Microphone, Reiss (Reisz) carbon granule

Made by Amalgamated Wireless Australasia Pty Ltd (AWA) in Australia, Oceania, c. 1930.

The AWA microphone while significant as a rare example of a high quality Australian manufactured microphone of the period c 1930, is important primarily as one of the microphones used at the official launch of the Sydney Harbour Bridge on 19 March 1932 and because it has been signed by ten of the dignitaries participating in the opening.

Of the ten the best known today are Jack Lang New South Wales premier, Sir Philip Game New South Wales Governor and JJC Bradfield New South Wales Chief Enginee...

Summary

2007/147/1
The microphone consists of a rectangular marble block which has been hollowed out and filled with carbon granules through a threaded hole in the top. The hole is sealed by a metal plug. The front face of the microphone consists of a mica film which is secured by an ebonite frame. This in turn is covered by a fine wire mesh which is held in place by a metal escutcheon fastened by six screws. There is a leather strap fixed with screws at each side which acts as a handle. On the back face of the microphone are two large terminals set at the middle line of the back. The microphone is a transverse current microphone and differs from other carbon microphone in the current bias flows in a direction perpendicular to the pressure than in the rather than parallel to the direction of pressure.

Dimensions

100 mm
100 mm
75 mm

Production

The microphone was made by AWA in Australia, c. 1930.

The 'Reisz' or 'Cullinan' type microphones were made in Australia by radio engineers who often built their own from various published construction details. In the late 1920s AWA started to manufacturing commercially after acquiring a BBC Marconi Reisz model from Marconi. They had the marble blocks made by a local monument mason and made the carbon granules in the AWA Laboratory.
Amalgamated Wireless Australasia Pty Ltd (AWA) c. 1930

History

This particular microphone was one of three microphones used at the opening ceremony for the Sydney Harbour Bridge in 1932. It has been signed by a number of local dignitaries who officiated at the event. It is believed that this microphone is the middle one of the three which can be seen in photographs of the official opening. The microphone was supplied by the AWA, who were responsible for organising the broadcast of the ceremony. They managed to devise a setup in which a single microphone (which ever of the three was being used) would service all the broadcast radio stations, the public address system, as well as 'talkie' films and gramophone recordings.

The microphone became one of a collection of microphones owned by Philip Geeves who was announcing for AWA on the day of the opening. It is assumed that he organised for the signatures to be collected and kept the microphone. He later became President of the OTC veterans group and donated his material to the OTC historical collection on his retirement.

To some collectors it has been considered to have been lost- the Museum has been approached by a number of people wondering if we might have it even wishing to see the Reisz type that we have to check that it doesn't have the signatures. While there has been an online article stating that the microphone was at the Telecom Museum in Ashfield, that was not the case. It was found in 2005 in the OTC collection at La Perouse when that collection was being packed up to go to the Telstra Museum which is now at Bankstown. OTC became part of Telstra in 1993 which means that title for the microphone would have passed to them then.
Lang, John Thomas (Jack) 1932

Source

Gift of Telstra Corporation Limited, 2007
23 October, 2007

Cite this Object

Microphone, Reiss (Reisz) carbon granule 2017, Museum of Applied Arts & Sciences, accessed 28 June 2017, <https://ma.as/365306>
{{cite web |url=https://ma.as/365306 |title=Microphone, Reiss (Reisz) carbon granule |author=Museum of Applied Arts & Sciences |access-date=28 June 2017 |publisher=Museum of Applied Arts & Sciences, Australia}}
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