This was a little project I did becasue I did not have a headphones amp. It is a very small amplifier. Its sound quality is mediocre. Not that it is horrible, just don't expect it to sound amazing. I also did not really put time into it improve it. Probably if I had put a cap across the output and ground or something like that I may have gotten better results. The amp has alot of white noise. But it does serve the purpose I built it for, and can be built for pretty cheap.
This project was one that I had a difficult time finding something suitable on the internet. Eventually I ended up just using the circuit out of the spec sheet for the ic I used.
This is the layout the board I made click the pictures for a pdf (that is scaled correctly)
I am not going to bother calling out all of the item values, they are in the spec sheet
nor am I going to call out the switch and the potentiometer, they are standard at radiosmack, basically
the smallest ones they carry. The middle of the power swith has a jumper that goes to pin 6 on the ic. The board cannot fit in the altoids case if you put the output capacitor on there, so I put that in between the output
and the board, connected to the top right pad in the above picture. So basically solder + side the 250uf Cap onto the board, nd the other end on the speaker. Again let me say that all of these parts can easily be purchased at a local store. The pictures should be good enough that you can identify them.
I used radiosmack 1/8" jacks, A small radiosmack thumbwheel 10k audio potentiometer, a small dpdt radiosmack switch, and of course the altoids box. It is from altiods gum. In total the project maybe cost 15$, but I did have all the circuit board making stuff and components hanging around.
This is the spec sheet for the ic, the LM386. It can be purchased at radiosmack or for 50 cents at any other electronics store. Buy more than one you probably will break one.
This is the circuit from the spec sheet that you should use.
Perminant link http://www.thekofc.net/projects/altoidamp