Raspberry Pi’s combination of small size, versatility, and affordability has led to a number of interesting projects. The Raspberry Pi Tube Amp is just the latest. This add-on is compatible with all 40-pin versions of the Pi, and adds a 24-bit DAC, single 12AU7 tube gain stage, and a solid state Class A output that can drive headphones ranging 32 to 200 Ohms with ease. A gain select switch sets the output to the optimum level for your listening device, so the only thing you really need to worry about is what sort of case you want to build.
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