20 Watt Audio Amplifier

This is an amplifier based on a National Semiconductor LM1875 that Bdale and Robert built to use playing around with an electric pickup on Bdale's violin. The ultimate objective is to have a modest effects chain with amp and speaker that Robert can use when playing music with his friends. We chose to start by building a high-quality amplifier.

LM1875

This part family came to Bdale's attention for other reasons, and the apparent simplicity with which a 20 watt amplifier could be built with the LM1875 made it seem like a good choice as a starting point. Samples were obtained, and the first prototype wired up using the split supply example application circuit in the data sheet just worked... and worked brilliantly!

Artifacts

A schematic for this circuit based on the data sheet reference design is in the hw/audio repository at git.gag.com.