DIY PCL82 Tube Amplifier, Single-Ended

This DIY single-ended tube audio amplifier project leverages a hybrid approach by combining classic thermionic valve technology with modern solid-state power regulation. At the heart of the system is the PCL82 vacuum tube, a compact dual-section device containing both a triode for voltage amplification and a pentode for power output. An incoming audio signal is first routed through a 100K potentiometer, which acts as a manual volume control by attenuating the signal level before it reaches the triode grid. Once amplified by the triode stage, the signal drives the pentode section of the PCL82 to supply the necessary current for driving a loudspeaker. Because traditional tube amplifiers typically require heavy, expensive multi-tap mains transformers to generate high anode voltages, this design modernizes the power architecture by utilizing two dedicated DC-DC boost converters powered by a standard 12V DC input. One boost converter steps the 12V supply up to approximately 230V DC to provide the high-voltage plate (anode) supply required for the PCL82 tube to operate correctly. The second DC-DC boost converter provides the required lower voltage rail. Finally, an audio output transformer rated at 5K/4R matches the high impedance output of the PCL82 pentode to the low impedance of standard 4-ohm speakers, ensuring efficient power transfer and galvanic isolation.