR/1/4-inch TRS balanced input and dedicated RCA connection provide convenient compatibility with a wide range of preamplifiers, DACs, and line-level audio sources.
• Premium Audiophile Components: Nichicon, ELNA, and WIMA capacitors, Sumida inductors, and an upgraded four-layer PCB support low-noise, high-fidelity performance, while replaceable op-amps allow additional customization.
• Efficient Cooling and Automatic Operation: Full-body chassis heat dissipation, side ventilation, and automatic signal-sensing standby provide reliable performance with convenient everyday operation.

FAQ Section

Q: How much power does the Fosi Audio V3 Mono deliver?
A: The Fosi Audio V3 Mono delivers a manufacturer-rated 240 watts into 4 ohms with the included 48V/5A power supply. It uses a Texas Instruments TPA3255 Class-D amplifier chip with PFFB technology to provide efficient, low-distortion amplification for a single passive speaker. Actual output depends on speaker impedance and operating conditions.

Q: Is the Fosi Audio V3 Mono a stereo amplifier?
A: No. The V3 Mono is a single-channel monoblock amplifier designed to power one passive speaker. To create a traditional two-channel stereo system, you will need two V3 Mono amplifiers, with one powering the left speaker and the other powering the right speaker.

Q: Does this version of the Fosi Audio V3 Mono include the 48V power supply?
A: Yes. This version includes one 48V/5A external power supply and is rated to deliver 240 watts into 4 ohms. The V3 Mono is also available in other power supply configurations, but this particular model includes the 48V/5A adapter.

Q: What audio inputs does the Fosi Audio V3 Mono have?
A: The V3 Mono includes one RCA unbalanced input and one balanced XLR/1/4-inch TRS combo input. A dedicated switch allows selection between RCA and balanced input modes. The RCA input also includes selectable 25dB and 31dB gain settings for matching different source components.

Q: Does the Fosi Audio V3 Mono have a 12V trigger?
A: No. The V3 Mono does not include a dedicated 12V trigger input or output. Instead, it features automatic signal-sensing operation. When set to Auto mode, the amplifier enters standby after approximately 10 minutes without an audio signal and automatically reactivates when a signal returns.

Q: What speakers are compatible with the Fosi Audio V3 Mono?
A: The V3 Mono supports passive speakers with impedances ranging from 2 to 8 ohms. It can be used with many bookshelf and floorstanding speakers, provided their power handling and electrical requirements are compatible. Each V3 Mono amplifier powers only one speaker, so a stereo pair requires two amplifiers.

Q: Can I replace the op-amps in the Fosi Audio V3 Mono?
A: Yes. The V3 Mono includes two replaceable DIP8 operational amplifier positions, allowing enthusiasts to experiment with compatible aftermarket op-amps. Options include models such as the Sparkos SS3602, MUSES02, OPA2604, and compatible Burson designs. Always confirm electrical compatibility and correct installation orientation before replacing components.

Q: Does the Fosi Audio V3 Mono have Bluetooth, streaming, or a built-in DAC?
A: No. The V3 Mono is a dedicated analog power amplifier and does not include Bluetooth, Wi-Fi, music streaming, a built-in DAC, or digital audio inputs. To play music from digital sources, connect a compatible external DAC, music streamer, or preamplifier with RCA or balanced analog output. A preamplifier or variable-output source is recommended for volume control.