The pentode was superior to a triode as an output valve; it could deliver much more power to the load for the same plate supply and required considerably less drive. 6.0 volt directly heated cathode.

There is a mistake in the inscription on the display block: it is grid 2, the screen grid, which is connected to the side terminal. The suppressor is internally connected to the centre of the filament.
The 4 pin base with side terminal arrangement allowed the user to enjoy the extra sensitivity and output power of a pentode by replacing a triode output valve with this valve by simply plugging it in and connecting the side contact to the output valve's plate supply.

Physical Description

Internal structure of an output pentode with a horizontal electrode structure with its bulb largely removed. American style 4 pin (UX) base with side terminal mounted on display block.

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