1920s Mullard PM3 Radio Triode Valve In Its Original Box

This amazing collectible is a late 1920s Mullard PM3 Radio Triode Valve In Its Original Box; where PM stands for Philips-Mullard. A nice display item for the office or radio shack!

It is over 90 years old, has never been used and hasn't been tested. As a piece of radio history made by Mullard Radio Valve Co. Ltd, Nightingale Lane, Balham, London, it is being sold as a collectible for display only. According to The History of the British Radio Valve to 1940, the valve was introduced in 1926.

This is a late 1920s version of both valve and box. It has its original paper label with the warning "THERE IS PRACTICALLY NO GLOW FROM THIS FILAMENT" and information about the filament voltage and current, and maximum anode voltage. An early owner has handwritten some test data on the paper label in 1931 and 1933. It also comes with its technical leaflet.

The cardboard box, without the cut out in the lid for the valve pins, is intact with scuffs and blemishes commensurate with age and storage. The colours have faded but are still legible.

Original Specification:

• Brand: Mullard Radio Valve Co.Ltd etched on the side in white with the series no. D218
• Type: Universal Vacuum Triode
• Marked with the BBC logo on the side
• Base: 4-Pin B4 with tubular pins with two slots
• Filament: 
• Maximum Voltage 4 Volts
• Current ~0.075 amps (NB: The current was reduced to from 0.1 to 0.075 amps in the late 1920s versions) 
• Anode Voltage 150 Volts
• For Detection, High or Low Frequency Amplification

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