Adafruit stereo 3 7w class d audio amplifier adafruit 987 p the adafruit stereo 3 7w class d audio amplifier features agc automatic gain control and up to 89 efficiency making it ideal for battery powered projects optional onboard jumper pins supplied let you control the gain quickly and easily though it can be controlled by signals from off the board there s also a shutdown pin for each channel 1 0 micro f capacitors on the input channels make them fully differential the r and l