Why does a 47µF capacitor reduce noise in my LM386 amplifier?

[miroku]

hi guys,
i'm doing the testing amplifier for my DIY project,
and i using LM386 IC, i found that is a lot of noise at the output.
i saw an example putting a capacitor at the output to reduce the noise, it work!
the value of capacitor is 47uF. it not work well for other value capacitor.
But i not sure why behaviors like that? help please...

 

[berkeman]

hi guys,
i'm doing the testing amplifier for my DIY project,
and i using LM386 IC, i found that is a lot of noise at the output.
i saw an example putting a capacitor at the output to reduce the noise, it work!
the value of capacitor is 47uF. it not work well for other value capacitor.
But i not sure why behaviors like that? help please...

The LM386 is not an opamp. It is a power amp, and you do not connect feedback around it like it was an opamp. Download the datasheet from National Semiconductor's website to see how it should be used.

 

[Pumblechook]

Needs a zobell (spelling?) network.