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

The Fosi Audio M03 200 Watt TPA3255 Subwoofer Amplifier impresses with its compact size and powerful performance. With 200 watts of output power and the TPA3255 amplifier chip, it delivers crisp and clear audio, especially in the lower frequency range. Its mini mono-channel design makes it versatile for various audio setups, whether for home entertainment systems or car audio. Overall, it's a solid choice for those seeking high-quality audio amplification in a compact package. The base sounds great in my tv room

Using it to power a sub woofer, very easy setup

UPDATE: After using this amp for a few months, while I still think it's a good value for what it is at this price point, I'll say that the 300W rating is misleading. Normally amps are rated for their per-channel RMS capabilities, whereas in this case 300W is the peak power possible only using a 4 ohm load (half that if you're using 8 ohms). That means 140-150W RMS at 4 ohms, which certainly produces usable bass if used with a sub, but I've had the amp shut off once or twice due to clipping when driving it hard. Admittedly for that level of bass I should be using a stronger amp, but this is worth sharing.I had a couple old car subwoofers in my closet that I hadn't used in years, and when I got my hands on a box again I went looking for a way to power one of them in my living room to complement my Klipsch RB6 bookshelf speakers. I've used this Fosi Audio amp with both an Infinity Kappa 12" and Kicker CVR 12" (swapping between) and both sound solid. The bass extension goes low enough to rattle things on my walls even with this amp's volume at probably 65% in a medium-sized living room, and it's great to have the adjustable crossover.Some folks seemed to doubt whether this amp's claims of 300W were legit and I've not used a multimeter to check or anything, but I'll say that it seems to have no trouble driving my sub to nice home theater listening levels, and it's nice that it's small and doesn't take up a lot of space alongside the receiver. I've driven the sub hard enough that it's almost uncomfortable to be in the room with it for a good hour or two straight and the amp never got more than slightly warm. That's a good sign of efficient power.Build quality seems pretty good, and I like the click feature of the volume knob -- makes it easy to turn it up or down a couple clicks and have a tactile feel for precision. One area for improvement would be if the lines on the crossover knob were labelled so you knew what specific frequency you were cutting off at. As it is you're kind of guessing, but after a little back and forth of setting, sitting on the couch and listening, then getting up to adjust, I have it dialed in pretty well. Nothing about the amp feels cheap or rattles when you handle it, and I like that there are banana plug/twist style speaker connections on the back rather than cheap spring clips.It sounds good enough that my wife said, "Maybe we should get a second one and power the other sub." Any time there's wife buy-in on audio gear in the living room, it's a plus. :-)Would definitely recommend this to anyone who already has a sub and box looking for an affordable way to power it.

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_titleI 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.