2A3 Single Plate

About the 2A3 Single Plate

The RCA 2A3 Single Plate is a directly heated triode vacuum tube designed for use in the power-output stage of AC operated receivers. It features a single plate (mono-plate) structure, which many audiophiles consider the best sounding variant of the 2A3 tubes. It operates with a filament voltage of 2.5V and filament current of 2.5A. The tube is known for its exceptionally linear plate curves, low plate impedance (~800 ohms), and high transconductance, making it ideal for single-ended Class A amplifiers delivering around 3.5 watts of output power. The single plate design contributes to a sweet, musical, and detailed sound, favored especially in high-fidelity audio applications with well-designed horn loudspeakers. The 2A3 Single Plate tube was originally manufactured by RCA in the USA and is now considered a vintage, collectible item with New Old Stock (NOS) examples highly sought after. It is no longer manufactured by RCA but remains in demand among tube audio enthusiasts and DIY amplifier builders.