2A3-40

About the 2A3-40

The JJ Electronic 2A3-40 is a high-performance AF triode with a 4-pin ceramic base, designed primarily for Hi-Fi audio applications. It features a directly heated cathode and a power rating of 40 watts, which is significantly higher than typical 2A3 tubes, providing greater headroom and robustness. The tube operates with a heater voltage of 2.5V at 2.5A, and typical electrical characteristics include a plate voltage (Ua) of 250V, grid voltage (Ug) of -45V, plate current (Ia) of 60mA, and transconductance (S) of 5.25 mA/V. Compared to the 300B tube, the 2A3-40 offers more detailed sound with better tone separation and a larger active cathode surface due to its heater center tap design, resulting in improved sound quality. It is a mono-plate tube with a robust build, capable of handling up to 450V on the plate and dissipating 40W of power, making it suitable for demanding audio amplifier designs. The tube is noted for its dynamic and punchy sound character, often described as having better body, image density, and midrange presence than comparable tubes.