This was a simple experiment to built a 1 watt amplifier and speakers in order to gain some experience to ultimately build my amplifier version 2.0 (which, due to cost will take a while to finish). I mostly used parts I had on hand.
Speakers
The speakers are cheap 8 Ohm speakers that are found everywhere. These came from old computer cases. For the enclosure I used cardboard boxes that held passives I ordered from Jameco. I cut a circular hole in the bottom of the box and hotglued the speaker to the box. The flap is on the back and allows access to the inside. These sound like crap but the enclosure does provide some resonence that makes it louder.
Amplifier
This is a simple 1 watt (my calculation) amp that uses the LM386. For stereo you simply duplicate the circuit for each channel. After alot of work I fit two channels in the case but but but realized too late that by mirroring the layout the pins on the LM386 change. I tried to hack it to work but ended up pulling everything for the second channel so now it's only mono.
The circuit I used is from http://www.techlib.com/electronics/audioamps.html.
Part list (for mono)
| Part | Description | Digikey # | Quant | Unit Price |
|---|---|---|---|---|
| 1nF capacitor | BC1013CT-ND | 1 | $0.08 |
|
| 1μF capacitor | ECA-1HM010 | 1 | $0.15 |
|
| 10μF capacitor | P807-ND | 3 | $0.14 |
|
| 100μF capacitor | P970-ND | 1 | $0.18 |
|
| 10kΩ potentiometer | P3M3103-ND | 1 | $1.08 |
|
| 10Ω resister | 10H-ND | 1 | $0.05 |
|
| LM386 opamp | LM386N-3-ND | 1 | $0.94 |
|
| 8Ω speaker | GF0573-ND | 1 | $4.60 |
|
| power jack | CP-5-ND | 1 | $1.95 |
|
| stereo audio jack | CP-2505-ND | 2 | $0.93 |
|
| switch | SW116-ND | 1 | $0.91 |
|
| Enclosure | HM113-ND | 1 | $6.49 |
|
| Total | $17.78 |