Fosi Audio M04 Subwoofer Amplifier for Home Theater Mono Channel Digital Class D Integrated Power Amp for Passive Speakers Subwoofer

The Fosi M04 Subwoofer Amplifier was purchased as part of a computer speaker system in which the original amplifier "died of old age." The speakers were still good so it made no sense to dispose of them. Since it is not being used in a home theater system, I cannot speak to the full 100 watt output capability. My original computer speaker system (Logitech) is a 5.1 system with the amp inside the subwoofer box. I purchased a six channel amp for the surround speakers and this Fosi 04 amp for the subwoofer. All works well together. Listening to pipe organ music, which can put out some big bass sounds, the amp provides the bass that I need. (I do have a good audio system for music.Amazon has the "frequently returned" warning for this item. That's probably because people order without understanding what they need, not because the product is inferior. It produces lows from 20Hz. The item was packaged very well with foam and an attractive box, with a factory seal. I would place this in the excellent category of quality and price. (It's not junk) and has an 18 month warranty. Of course I have decades of experience building electronic devices and knew what I wanted for the purpose and budget

I purchased this to power passive the sub woofer on a Panasonic 3-speaker system I picked up at Goodwill. Great little unit, and powers the sub just fine. It is small, inconspicuous and easy to connect. Plenty of power for my office setup, easy to use and adjust quality and output levels to go along with my listening choices. This unit meets my needs for the speakers I have, and I am not disappointed.

5 stars if they supplied the larger power brick. I bought this because I have another I purchased to replace a blown sub amp. Seeing it is operable in full range mode and always wanting to try mono-blocks I felt this was the cheap way to do it and honestly it was worth it.

Easy to wire and the frequency and volume adjustments work well with good control over the levels. I'm using it to power an old subwoofer that the original receiver died on and the replacement receiver does not have a sub output built in. It brought the old sub back to life, even better than original.

I paired this amp with a Blaupunkt 10" svc sub for my home theater set up and wow... I am amazed at how well this amp pushes the sub. Lows are very low and a low that you feel in your chest. 100% thumbs up

I needed an amplifier for a passive subwoofer that came with a Kenwood HTIB and the receiver died. I was skeptical that this would work, but for the price thought I would try it. I didn't expect it to be so small, but it feels like a quality product. Using this in a bedroom system with an older Denon receiver. I connected the amp using a Y cable from the Denon Subwoofer output and turned the frequency knob all the way up. I ran Audyssey setup and it works great. Bass sounds good and not boomy. Very pleased so far great product.

Hold on to your seat, adding a sub woofer to your entertainment system adds a whole new level of enjoyment for your listening pleasure .This little sub woofer amplifier will deliver those low rumble earth quake and thunder sounds, great for watching movies, or listening to music...

There are a lot of negative reviews about this little preamplifier. I'd like to say something positive. I have lived without a subwoofer since my old RCA amp died a few years ago. I put a nice Sony in its place, but the existing subwoofer (a passive unpowered one) didn't work. I had other projects to do, so I just sort of forgot about it. Last week, I did some troubleshooting and discovered that the subwoofer output on my Sony amp is for an active powered one. So, I looked on Amazon for a nice, inexpensive solution. I found this little preamp and ordered it, and it got here the next day. I had forgotten how much I missed that '.1' of my '5.1' system. Now we have to see if it is made well enough to last for several years. Granted, I've only taken it for a single 'test drive' (The Dark Knight BluRay) but I couldn't be any happier.