--- product_id: 147513418 title: "M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply" brand: "fosi audio" price: "¥32425" currency: JPY in_stock: true reviews_count: 13 category: "Fosi Audio" url: https://www.desertcart.jp/products/147513418-m03-200-watt-tpa3255-subwoofer-amplifier-mini-mono-channel-audio store_origin: JP region: Japan --- # Texas Instruments TPA3255 chip 200W max power output Switchable SUB/Full-frequency modes M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply **Brand:** fosi audio **Price:** ¥32425 **Availability:** ✅ In Stock ## Summary > 🎵 Unleash deep, clean bass that commands attention — your subwoofer’s new best friend! ## Quick Answers - **What is this?** M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply by fosi audio - **How much does it cost?** ¥32425 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.jp](https://www.desertcart.jp/products/147513418-m03-200-watt-tpa3255-subwoofer-amplifier-mini-mono-channel-audio) ## 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 - • **Cutting-Edge Tech:** Equipped with TI’s TPA3255 chip featuring PurePath Ultra-HD for ultra-low distortion and crystal-clear sound. - • **Compact & Versatile:** Mini mono channel design fits anywhere—perfect for desktop setups or discreet home theater integration. - • **Dual Mode Flexibility:** Seamlessly switch between full-frequency mono amp and dedicated subwoofer modes to suit your setup. - • **Powerhouse Performance:** Delivers up to 200 watts of clean, distortion-free audio power for immersive home theater bass. - • **Precision Bass Control:** Built-in low pass filter with adjustable SUB frequency lets you tailor deep bass to your exact preference. ## Overview The Fosi Audio M03 is a compact, high-efficiency 200W mono amplifier powered by the advanced Texas Instruments TPA3255 chip. It offers switchable modes for full-frequency or dedicated subwoofer use, featuring a built-in low pass filter and SUB frequency control. Designed for home theater and Hi-Fi enthusiasts, it delivers ultra-low distortion sound with versatile connectivity, making it ideal for upgrading passive subwoofers or bookshelf speakers. ## Description desertcart.com: Fosi Audio M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply : Electronics Review: A powerful driver for a sub woofer - UPDATE: The TAPE out hookup I mentioned below worked great for levels, but TAPE out is, by design, not controlled by the volume knob on my Pioneer receiver, so I had to constantly adjust two knobs, one under my desk at the sub, so not ideal. The solution? I just added a $25 preamp before the FOSI to have excellent subwoofer levels from the Pioneer subwoofer output, plenty of signal now at half volume or less on both the preamp and the FOSI main amp. The preamp is also a simple and excellent little device. https://www.desertcart.com/dp/B0945RFJ6Z?ref=ppx_yo2ov_dt_b_fed_asin_title I went with this preamp instead of some units, like the FOSI preamp, because it does NOT do any RIAA equalization that I did not want to add to the mix. I bought this FOSI to get my 24 year old KLH subwoofer running again. I am very pleased. I was able to remove the plate amp assembly and leave the SW box sealed on the back as it has always been, by the plastic box that had housed the circuitry. I might mount the FOSI in this plastic recess, but for now it sits atop the SW cabinet and if its rubber feet keep it from walking off I will just leave it there for ease of reaching the controls. This tiny powerhouse is driving the 8" KLH speaker to make better sounds and deep vibrations, than it has for years. Gone are the occasional deep pop and rattle sounds that I had thought might mean the speaker cone itself had deteriorated. It turns out the old cone is just fine. The KLH built in amp had apparently been slowly cooking its circuit board for a long time before it gave up completely last week. It looks like a bulging cap and some burned resistors... maybe I will fix that board someday. One word of warning. I was driving the old KLH ASW 100 powered subwoofer with an RCA Y-cable from the low level sub output RCA jack of a 20 year old Pioneer home theater amp. It turns out that the signal level on that jack is too low to get more than just a faint response from this FOSI, even turned up to the max. So don't assume this will be a direct replacement if you have that kind of subwoofer hookup. I ended up driving this FOSI with a dual RCA cable from the tape record outputs of the Pioneer, and I am getting loud, clear and rumbling bass from the FOSI at only about four clicks of the volume knob. The FOSI volume and freq cutoff controls have a nice, subtle, detent feel. Review: This is the solution to any passive subwoofer! - I have a lot of experience with these Fosi Audio amplifiers. They never cease to amaze me. As you can see in the video, I have a subwoofer hooked up to this mono amp. I converted the subwoofer to passive because the internal amp fried. Those replacement amps are expensive while the Fosi amps Are perfect for this situation and sound amazing and caused less. Plus they're tiny, easy to hook up. Have clean sound with no distortion. They weigh basically nothing and you can put them just about anywhere. If you're an audio person or you mess with home theater or anything like that or you just want to test subwoofers this is the perfect amp for it. I keep one on my test bench as well. ## Features - Subwoofer Amplifier and Full-Frequency Mono Amp: The audio amplifier offers versatile functionality with two modes. Switch to PBTL mode to use it as a full-frequency mono amplifier for driving passive speakers and powered subwoofers. Switch to SUB mode to use it as a dedicated subwoofer amplifier for driving passive and powered subwoofers. - Advanced Audio Technology: The audio receiver utilizes the Texas Instruments TPA3255D2 chip, featuring an advanced integrated feedback design and proprietary high-speed gate driver error correction (PurePath Ultra-HD). This technology ensures ultra-low distortion across the audio band, delivering superior audio quality. - High-Efficiency Power Output: The power amplifier provides high-efficiency power output up to 200 watts. It can deliver 150 watts RMS into 4-ohm loads or 120 watts into 8-ohm loads. (Note: The package includes a 32V/5A power supply, but a more powerful power supply is needed to achieve the maximum power output.) - Home Hi-Fi Amplifier with Clean Sound Quality: The home stereo receiver is designed for home Hi-Fi systems, offering clean sound quality. It features a built-in low pass filter for 20-300Hz subwoofers with SUB frequency control, making it an excellent amplifier for driving any bookshelf speaker or subwoofer. - What You Get:M03 amp x1, 32V/5A power adapter x1, and user manual x1. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B07VHG2LR9 | | Best Sellers Rank | #24,819 in Electronics ( See Top 100 in Electronics ) #114 in Audio Component Amplifiers | | Brand Name | Fosi Audio | | Customer Reviews | 4.3 out of 5 stars 797 Reviews | | Item Dimensions | 5.12 x 4.13 x 1.37 inches | | Item dimensions L x W x H | 5.12 x 4.13 x 1.37 inches | | Manufacturer | Fosi Audio | | Maximum Output Power | 200 watts | | Maximum Supply Voltage | 32 volts_of_direct_current | | Minimum Supply Voltage | 24 volts_of_direct_current | | Model | M03 | | Mounting Type | Surface Mount | | Number of Channels | 1 | | Number of Items | 1 | | Number of Packs | 1 | | Package Type Name | Box" or "Case | | Part Number | Ｍ03 | | Unit Count | 1 Count | | Voltage | 220 volts | | Warranty Description | 18-month manufacturer | ## Product Details - **Item dimensions L x W x H:** 5.12 x 4.13 x 1.37 inches - **Manufacturer:** Fosi Audio - **Maximum Supply Voltage:** 32 volts_of_direct_current - **Minimum Supply Voltage:** 24 volts_of_direct_current - **Voltage:** 220 volts ## Images ![M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply - Image 1](https://m.media-amazon.com/images/I/51zTVamBsHL.jpg) ## Questions & Answers **Q: If the power going in to this unit is 32v 5amp = 160 watts. How is this unit rated 300 watts?** A: I tested the continuous wattage output using the 32v 5amp supply that comes with it. I get 50 watts driving 8 ohm, 100 watts driving 4 ohm and 200 watts driving 2 ohm. I tested with a scope and sine wave. You get about 20 volts RMS before the sine wave starts to square off at the peaks. The 50 watts at 8 ohms is surprisingly loud but my 8 ohm speaker is very efficient Electrovoice EVM15 in a Thiel box. **Q: I can't seem to fine the rms watts. does anyone know the true specs? power at 2 ohms, at four ohms. peak does not mean much.** A: I put it on an oscilloscope and fed it a sine wave across a 2 ohm, 4 ohm and 8 ohm load resistor. Using the power supply that it comes with this unit (32V 5A) I see the sine wave start to clip right around 20 volts RMS. It works out to 50 watts with an 8 ohm load, 100 watts with 4 ohm load and 200 watts with a 2 ohm load. **Q: What is the maximum voltage and current can be used as it comes with 32VDC at 5 amp.** A: The power supply current rating of 5A is not quite enough to get the maximum rated output, but it doesn't fall short by much. There are tradeoffs with duty cycle, thermal management, equipment life, program spectral characteristics, etc. but they don't really amount to more than giving precision to common sense. All you need to know is that you can always use a higher current supply without any concern. A 10A supply will run cooler, longer, and cleaner. It is the voltage that has to be in bounds and for this chip TI specifies the working range to be 24-35V and the maximum power to be 300 Wrms. If you want to upgrade get a 36V unit rated over 300 watts, e.g. Mean Well MW LRS-350-36 (9.7A) AND turn the voltage down to 35V or less. **Q: If using as a full-frequency mono amp to a passive speaker, can the RCA output still go to a powered sub with the frequency control for the sub only?** A: Yes, ## Customer Reviews ### ⭐⭐⭐⭐⭐ A powerful driver for a sub woofer *by G***S on December 18, 2024* UPDATE: The TAPE out hookup I mentioned below worked great for levels, but TAPE out is, by design, not controlled by the volume knob on my Pioneer receiver, so I had to constantly adjust two knobs, one under my desk at the sub, so not ideal. The solution? I just added a $25 preamp before the FOSI to have excellent subwoofer levels from the Pioneer subwoofer output, plenty of signal now at half volume or less on both the preamp and the FOSI main amp. The preamp is also a simple and excellent little device. https://www.amazon.com/dp/B0945RFJ6Z?ref=ppx_yo2ov_dt_b_fed_asin_title I went with this preamp instead of some units, like the FOSI preamp, because it does NOT do any RIAA equalization that I did not want to add to the mix. I bought this FOSI to get my 24 year old KLH subwoofer running again. I am very pleased. I was able to remove the plate amp assembly and leave the SW box sealed on the back as it has always been, by the plastic box that had housed the circuitry. I might mount the FOSI in this plastic recess, but for now it sits atop the SW cabinet and if its rubber feet keep it from walking off I will just leave it there for ease of reaching the controls. This tiny powerhouse is driving the 8" KLH speaker to make better sounds and deep vibrations, than it has for years. Gone are the occasional deep pop and rattle sounds that I had thought might mean the speaker cone itself had deteriorated. It turns out the old cone is just fine. The KLH built in amp had apparently been slowly cooking its circuit board for a long time before it gave up completely last week. It looks like a bulging cap and some burned resistors... maybe I will fix that board someday. One word of warning. I was driving the old KLH ASW 100 powered subwoofer with an RCA Y-cable from the low level sub output RCA jack of a 20 year old Pioneer home theater amp. It turns out that the signal level on that jack is too low to get more than just a faint response from this FOSI, even turned up to the max. So don't assume this will be a direct replacement if you have that kind of subwoofer hookup. I ended up driving this FOSI with a dual RCA cable from the tape record outputs of the Pioneer, and I am getting loud, clear and rumbling bass from the FOSI at only about four clicks of the volume knob. The FOSI volume and freq cutoff controls have a nice, subtle, detent feel. ### ⭐⭐⭐⭐⭐ This is the solution to any passive subwoofer! *by T***S on March 18, 2026* I have a lot of experience with these Fosi Audio amplifiers. They never cease to amaze me. As you can see in the video, I have a subwoofer hooked up to this mono amp. I converted the subwoofer to passive because the internal amp fried. Those replacement amps are expensive while the Fosi amps Are perfect for this situation and sound amazing and caused less. Plus they're tiny, easy to hook up. Have clean sound with no distortion. They weigh basically nothing and you can put them just about anywhere. If you're an audio person or you mess with home theater or anything like that or you just want to test subwoofers this is the perfect amp for it. I keep one on my test bench as well. ### ⭐⭐⭐⭐ It can't be 200 watts. With that being accepted, this is worth every penny. *by F***Y on December 10, 2020* A few months ago the amp in my long time favorite subwoofer passed on with the, all too familiar, whiff of ozone. After paying for repair and the 80 bucks in shipping, unfortunately, the gentleman who did the repair passed while the amp was in transit. This is just a preface to what I am posting about today. I picked up one of the new mini amps that I am seeing more of in new builds. This thing is tiny in comparison to any of my other equipment. It is about 5"x6"x1 1/2". Expectations were not very high, especially after the 200w claim from a 2.2 amp power supply. The math doesn't work, but that's against the point of this post. I bought it for experimentation in other projects. Tonight I hooked it up to the 650w JBL driver in my sub that has caused me great sorrow over the last few months. I have to admit, I am pleasantly surprised. Obviously the driver excursion wasn't there, as expected, however the musicality of the bass was. I have no doubt at this point that the build quality is there. Future projects will include this amp. Knowing that the wattage is overrated, to say the least, the performance was there. ## Frequently Bought Together - Fosi Audio M03 200 Watt TPA3255 Subwoofer Amplifier Mini Mono Channel Audio Power Amp for Home Theater Full-Frequency and SUB Bass Switchable with 32V/5A Power Supply - 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 - Dayton Audio IOSUB 10" IP66 Subwoofer 150 Watts RMS at 4 Ohms Impedance - Durable Weather-Resistant Indoor/Outdoor Speaker --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.jp/products/147513418-m03-200-watt-tpa3255-subwoofer-amplifier-mini-mono-channel-audio](https://www.desertcart.jp/products/147513418-m03-200-watt-tpa3255-subwoofer-amplifier-mini-mono-channel-audio) --- *Product available on Desertcart Japan* *Store origin: JP* *Last updated: 2026-09-25*