Here’s a simple amplifier you can build. it uses the popular TDA2030 amplifier IC. It can deliver up to 35W which is good enough for room audio. It is in bridged mode meaning it is using 2 IC with the output of the other IC is 180° out of phase.
Here’s a simple PCB layout that I made using a single layer PCB so it will be easy for DIY home made PCB. It is done using kicad software as usual. Take note that I used kicad version 5. I am not sure if you will have problem using an older version but I had encountered a problem loading my older files. It is not loading the 3d models. The simple solution was to delete all the footprint library settings and then load it again.
Using kicad 3d renderer.
You can download the kicad files in the download section here.