MP3 Trigger background noise

Hi,

i have a Qwiic MP3 Trigger and it has some backround noise wehen it is not playing a sound file.

The electrecity source is a bench top powersupply with 12V and a adjustable stepdown power regulator to 3.3V.

At the other side is a 20W class D amplifier connected vie 3,5mm audio jack.

I tried the following things:

  • played musik from a nother source to the amplifier / no noise

  • taped off the earth connection on the power supply / no result

  • changed from the amplifier board to a battery powerd bluethoothspeaker via 3,5mm audio jack / no result

  • changed the 3,5mm audio jack to a soldert connection between the boards / no result

  • changed the power source to a 12V Battery / no result

  • powerd the MP3 trigger direcly with 3,3V from the benchtop powersupply and the amplifier with a 12V Battery / no result

Can somebody help me with my Problem?

Can you provide a picture of your setup?

Are you able to add a decoupling capacitor on the power lines going to the MP3 trigger? https://learn.sparkfun.com/tutorials/ca … n-examples