Cracking noise with MAX9744 amp from Adafruit


I'm using a MAX9744 amp from Adafruit but I am getting some cracking noises. For the speakers I am using 2x Dayton Audio ND65-8. The power supply is a 12v 3A one from a different project. What could be causing this noise?

  • MisterMel

Does that happen with nothing connected to the input? If you have a volume control, does it happen with the volume control turned-down? Does it only happen when you are playing sound?

If it's happening with no input, it's probably coming from the power supply. Or the amplifier is defective (unlikely). If it's happening only with an input connected then it's obviously coming from the source.

There is almost always some "hiss" from an amplifier that you can hear with the volume/gain turned-up or with your ear close to the speaker. And, sometimes you'll get power-line hum. "Crackling" is more unusual but noise is a common problem in audio circuits.

Thanks for your reply!

I actually found out that the cause was a bad smoothing capacitor. Once I'd replaced it most of the noise already disappeared. For testing I used my phone as an audio source, but with a different source all the noise disappeared.

I'll leave this post here in case other people have the same issue.