The X24, is a battery triode heptode mixer / local oscillator for use as a frequency changer in superhet receivers. It was supplied in both metallised and clear envelope versions.
The Osram brand label.
The design is as two separate electrode structures mounted side by side.
A closer view.
The top mica of the mixer showing the twin oxide coated filaments, signal grid connected to the top cap and internally the wire grids.
The top mica of the triode oscillator. A single inverted V filament attached to a helical spring and held by a hook.
The thin glass tube envelope is 41 mm in diameter, and excluding the B7 base pins is 103 mm tall.
Reference: Data-sheet. Type X24 was first introduced in 1939. See also1939 adverts.
