The Type 43, is an audio output pentode that is designed for use in receivers with a series heater chain. It is electrically identical to the IO based 25A6. The valve is rated for use in low power single ended output stages.
Here we have the E variant where the third grid is internally connected to the control grid. In the Type 43 the suppressor grid is connected to the cathode - usual practice.
We have not, as yet, found the specific reason for this variant but the operation is not quite the same as the 43.
The Ken-Rad name on the base cap.
Top view showing the radiator attached to the copper supports of the control grid.
The three wire grids with central cathode tube and outer anode.
The classic envelope is 44 mm in diameter and, excluding the UX6 base pins, is 104 mm tall.
References: Data-sheet, 1040 & 1043. Type 43E was first introduced in 1937. See also1937 adverts.
