The ECL80 is a triode, output pentode for audio use. The heater at 6.3 Volts and 300 mA makes this valve suitable for equipment with mains transformers and heater chains across the domestic mains.
The ECL80 is a low power device with the triode feeding the pentode for a compact single end audio stage. However, one maker (mullard) describe the ECL80 as primarily designed for use in television receivers (VHF 405 line models) with the triode as a frame blocking oscillator and the pentode as a frame output valve.
The pentode is at the bottom of the envelope with the triode mounted above on the common cathode tube.
A close-up view of the triode.
looking through the holes in the pentode anode it can be seen to have three wire grids at right angles to the triode axis.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 59 mm tall.
References: Datasheet & 1040. Type ECL80 was first introduced in 1950.