Here’s a simple guitar amp that is USB powered. It only has gain control and nothing else. The amp is based on LM386 IC and can only give up to around 200mW when powered via USB. But you can get as much as 700mW when powering it with 9V and using an 8 ohm speaker. There is no volume or tone controls to make the circuit simple but I am planning to to design a USB powered guitar amp with tone controls in the future. But for now, here is the simple version.
Schematic
The schematic is simple and only has gain control. Enough for practicing alone in your room. LM386’s minimum supply voltage is 4-5V so it can be powered via USB. If you want more power, you can power it with a 9V battery or adapter.
PCB Layout
as always, the PCB layout is simple and easy to build for DIY hobbyist out there. You can download the PCB eagle file on the download page. You can opt to change the parts especially the phone jack, it is only the available 6mm phone jack on the eagle library. There are many library out there that is better but I am a little lazy to download it for now. 🙂
Downloads: