Sensibly equivalent¶ to:
The 1F4 is a battery audio output valve. It is identical electrically to the 1F5G, the difference being that the 1F5G is on a IO base.
The anode load for use in single ended circuits is 16,000 Ohms. A cathode resistor value is not given.
The base looks more like a B5 than a UX5 - something is wrong. All the data-sheets point to the UX5 base for the 1F4.
Thanks to Mark Mallison for sending the images.
The classic envelope is 43 mm in diameter and, excluding the UX5 base pins, is 96 mm tall.
References: Datasheet & 1043. Type 1F4 was first introduced in 1936.
Absolute Maximum Operating Conditions¶
Updated October 13, 2019. shape:classic construction:pinch type:pentode age:1930.1940 base:ux5 heater:2.0v pins:8 pin:1.- pin:2.f+ pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.f- pin:8.-