Review on 🔊 Fosi Audio M02 Subwoofer Amplifier Home Theater Power Amp - Mono Channel, 100Watt by Derrick Villarreal

I had a 4 way speaker with a 12" woofer that I thought I could turn into a subwoofer. All I needed was an amp. This one is perfect. It's tiny, fits in the palm of your hand, and reproduces sound without distortion. It has a control that allows you to adjust the frequency at which the subwoofer will turn on. You should NOT switch on the mids, otherwise you will lose the channel separation and the subwoofer will not be able to reproduce them anyway. I place the slider roughly in the middle. The sensitivity control is spot on and produces a lot of midrange sound. It comes with a power supply that works well - there is no noise or noise generated by the block. Power delivery is a bit overrated. It is mathematically impossible to get 100W RMS from this unit. The power pack has a nominal voltage of 19 volts at 4.7 amps. Since watts = volts x amps, this means the device can only deliver 89 watts. Because some of that power is dissipated as heat in the block, we call it 80 watts. This is at 4 ohms. If your speaker is 8 ohms, you should cut the power in half. So expect about 40W RMS into 8 ohms. And not always - the amp has no cooling fins and no way to dissipate heat, so it shuts down if you use high power for a long time. I like to use it as a subwoofer amplifier on the PC to play music and games at a sufficient volume. If your needs are more intense, consider a plate amp that's built for continuous, high-power use. Pushing the switch turns the amp into a very powerful amp (NOTE: mono, not stereo) with a flat frequency response that can solve many needs. All in all this is a very good subwoofer or mono amp as long as you understand that it has some limitations.