I was able to have that happen to me 3 times, and never again. Ive been playing with two builds, a Pimusicbox and a raspbian with mopidy extensions and web client build. I still cannot say for sure what’s happened because I’ve ran that same speaker and tested a car audio speaker on that same I2S (pwm audio) amplifier running day and night. Not one chip on the build nor the speakers get a tiny bit hot any more. My belief is that the PiMusicBox image out of the box which OVERWRITES asound.conf every time it boots up was overwriting the correct settings I needed for converting digital audio or whatever for my setup.
I figured out how to change it in the core of PiMusicbox, it could have something to do with over heating, or maybe sending a faint noise to keep the amp on while there is no playback could of solved it. I went back and re-ran this script ’ curl -sS https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/i2samp.sh | bash ’ and said YES to enable /dev/zero so perhaps both fixing Loud Pops that start on play back or when changing songs and playing a faint sound when paused could prevent erratic spikes of voltage. IT COULD also be this 5v power supply that can supply up to 4Amps output because it has a super charge feature for my huawei phone is the culprit ( I dont plan on using it after I finish the project )
Anyways. Take that to heart. If I notice any other oddities I’ll be sure to post haha