You most likely know that LM317 IC is applied as an practical provide regulator, but did you know it can be applied as an audio amplifier? This is a Low power Amplifier LM317 Simple Audio Amplifier Circuit a audio designed with LM317 that offers a optimum probable 1W audio strength.
LM317 Simple Audio Amplifier Circuit Diagrams :
|LM317 Simple Audio Amplifier Circuits|
Utilization a amazing heatsink for the LM317 IC and modify the 5K various resistor so that you have 4.5V on 10Ω resistor (or LM317 pin 2, Vout).