The P3580 is an audio output pentode for use in universal mains sets ie with or without mains transformers from a time when DC mains still existed.
Made by the Austrian company Triotron it was produced with the Ct8 base and the B7 for the British market.
The output is 4 Watts with a 320Ω cathode resistor and an anode load of 4,500Ω
The classic envelope is 49 mm in diameter, and excluding the B7 base pins is 113 mm tall.
References: 1043. Type P3580 was first introduced in 1936. See also 1936 adverts.
Absolute Maximum Operating Conditions¶
Updated January 05, 2022.