TDA2822M Stereo Amplifier
This project uses the great little TDA2822M stereo amplifier IC, which is an 8 pin DIL package capable of delivering 1W + 1W of power into an 8 ohm load. That doesn't sound very much and there's nothing special about the circuit which is based on the manufacturers datasheet, but the sound quality is actually pretty good (and surprisingly loud) when used with a decent pair of hifi speakers. The schematic diagram and veroboard layout are shown below
Note: The TDA2822M has 8 pins and the TDA2822 (without the 'M') has 14 pins... Beware!
A general purpose plastic project box with removable front and rear panels was used to house the amplifier. Loudspeaker connection is via a 4 way barriered terminal strip with power and audio sockets being 2.1mm coax and 3.5mm jack respectively. You can use whatever you prefer. An old offcut of veroboad was used as a crude bus to route audio from the input jack, through the volume control into the amplifier. I found this much easier than mucking about with screened cable, and as the amplifier has a relatively low input sensitivity, hum isn't a problem. A safety fuse was also added in series with the supply to protect against component failure
The finished amplifier