---
product_id: 58115674
title: "Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer"
brand: "fosi audio"
price: "€ 116.45"
currency: EUR
in_stock: true
reviews_count: 13
category: "Fosi Audio"
url: https://www.desertcart.hr/products/58115674-fosi-audio-m04-subwoofer-amplifier-for-home-theater-mono-channel
store_origin: HR
region: Croatia
---

# Class D efficient tech 100W output power Bass & frequency control Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer

**Brand:** fosi audio
**Price:** € 116.45
**Availability:** ✅ In Stock

## Summary

> 🎵 Elevate your bass game—because your home theater deserves to be legendary.

## Quick Answers

- **What is this?** Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer by fosi audio
- **How much does it cost?** € 116.45 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/58115674-fosi-audio-m04-subwoofer-amplifier-for-home-theater-mono-channel)

## Best For

- fosi audio enthusiasts

## Why This Product

- Trusted fosi audio brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Powerful 100W Output:** Drive your passive subwoofer with crystal-clear, room-shaking bass that commands attention.
- • **Tailored Bass Control:** Switch seamlessly between subwoofer and full-frequency modes for a customized audio experience.
- • **Compact & Sleek Design:** Fits effortlessly into any home theater setup—small footprint, big impact.
- • **Plug-and-Play Convenience:** Complete with power supply and easy wiring, get your system booming in minutes.
- • **Cutting-Edge Class D Amplification:** Stay cool and efficient with advanced digital tech that maximizes power without bulk or heat.

## Overview

The Fosi Audio M04 is a compact, high-performance mono subwoofer amplifier delivering 100 watts of clean power via a Texas Instruments Class D chip. Designed for passive subwoofers, it features selectable bass modes, a built-in low pass filter, and precise frequency control, all housed in a sleek, efficient enclosure. Perfect for millennials seeking premium sound quality and space-saving design, it revives and enhances your home audio setup with professional-grade clarity and punch.

## Description

Buy Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer: Amplifiers - desertcart.com ✓ FREE DELIVERY possible on eligible purchases

Review: Great little subwoofer AMP - Got this subwoofer amp to bypass the amp component of my active subwoofer which died months ago due to a peak in voltage. My amp was those that work in "stand-by" mode, so they are always powered up somehow. Replacing the board with a new one (original) was too expensive, even more expensive than what the sub costed me in the first place, so in order to not throw the box and the woofer cone to the trash, I decided to just rewire things up in order to bypass the sub's integrated amp, so I got this GREAT little FOSI amp to power my "now passive" sub. Things worked great and my sub is now back to life, shining again. The M04 Fosi Amp is a great choice as it is POWERFUL, noiseless (at least to my ear), very small and does not generate any important heat. It comes with a power adapter, so you only need the cables to connect the input signal and the output signal to the passive subwoofer. I used the convenient "bare wire connection" to hook the modified sub to the speaker output of the Fosi Amp. Worked NICELY. Quality of the M04 Fosi AMP is VERY GOOD, in a very neat, compact and ellegant BLACK enclosure. It is definitely worth the money, which is NOT AT ALL expensive, but quality exceeds by far the amount paid for this amp. Until now, i'm really loving it.
Review: Great price, great sound quality - Used this to hook up a sub to a sound system for my workout room. Works exactly as expected and I’ve had no problems. Very powerful on a Sony xplode that is probably 10 years old. Great price and great sound for such a simple piece of tech. Hooked to a boss receiver.

## Features

- High-Performance Mono Amplifier:The Fosi Audio M04 is a mono amplifier designed for driving passive subwoofers or speakers. It features the Texas Instruments TPA3116 chip and NE5532 op-amp, providing an output power of 100 watts for a 2-ohm subwoofer or speaker.
- Enhanced Bass Response:The M04 SUB amp is designed to improve the bass response of passive subwoofers. It features a selector switch that allows the user to switch between subwoofer bass amplifier and full-frequency mono amplifier modes.
- Compact and Robust Design:This mini amp has a small and robust design with a built-in low pass filter for subwoofers and a sub frequency control, making it practical and powerful. It uses highly efficient Class D technology that remains cool under demanding loads and doesn't take up much space.
- Superior Sound Quality:The home subwoofer amplifier can produce a deep, crisp, and clean low-frequency sound effect, making it an excellent addition to dedicated home audio receivers & amplifiers. It has been designed to enhance the sound and performance of your audio system at an affordable price.
- Complete Package:What You Get: M04 subwoofer amp x1, 19V/4.74A power supply x1, user manual x1.

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07942M4MC |
| Best Sellers Rank | #13,663 in Electronics ( See Top 100 in Electronics ) #60 in Audio Component Amplifiers |
| Brand | Fosi Audio |
| Customer Reviews | 4.4 4.4 out of 5 stars (490) |
| Date First Available | January 18, 2018 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 15.9 ounces |
| Item dimensions L x W x H | 5.2 x 3.5 x 1.4 inches |
| Item model number | M04 |
| Manufacturer | Fosi Audio |
| Maximum Supply Voltage | 19 Volts (DC) |
| Minimum Supply Voltage | 19 Volts (DC) |
| Mounting Type | Freestanding |
| Number of Channels | 1 |
| Output Power | 100 Watts |
| Product Dimensions | 5.2 x 3.5 x 1.4 inches |
| Specification Met | [Inf] Thd <= 0.04% and Frequency Range 20hz - 120hz |
| Voltage | 12 Volts (DC) |

## Product Details

- **Item dimensions L x W x H:** 5.2 x 3.5 x 1.4 inches
- **Manufacturer:** Fosi Audio
- **Maximum Supply Voltage:** 19 Volts (DC)
- **Minimum Supply Voltage:** 19 Volts (DC)
- **Voltage:** 12 Volts (DC)

## Images

![Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer - Image 1](https://m.media-amazon.com/images/I/51ghuLx4kZL.jpg)

## Questions & Answers

**Q: Will this power up passive subwoofers ?**
A: Yes, absolutely. That's the reason I bought it and it works just fine without spending a whole lot of money.

**Q: How hot does this amp run?  The unit I currently use is very hot to the touch even after a short while.**
A: This thing seems cool no issues

**Q: What is the input voltage range?**
A: Not sure what your question is about.  If you mean input power, it's spec'd. at 12-24 vdc.  It comes with a power brick rated at 19 vdc, 4.47 amps.  Input sensitivity is =< 280 mv...

**Q: I have a Harman Kardon reciver with a single rca sub connection. What cables do i need to hook my sub to this amp and the amp to my reciever**
A: You need 1/8 audio plug to RCA adapter ..

## Customer Reviews

### ⭐⭐⭐⭐⭐ Great little subwoofer AMP
*by A***M on February 16, 2024*

Got this subwoofer amp to bypass the amp component of my active subwoofer which died months ago due to a peak in voltage. My amp was those that work in "stand-by" mode, so they are always powered up somehow. Replacing the board with a new one (original) was too expensive, even more expensive than what the sub costed me in the first place, so in order to not throw the box and the woofer cone to the trash, I decided to just rewire things up in order to bypass the sub's integrated amp, so I got this GREAT little FOSI amp to power my "now passive" sub. Things worked great and my sub is now back to life, shining again. The M04 Fosi Amp is a great choice as it is POWERFUL, noiseless (at least to my ear), very small and does not generate any important heat. It comes with a power adapter, so you only need the cables to connect the input signal and the output signal to the passive subwoofer. I used the convenient "bare wire connection" to hook the modified sub to the speaker output of the Fosi Amp. Worked NICELY. Quality of the M04 Fosi AMP is VERY GOOD, in a very neat, compact and ellegant BLACK enclosure. It is definitely worth the money, which is NOT AT ALL expensive, but quality exceeds by far the amount paid for this amp. Until now, i'm really loving it.

### ⭐⭐⭐⭐⭐ Great price, great sound quality
*by D***Y on September 2, 2025*

Used this to hook up a sub to a sound system for my workout room. Works exactly as expected and I’ve had no problems. Very powerful on a Sony xplode that is probably 10 years old. Great price and great sound for such a simple piece of tech. Hooked to a boss receiver.

### ⭐⭐⭐⭐ Reliable and priced right.
*by R***N on September 14, 2025*

Works well with my setup. Connected a Rockville sub to my surround receiver and works flawlessly.

## Frequently Bought Together

- Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer
- FosPower RCA Y-Adapter (3 Feet), 1 RCA Male to 2 RCA Male Short Y Splitter Digital Stereo Audio Cable for Subwoofer, Home Theater, Hi-Fi - Dual Shielded | 24K Gold Plated
- Tan QY 2RCA to 2RCA Cable 3Ft, Gold-Plated 2 RCA Male to 2 RCA Male Stereo Audio Cable for Home Theater, HDTV, Gaming Consoles, Hi-Fi Systems (3Ft/1M)

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*Product available on Desertcart Croatia*
*Store origin: HR*
*Last updated: 2026-02-26*