The Minifon P55 pocket-size magnetic-wire recorder

(manufactured in Germany and marketed in the United

Kingdom by EMI) is a notable example of miniaturization in

the recording field. The recorder provides up to 5 hours

continuous recording/playback; a choice of two recording

speeds (9.1 in. and 4.55 in./second) is provided and the

ratio of forward to re-wind speed is 1:6. The motor

operates from 6-12 volt D.C. sources, and the layer-built

12-volt dry battery has an approximate life of 10-15

hours; alternatively, the Minifon P55 may be operated from

a miniature accumulator (capacity 12-15 hours), or a

transformer-rectifier (110/220 volts A.C.). The dimensions

of the recorder are 1 9/16 in. x 3 15/16 in. x 6 11/16

in.; the weight, including batteries, is 2 lb.



(Source: E. Molloy, general editor, "Radio and Television

Engineers' Reference Book," 1954, George Newnes Ltd.

(pages 46-65, 46-66) via Dead Media)