ALL CREDIT FOR THIS SCHEMATIC AND AMP GO TO OSGELD OVER AT INSTRUCTABLES, who said I could share his amp over here. It's a simple audio amp, can operate between 4-12 volts. Only takes four parts, all obtainable at radio shack for under $10, or be scavenged easily from other electronics:
220 uf 16v capacitor
0.1 uf ceramic cap
(LINKS TO CHEAP PARTS)2x 10k Potentiometers http://cgi.ebay.com/2pcs-10K-B-Type-Lin ... 4aa213b90d20x 0.1 uf Cermaic Capacitors http://cgi.ebay.com/20-pcs-0-1uF-50Vdc- ... 27b328b27320x 220 uf 16v Electrolytic Capacitors http://cgi.ebay.com/20-pcs-220uF-16V-El ... 27b329719a5x LM386 ICs http://cgi.ebay.com/5-pcs-LM386-LM386L- ... 5ad47a6a3bhttp://i636.photobucket.com/albums/uu90/zeturi/easylm386.jpg
That is how everything connects. If you take a look at osgeld's instructable
, you'll see that he has a very compact arrangement for the parts.
If you want to know, gain is 20 with this schematic. If you want, connect a 10uf capacitor between pins 1 and 8, with the negative leg towards pin eight. This will give the amp a 200 gain. I tried this, but I found that it made sounds way too staticy and distorted. Without it, it still sounds good.
Enjoy your small, cheap audio amp.