Tetrode (usually called a screen-grid valve in its day) designed for use as a radio frequency (RF) amplifier in AC mains powered equipment. The use of a screen grid between the control grid and the plate reduced the grid-plate capacitance and permitted high gain at radio frequencies without stability problems. 2.5 volt indirectly heated cathode.

Vox was a brand used by the Munder Electrical Company.

Physical Description

Internal structure of an early indirectly heated tetrode with its bulb removed and part of its internal screen and anode removed also to show its construction. American style 5 pin (UY) base with top cap. Mounted on display block with a sectioned example of a similar valve.

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