1920s Mullard PM3 Radio Triode Valve In Its Original Box

This amazing collectible is a 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 nearly 100 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 an early version of both valve and box. It has its original paper label with the warning "THERE IS NO GLOW FROM THIS FILAMENT" and information about the filament voltage and current, and maximum anode voltage. 

The early version cardboard box, without the cut out in the lid,  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
• Type: Universal Vacuum Triode
• Marked with the BBC logo and DT06
• Base: 4-Pin B4 with a single slot in each pin (split pin)
• Filament: 
• Voltage 3.0-3.7 Volts
• Current ~0.1 amps (NB: The current was reduced to 0.075 amps in later versions) 
• Anode Voltage 50-100 Volts
• For Detection, High or Low Frequency Amplification

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