Adafruit audio FX mini and 2.5W amplifier
If you look in the datasheet of the PAM8302 you can see that pin 1 is called SD but note that the pin is actually called S̅D̅ &lt;= Note the overbar

The overbar means that the pin is active low, also see the drawing on page 2. You need to make S̅D̅ = 0 for shutdown.

On the PCB containing the PAM8302 SD is actually marked wrongly. I do not see a transistor on the PCB (which could invert the signal and make "SD" correct) so the SD goes straight into the chip, making it a not(SD).

So yes, you need to invert the ACT signal.

The simplest way to do that is by using an NPN or a NMOS, like so:







simulate this circuit &ndash; Schematic created using CircuitLab

You could also use a CMOS logic chip with gates that can also work as an inverter like the HEF4011.