Noisy LM386 based audio amplifier
October 30, 2009
Inspired by this post from Salvage, I ordered a couple of gameDR Smack Talk for the XBOX units. The volume is way too low to drive a speaker directly, so I need an audio amplifier.
That led me to this post from Calculon320 on building an amplifier with an LM386. I breadboarded the audio amp, and it definitely amplified. However it also added a lot of noise. It could be cleaning it all up on a perf board would fix some of that, but it is very noticable.
I tried a few variations (20, 50, and 200 gain, with and without bass boost) from the applications examples on the LM386 datasheet. Essentially the same results. A bit less noise with less gain, but that is to be expected. Maybe it is not so much noise as distortion.
So, anyone have any thoughts on cleaning up the signal?
Oh, I just had another thought. I'm driving the output from the Smack Talk's headphone jack. There's another connector that's designed to connect to the XBOX 360 controller. That might be more like a line out. Perhaps I'd have better luck amplifying that cleanly.