RedRoo is a high-quality, single-ended, 5 Watt per-channel, Class-A valve amplifier that can power loudspeakers or low-impedance headphones. It can also be configured as a 10 Watt mono-block.
The circuit is a no-compromise design using a two-stage Constant Current Draw Amplifier (CCDA) as the input stage. The CCDA draws a constant current from the power supply, and provides a low impedance drive to the output stage which (we believe) produces a cleaner sound if amplifier is pushed hard into overload.
The circuit also uses DC heaters and a unique power supply design that produces no buzz or hum and extremely low background noise. The output transformers are unusually large for the power level, which ensures strong and accurate base reproduction with delicate high frequency details. You can try different types of valves and each output stage can be configured as either a triode, pentode, or ultra-linear stage. There is also provision on the PC board for an optional Bluetooth input module, if streaming from your smartphone or laptop is your thing.
The selection of quality components and the professionally designed 2mm thick double-sided printed circuit board leads to trouble-free construction. With a little patience and skill you will have a superb sounding amplifier you can be proud of, at a fraction the cost of a similar commercially built amp.
The PC Board, and the HV power supply module are available from this website. Supply details are provided for suitable output transformers.
Please let us know what you think.