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This is a very basic small mains powered
stereo amplifier. Output power is probably about two watts
per channel. Not much, but quite enough to drive small
passive speakers for casual listening at low volume levels. The amplifier board is from some cheap powered pc-speaker. Originally it had an external ac-adapter, but I hate those wall wart things. So I built a simple ac power supply with a regulator circuit to prevent hum and noise. There is no hiss from the speakers when you switch power on - great! I made a box using wood and aluminum. As you can see, there is not much inside. Front panel has power switch, volume pot and power on -led. Back side has phono connectors for line input and a terminal block to connect speakers. Power supply schematic:  |
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