Record album, ‘Records for use in conjunction with the Marconiphone Manual on Electrical Interference’, containing four 12-inch double-sided 78 rpm records, each labelled ‘Electrical interference with broadcast reception’, Parts 1 to 8, catalogue numbers MC.1 to MC.4, matrix numbers 32-4362 to 32-4369, together with (in pocket inside rear cover) booklet, ‘Marconiphone Manual Electrical Interference with Broadcast Reception’, made by the Marconiphone Co Ltd (part of Electric and Musical Industries Ltd, or EMI), Hayes, Middlesex, England, 1930 – 1940.

When broadcasting began in the 1920s clear reception of programmes needed to be free of radio-frequency interference, but it was discovered that electrical equipment and machinery of different kinds created interference that could affect the enjoyment of listening significantly.

To help radio set repairers identify the causes of interference, the Marconiphone Company (a subsidiary of EMI) prepared a set of records illustrating various kinds of interference, linked to a special printed ‘Marconiphone Manual’ that described ways of alleviating the problems. The records and manual, put up in a conventional record album, were made available only to radio-set dealers and repairers. It is likely that few such sets survive today, but they give a vivid idea of the ways in which listeners’ enjoyment of broadcast programmes could be impaired.