how to make a simple amplifier for speakers, Simple amplifier using 3 transistors - YouTube
50W DIY Hi-Fi Audio Amplifier with Protection Circuitry - Gadgetronicx
How to Build Your Own Mini Altoids Guitar Amp for About $5 « Mad Science :: WonderHowTo
Build Your Own Amplifier
How to Make Your Own Speakers: 12 Steps (with Pictures) - wikiHow
Amazon.com: CYOEST DIY Bluetooth Speaker Box Kit Electronic Sound Amplifier - Build Your Own Portable Wood Case Bluetooth Speaker Sound - Science Experiment and STEM Learning for Kids, Teens and Adults : Electronics