V3 MONO

The V3 MONO is a monoblock high-power amplifier integrated with the Texas Instruments TPA3255 amplifier chip, suitable for speakers of 2Ω to 8Ω impedance. It implements Post-Filter Feedback (PFFB) technology, addressing the long-standing issue of load-dependency in Class-D amplifiers. 
Title
Introduction
Packing List
Specifications
Operation Guide
Frequently Asked Questions
Warranty Information
About Fosi Audio

Introduction

Thank you for purchasing the V3 MONO power amplifier. 
The V3 MONO is a monoblock high-power amplifier integrated with the Texas Instruments TPA3255 amplifier chip, suitable for speakers of 2Ω to 8Ω impedance. It implements Post-Filter Feedback (PFFB) technology, addressing the long-standing issue of load-dependency in Class-D amplifiers. This significantly improves distortion, linearity, and frequency response, enhancing sound purity and system efficiency.
The V3 MONO incorporates balanced (XLR/¼" TRS) and unbalanced (RCA) input modes, with the latter offering 25dB/31dB gain selection to meet diverse listening preferences. It also features an automatic standby function that activates after 10 minutes of no signal input, automatically waking upon signal reception, enhancing energy efficiency and convenience.

①    On/Auto/Off Switch
②    Input Mode Switch
③    RCA Input Gain Switch
④    RCA Input
⑤    XLR/¼" TRS Input
⑥    Passive Speakers Binding Posts
⑦    DC 32-48V Power connection

Packing List

Fosi Audio V3 Mono x1
48V/5A Power Supply Unit x1
User Manual x1

Specifications

Channel

1.0
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Amplifier Chip

Texas Instruments TPA3255
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Output Power

48V/5A: 240W@4Ω

32V/5A: 100W@4Ω
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Input

RCA, XLR, ¼" TRS
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Output

Passive Speakers (supports banana 
plug or bare wire connection)
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SINAD

XLR: 101dB
RCA: 93dB
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SNR

≥123dB
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Dynamic Range

≥123dB
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THD

＜0.006%
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Gain

XLR/¼” TRS: 20dB
RCA: 25dB, 31dB;
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Terminal Impedance

2-8Ω
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Frequency Response

10Hz-30kHz（±0.06dB）
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Input Voltage Range

DC 32-48V
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Operation Guide

Please ensure all connections are correct and secure before powering on.

1. Connect passive speakers to the V3 MONO through the speaker output terminals using speaker cables;
2. Select the appropriate cable (such as RCA or XLR) based on the audio source to be connected, and attach the source device to the V3 MONO's corresponding audio input port;
3. Connect the power supply included with the V3 MONO to its power input;
4. Switch the power to AUTO or ON to turn on the V3 MONO, and select the corresponding input mode.

Note:

1. The balanced input supports both XLR and ¼" TRS plugs.
2. In either AUTO or ON mode, the device remains powered on. In AUTO mode, it will automatically enter standby after 10 minutes without signal input and reactivate upon receiving a signal again; ON mode keeps the device continuously on.
3. The V3 MONO allows for two discrete op-amps rolling, offering varied audio experiences.
4. Switch the power to AUTO or ON to turn on the V3 MONO, and select the corresponding input mode.

Op-amp replacement steps:

A. Identify the op-amp to be replaced; the PCB is marked with the positions for the NE5532 op-amps.
B. Use tweezers to carefully remove the op-amp you wish to replace. Note the orientation of the op-amp; align the "1" marking or the circular/half-circular notch on the op-amp with the corresponding half-circle mark on the PCB before inserting it into the socket.
C. Ensure the op-amp is correctly oriented during installation to prevent damage.

Frequently Asked Questions

1. Why is there no sound output after a successful connection?
A.  Ensure all connections are correctly made;
B. Check if the power adapter and the amplifier's indicator lights are on;
C.  Confirm the correct input mode has been selected;
D. Try using different power sources and outlets;
E. Attempt with different audio sources, speaker cables, speakers, and input cables, and make sure the audio source is on and not set to the lowest volume.

 

2. No sound change after switching the gain switch?
The gain switch on the V3 MONO is only applicable for RCA input mode. 
When using RCA input, switching the gain will noticeably change the volume, with a higher gain providing a louder volume.

 

3. Will keep the V3 MONO constantly powered on damage the device?
Constantly powering the device can lead to wear and energy consumption. For those preferring not to frequently power the device on and off, it's advisable to set the power switch to AUTO mode. In this mode, if there's no signal input for 10 minutes, the device will automatically enter standby mode, ensuring safety without harming the device.

 

If you have any further questions, please contact our support team via support@fosiaudio.com

Warranty and Maintenance

Fosi Audio pledges to give a 24-month limited warranty and support from the date of purchase. If you encounter any problem when using our product, please contact our support team at support@fosiaudio.com.

About Fosi Audio​

Fosi Audio designs and builds innovative audio products with all your music in mind. Great sound, simple but elegant designs, high-quality materials, and truly useful features are what Fosi Audio is about. We sincerely hope you get as much enjoyment from our products as we’ve had to create them!

 

Our Website: www.fosiaudio.com 

Amazon Store: www.amazon.com/fosiaudio 

Facebook Page: Fosi Audio 

Youtube Channel: Fosi Audio 

Whatsapp: +86 13716612254 

After-Sales Service and Technical Support Email: support@fosiaudio.com
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