Maker's Name: 
Amplifiers Ltd, England
Where made: 
circa 1925?
25 × 25 × 6 cm

Housed in a wooden box lined with blue fabric in the lid. On the facade, there are dials for the 'tuning' of the circuit to the desired station and two plugs by means of which extra capacitance may be added. Incoming modulated radio waves set up voltages across the antenna which is connected to a tuning circuit which consists of a capacitor and variable inductor 'tuned' to filter out all but the frequency of a desired station. Contact between a metal wire and galena crystal rectifies the output signal to allow a set of headphones to respond to the audio frequency components of the modulation. In spite of the name of the manufacturer, there is no amplifier involved, and the energy to drive the headphones comes out of the received signal.This was one of a series of U.K. crystal sets approved by the BBC. Tuning was by coil taps, there being no variable capacitor. It operated on the Medium Wave (Broadcast band), but could be operated on Long-wave by removing the shorting bar and plugging in an additional inductor.
A.H. et al.