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Wednesday, August 18, 2010

Mini Amp (LM386)

I decided to build my own mini amp to well amplify my previously constructed cigar box guitar. After searching the internet, I decided to build the amp around National Semiconductor's LM386 low voltage audio power amplifier (data sheet).

My Finished mini amp (new cigar box guitar build sneak peak!).


I followed the below schematic from Make's CrackerBoxAmp. It is a fairly simple amp and one can purchase everything from radio-shack. Their schematic is also similar to the circuits in the data sheet and other schematic on the internet. The only thing I changed was that I power the circuit with 12v instead of 9v. It is possible to power this circuit with a 9v battery.
I scavenged a 4" 4 ohm speaker from a surround sound speaker and the grill to protect the speaker. I made the box out of 1/4" oak.

I also used a piece of sheet metal to hold the power switch, master volume pot, 1/4" input and LED.

 I also shielded the circuit board with metal tape.

Assembled box with 4" speaker.

Assembled circuit and wires.

Power input (left) and 1/8" audio jack for connecting an ipod (right).

It actually sounds pretty good!