Marconi Crystal Receiver With Valve, by Marconi Company, London, c. 1916

Marconi Crystal Receiver With Valve, based on a Marconi Crystal Receiver Type 16, with one crystal detector replaced by a four-pin valve-holder. With potentiometer knobs and battery terminals marked 'Crystal' and 'Valve', additional copper switch on side and later knob on top. With Bakelite capacitance dial (scale 0-10,SHORT), Inner & Outer Sheath copper terminals, copper alloy telephone terminals, Jigger Switch knob, and Intensifier knob (scale -80,0,80), and nine copper alloy terminals, upon ebonite surface on teak case. This example appears to have been a factory made receiver using a Type 16 chassis, although the usual Aerial Tuning Inductance was never fitted; the company name and serial number (115806) took its place, now partially obscured by the later, unmarked rotating knob.