How to Build a Basic USB Powered Amplifier

Buy a LM386, this chip has been around for ever, is cheap, plentiful and the recommended supply voltage is 4-12VDC.

With the notch on the chip facing you and pointing up, the pinout from left to right, top to bottom is:

LM386 Pinout

Pin 1 : Gain Pin 8 : Gain
Pin 2 : Input – Pin 7 : Bypass
Pin 3 : Input + Pin 6 – Voltage Supply
Pin 4 – Ground Pin 5 – Voltage Out

To get some sort of sound going, you’ll need the following:

  • 10ohm resistor
  • 10kOhm resistor
  • 0.05uF capacitor
  • 250uF capacitor

All of the above information can be found on the Texas Instruments LM386 datasheet, very handy!