Music / Audio Coming from Circuit Board - LM1875

Thread Starter


Joined Oct 7, 2015
Hey Guys,
So I built the single supply circuit from the datasheet and it works great around 20V. Playing around I connected it to a subwoofer which also works well. Crazy thing though ... connected to that subwoofer and turning the volume on the mp3 player to about 90% I can hear a tweeter kick on. I don't have one connected though. Turning the volume up the "tweeter" gets louder. I realized the sound was coming from the box which the amplifier board is mounted in. The closer I got to the thing I better I could hear it and it was actually the music I was playing coming out of the circuit itself. Sort of like a record and needle. Is it the capacitors I used? The resistors? Cheap knockoff 1875's?

I know I'm not crazy. ... well that really has nothing to do with it.... I know for sure 100% there was audio / music coming directory from the circuit board.

What's going on here?

Thanks, John