Version: Dec. 8, 2003

Unknown maker

Backward earphone



This is an electric reproducer made out of an Edison C reproducer and a Dominion Electro Home earphone. One of the holes where the earphone was attached to the headband can be seen in the picture above. The active parts of the earphone were an iron membrane and an electromagnet. When the electromagnet was fed an audio frequency AC input, it would produce sound. But it can also be run backwards - by making the membrane vibrate it would produce an AC output.

The solution in this case was to enlarge the central hole in the Edison C reproducer and solder a hook to the centre of the membrane to which the C reproducer's sapphire, holder and hook could be attached. These are now missing, as is the cable leading to the amplifier. Dominion Electro was a Canadian company located in Kitchener, Ontario.

This ingenious adaption forms part of the collection of Jean-Paul Agnard, who provided the pictures.

Christer Hamp, 2003


From the left: what remains of the Edison reproducer, with the hole enlarged; the membrane from the earphone with traces of the soldering at its centre; the earphone casing, with the electromagnets.

If you know who built this reproducer, please write: Visit Jean-Paul Agnard's pages:
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