ZK-MT21 2.1 Channel Bluetooth Audio Power Amplifier Board 50W×2+100W with Treble and Bass Control for DIY Bluetooth Speaker Home Theater

I'm more impressed with this one over the larger 36v $36 one of a different brand I was using that cooling fan crapped out. This one sounds better more dynamic and seems to have as much power at 24v also I had to unplug the 3.5mm jack to use the Bluetooth this one you can just link to it even while using the jack as input and it was half the price and no fan to crap out. I'm using for my tv I boxed in the stud cavity's in the wall under my tv and cut in a 6.5" component set and an 8" subwoofer, it's pretty sweet, I also used PVC pipe to install a port into the subwoofer cavity I had to replace the sheetrock with plywood and mud it in like drywall also the sheetrock couldn't support the pressure good even with a wood ring glued on.

I'm actually surprised that this works as well as it does. I hooked it up to the speakers in an old Samsung TV soundbar and subwoofer. I usually connect via Bluetooth from my laptop. It sounds much better than anything this cheap has a right to sound. Everything functions, the Bluetooth is reliable. I can't figure out if this is the amp, but I have to keep turning down the subwoofer, probably because the speaker I hooked it up to is cheap. Otherwise, it's loud and clear.

Tiny, lightweight, powerful, and very affordable. Dialing in the bass to fit the mains is awesome. Two issues to solve however. It is so lightweight that eight wires attached at the rear will pull the amp off the shelf if not careful. If laid flat, it is difficult to grip and turn the pots. Ziptied to a vesa mount I had works great for me.

I have a couple of these. Bluetooth sounds better than using the cord. Use an appropriately powerful DC laptop brick or anything similar if you want the biggest sound. The one connected to my PC uses a 200w 20v DC brick to drive 4 speakers (2L and 2R in parallel) plus 2x 12in subs (also in parallel). It will shake things off the walls in my house. You won't believe the performance from such a cheap device. Pros: Easy to assemble, wire, and connect power. Bluetooth setup is simple. With the right power and speakers/sub, your neighbors will think there's an earthquake. Cons: Slight hiss if you leave the main volume knob turned up to max with nothing playing. If you're listening to something with pauses at low volume, it may not play the next spoken syllable or noise. This does not happen at medium volume or if the movie you are watching has birds chirping etc in the background. It's almost as if it goes to sleep for a fraction of a second.

For 20 bucks, this is great. I am powering a small subwoofer in my car, and it is able to push a good amount of power. The sub output does NOT have a frequency filter attached to it, so you can hear vocals in the sub, and it can mess up the frequency response, I recommend buying a low-pass filter for the sub-out

Easy to put together and has good shielding which makes for good sound quality. Some reviews didn’t like that it didn’t come with a pre wired power supply, that was advantageous for my project. I was able to easily wire it up to an adapter for the 18v ryobi one battery of which I have several of. Paired with a 60w subwoofer and two 8w speakers it sounds incredible. The limitations are on how much the bass makes the pack rattle. I particularly like how I can control the speakers and bass volumes independently. Fit inside my pack in the battery opening perfectly for easy access to volume control when not wearing the pack. The amount of sound upgrade for the price I paid is phenomenal. When I get a chance I’ll include a video of it coming to life

I bought this amp to replace a different similar amp that got damaged last week. I had it running a down fired subwoofer, and 2 full range speakers....all connected to my 65" TV. Long story short....I needed to replace it quickly so I could host the Canelo - Crawford fight. This amp was cheaper in price than the one it replaced but that's the only less thing about it. This one blows the old one out of the water. I'm impressed. Sound quality is superior. Note to anyone looking at these little amps ....get the 24V power supply not the 12V. Trust me.

I am powering this with my cars cigarette lighter 12V source and it is able to drive my four door speakers pretty well. It’s also very small and doesn’t generate a lot of heat. I also was able to use the sub output to send a signal to my large amp and sub so all in all you can’t beat the sound quality for a car stereo system on a budget. I’ve also been running it for around half a year now without any reliability issues.