Trouble with Adafruit MAX98357 I2S Class-D Mono Amp


Hey there,

I setup my Adafruit MAX98357 I2S Class-D Mono Amp according to the Documentation( on my Raspberry pi zero running raspbian stretch lite.

I tried both the automated script setup and the manual instructions.

I got to the point where speaker-test -c2 command outputs some sound when it runs the “Right Speaker” test, however no sound is played on the “Left Speaker” test.
I measured the voltage on SD and it’s about 0.4V.

Also no other tool produces any sound at all, i tried aplay with different params and lots of different input files (mono, stereo, difference rate), but I don’t get any sound.
I also tried the recommended mpg123, but same here: No sound.

What else could I do? Anything I could have missed?


Hopefully there will be an answer to your post over on the Adafruit forums soon, but otherwise- how is the Amp connected up, and could there be a short between the SD_MODE pin (which selects L/R or L+R/2) that’s causing only the right channel to be output?


Thanks for your reply! I thought the same about the SD_MODE pin. However the voltage measured from SD and GND seems to be in the range for stereo-mix (~0,4V), so I guess this should be fine?