JUST loud enough to make anyone in the same office ask me to turn down the Judas Priest. It drives some cheap little speakers in a Snap-On toolbox sound bar. I have no clue if the speakers are 4 or 8 ohm or what. Pre-existing circuitry had been introduced to 120VAC through aux input jack by their owner. Notice the little 3.5mm stereo audio input jack? Yeah, perfect for raspberry pi. A generic laptop power supply (NOT DELL or apple.) provides 19vdc to power this little guy. This thing was designed well and built well and it works great...so long as you aren't really expecting more than 5W/ch. That's right...5 (five). NOT 50. Can you honestly complain, for this money? Look at it! Do you really expect some 100W out of it? Ever touch a 100W light bulb? Hey, it works, it was perfect for my needs, it was cheap, I really like it. Yes, there is the occasional hiss noise when powered and not driven. All of our sound needs do not require audiophile-level stuff. All the input/output options and powering options make this thing immediately take care of any generic sound need - without fuss or bother at all.

This review is for the 100W+100W 2 Channel amplifier. This system is basically two complete mono TPA3116 amplifiers on the same board. The two chips are setup at the maximum gain (36db) and this produces a significant hissing noise in my speakers. I replaced the resistors according to the TPA3116 data sheet to produce the minimum gain of 20db. At this level the hissing is completely gone and the amplifier performs excellent!!!!

One thing to note is that the two TPA3116 chips are not synced together, they are both configured as Master and the SYNC leads have no connection on the board so it could not be reconfigured even if you wanted to. I haven't heard one where the channels are synced together so I'm not sure exactly how it would sound they were.

Here's the exact link to the one I purchased:
Yeeco 100W+100W 2 Channel Digital Power Audio Sereo Amplifier Board, DC 12-24V Car Stereo AMP Module for Vehicle Auto Computer Audio System DIY Speakers with Volume Knob Double Chips Heatsink

This works as advertised. It's a great little amp for creating your own system on the cheap. I paired this with an Alexa device (Amazon Echo) via the aux output on the echo and the input on the card. This gave me an amp-ed echo. I ran it to two ceiling speakers ($38 each) and a wall sub ($40). The levels and quality are good considering the inexpensive speakers I used. But now the echo plays music in the whole room on better than her tiny speaker. I plan to do this in multiple rooms and thus when I have Alexa play everywhere, it's a better whole house sound. Note: as it states, it doesn't come with a power supply. I found a 5-pack of 12v (transformer) plugs/cords here on amazon for under $20. (also found one for 50 cents at my local thrift store). I wouldn't have minded finding an 18-24v to power this, but the 12v really does well.

**Edit**
Ok, so I did order two more of these, and both of them came defective with one channel not working. Such a disappointment. When it works, this is a 5-star in my opinion. But since I've now bought 3 and only 1 worked, I'm lowering it to 2 stars. If you're patient and don't mind the return process, this can be a great option. But getting defective products stinks!

This is a review for the 2x50w + 100w board. It is excellent, especially for its small size. Almost no noise when nothing is playing. The knobs are all volume knobs. One for the left and right volume, one for the bass volume, and one for overall volume. This allows you to adjust the relative volume of your sub and satellite speakers to correct for different efficiency levels. My only complaint is that it does not reject RF noise very well. I tested this with two Bluetooth boards. Both boards worked fine with another amp, but with this amp one of the Bluetooth boards generated a lot of RF noise and the amp did not reject it. The amp picked up the RF noise even when the BT module was not connected to the inputs. So, it was purely RF noise and not on the signal lines. The other BT board did not generate any RF noise and sounds amazing. My testing was done with 5s lithium ion batteries for the amp at about 18v and an isolated 12v power supply for the BT boards.

Quality Control of this product is horrible. Impossible to terminate the speaker cables because the output terminals were installed backwards. Termination ports are facing the opposite side. Pictures attached.