This is a miniature 0.7W amplifier with adjustable bass boost, gain, and volume controls. Uses 1/8" (3.5mm) headphone jacks on the input and output. Powered by USB or 9v (4-12 VDC, max of 15 VDC). I designed it to use film capacitors and Nichicon audio grade electrolytic capacitors wherever possible in order to preserve the signal and reduce noise. An isolated power supply such as a battery is...
A breadboard-compatible dual non-inverter audio amp built around an opamp.
Exposes most of its internals on pins for more versatility (variable gain, simple filter, ...). Some parts are optional.
Can be stacked to create a mixer with 1 board per stereo channel and 1 board for a master volume.