Bought this amp 4 years ago, and the junk 32v / 5a Power Supply has been going out for almost a year now (it was NEVER a very good power supply). Contact Fosi Audio for support, and their advice was to buy another amp. So that's exactly what I'm going to do, from another manufacturer that'll actually support their products. I was just simply asking what power supply I could replace it with that's not going to fry the thing.

WHEN THE AMP WORKS, it works fine. It never did do rated power though. Left it an extra star for the roughly 3 years I was able to enjoy it at low volume.

Nice amp, small size and with simple yet powerful features. For your sub this does the job well, and is a product that works.

I just wished they included and option to buy with a more powerful power supply.

Works great for my set up!

I purchased this to replace the blown amp in a JBL B212 ultra base. The original amp was 75W and it was driving a 12" replacement speaker. I attached this to a speaker output on a Marantz 2216 and couldn't be happier with the results. The frequency cutoff adjustment is awesome and so is the volume adjustment which allows you to bend it perfectly with the L212 tower speakers accompanying it. My only recommendation for improvement is labeling the frequency cutoff range on the dial to know roughly where it's set.

Wow! What an amp! This thing is going to change your life - and for the better. Because only a fool grovels on the dusty floor with a flashlight and a bad attitude, to change the settings on their subwoofer.

Having fingertip control of both SUBFREQ and SUBVOL opens up a whole new world of Hifi listening pleasure! Now you can change how hard your system bumps according to your mood and your music. Now you can have low volume music with full bass - JUST AS OUR LORD FOSI INTENDED!

And, the versatility of this tiny amp is tremendous: it can be used to drive defunct powered subwoofers, simply by bypassing the blown up subwoofer amp! This means, you can now buy blown up subwoofers at $40 or $50 each, and with the money you save, you can easily afford to buy this unit - which now comes as standard with the 48v 5A PSU - which you will be wanting!

On top of the speaker outlets for the passive subwoofer, you can also attach a powered sub to the subwoofer pre-amp output of the amplifier, and so you get double value by driving two subwoofers for the price of just one amp, and you get to control both with the same unit!

This gives you even MORE control, over your bass, and allows you to place a subwoofer directly underneath each front speaker, and both subs are putting out the same (mono) signal, so there is little chance of stereo bass interfering with each speaker's output. Turns out that 2.2 is superior to 2.1 systems!

Chat-GPT will help you properly locate and tune your subwoofer(s) to ensure you are getting the best out of them - and it will also guide you through the process of mass-damping and isolating your subwoofers, to greatly improve their performance, without spending more than $10 per subwoofer.

If I could make some small changes to this amp, or provide feedback for the upcoming "M03 Pro mono subwoofer amp" then it would have a Trigger In on the back, and a Phase potentiometer on the front of the unit, and each knob would have a scale around it: Degrees on the Phase, Hz on the SUBFREQ and 0-11 (of course!) on the Volume knob.

Lastly, this amp would sell a lot better if it were presented in the same form factor as the ZA3 and ZD3 which look amazing.

I have ordered my second M03 already, and I am accumulating blown up subwoofers to create incredibly good Class-D 2.1 and 2.2 systems for myself, my friends, and my family, who are all blown away by the truly baffling quality of Fosi's Class-D products.

This subwoofer amp has brougth life to my 2005 vintage Sony make 180watt passive subwoofer . I am using M0-3 Amp as Subwoofer amp. Connected from subwoofer output of ZA-3 AMP . This setup is working absolutely fine. I am happy with this setup.

Just got this unit and wow. I didn't expect such power from such a small device. I ordered the M03 because the amp in my powered Klipsch 12" sub would clip with very little gain. I knew I had to do something and this little amp came to the rescue. I've tested this unit with high gain and my sub has never played with such intensity that I can remember. So far 5 stars and I hope it stays there with long usage.

I hooked the M)3 amp to the ZP3 preamp to drive my spare Rockford Fosgate P3SDH10 subwoofer which I took out from my old car. I was able to adjust the crossover and the bass blends well with my Sonus Faber Sonetto G1 Speakers. Happy with the improved bass extension

Nice unit, works well, even drives a 2ohm load.

Works well enough for my 15" sub (150W RMS, 8 ohms), but the fact that it comes underpowered from the factory and I have to buy a new power supply and can't just choose which one I want (priced accordingly, even!) feels like a deliberate gouge from Fosi.

Its an amazing subwoofer amplifier, works perfectly fine and also looks pretty nice!

Great value amp. Doesn't sound as nice for a main speaker but great for a low power subwoofer. It has all the right features for that price point. Love it

Good product, prompt shipment. Excellent tech support.

I have an older Infinity 12" powered sub that it's internal amplifier stopped working. This little Fosi amp I am now using to replace the broken one. Sound and output of the sub is a great pairing for this sub and reasonable cost compared to a new plate amp. I was suprised how well it controlls the 12" sub with no distortion at typical listening levels.

When the plate amp went out on my old JBL E250P subwoofer (12" ported) I first considered a new Express Parts plate amp, but that would have required major butchery of the cabinet. Then I found out about mini-amps and read great things about Fosi. I was skeptical that a small amp could power a fairly large subwoofer. But after looking at the Fosi web cite I decided to give the M03 a shot. When I played the opening couple minutes of Oppeheimer (bomb blast) I knew I had made the right choice. The walls shook and I had goose bumps. My only nit--I wish the little amp had auto turn on and timed turn off.

Wasn't sure what to expect with this little amp, but it really surprised. Using it to power a 8in Yamaha 6ohm passive sub, it put out impressive base that was really well controlled. The crossover worked a treat and I used the volume to set a 'master' gain for the sub as the Fosi ZA3 commanded the system volume.
Overall this was a surprise package in a small system. Driving an 18" in a club maybe not, but in a moderate room with a reasonable passive sub really really good, clean tight base at impressive volumes!
Really my only quibble is the form factor, its really tight for realestate on the back, my interconnects were large (overkill for the set up) and the speaker binding posts are small, I used banana plugs as my stub fingers would struggle to get wires in there!
(note: I have not used this amp in a full range configuration)

Sounds great in sub and full frequency range. Amp sounds clean and is barely warm when running at medium to high power, I am thoroughly impressed.

The power for the size is unbelievable, it is compact but still has enough power to blow most bookshelf speakers. Amp feels solid and well-built with metal knobs. The speaker terminals accept banna plugs and speaker wire which is a nice touch.

One thing to note is that the low pass filter has quite a shallow roll off and you can still hear the muddy lower end of vocals even when set to the lowest setting, I don't find this an issue but just something to be aware of.

dead quiet, cannot hear any distortion, runs cool, ~ideal.

I replaced an Audiosource plate amp with this. The Audisource specs claim 130 watts in bridged mode but my passive subwoofer sounds much better with the M03 despite of the 200W rating being wishful thiunking, esp. with
the power brick it ships with. Consider this amp disposable if you end po not liking it. In that case, you have to pay return shipping to China, which is probably more than the price of the AMP. That is, if you can even get a hold of anybody at Fosi, whihc is , IMO a long shot. i wrote to support complaining about the super-optimistic power rating, nobody ever got back to me, In any case, i actually like the product, it works well for my application. I wish Fosi had some power supply options at the checkout, similar to how they sell the V3. If fthey had a 200W (useable) RMS version, now that woudl be an awesome product