The Magnaphone

Left: The first page of an article on the Magnaphone: 1912 A very wordy introduction to the idea. Copy must have been in short supply for this issue. The article is woefully short on technical detail, but we learn that one transmitting table (turntable) could drive one hundred subscriber lines. Having a single start switch is not going to keep ten turntables in 'absolute synchronisation' but why should it matter if different groups of one hundred listeners are not accurately synchronised? If you were putting out some sort of schedule, eg 'Air on a G string' at 3:00pm a simultaneous start would be a good idea. But 'absolute synchronisation' seems both pointless and impossible. Source: Popular Electricity, Dec 1912

Left: The second page of the Magnaphone article: 1912 At top left is the reference to water-cooled gramophone pickups, though they are described as 'transmitters'. The writer seems a bit confused because the water was for cooling, while the steam jacket on a steam engine cylinder is there to keep it hot, and so improve its efficiency. The need for cooling suggests that the gramophone pickups worked on the same principle as a carbon microphone; it would have to generate a hefty signal to drive 100 subscriber lines, and so a big current had to flow through it. The signal from the 'transmitters' was almost certainly passed through step-up transformers to match the impedance of the lines. The image is not of stunning quality. but shows five turntables with tone-arms that have a big box over the needle end and a bigger box over the pivot end. This is consistent with a carbon-mic type pickup. On the nearest turntable it is just possible to see what look like two rubber hoses running into the tone-arm, presumably carrying the colling water; this must have imposed seriou side-loads on the needle. There is a Wikipedia page on the system, which it calls the Tel-Musici system; no technical information is given. Where that name came from is currently unknown; it does not appear in the Popular Electricity article, and Googling has so far yielded nothing. The Wikipedia page says that 'Magnaphone' was actually the name given to the special loudspeakers used by subscribers. Source: Popular Electricity, Dec 1912

Left: The end of the Magnaphone article: 1912 The man behind the system was George R Webb. He died in the 1918 influenza pandemic. Source: Popular Electricity, Dec 1912

Left: The Tel-musici music room in Wilmington, Delaware: 1909 There is a row of turntables on the right, but no details are visible. Source: Telephony magazine for 18 December 1909, p700. Article "Distributing Music Over Telephone Lines".

Left: The Tel-musici music room in Wilmington, Delaware: 1909 This is the switching system for connecting subscribers to the appropriate turntable. Note the horn loudspeaker above the switchboard. Source: Telephony magazine for 18 December 1909, p700. Article "Distributing Music Over Telephone Lines".

Left: Tel-musici installation in a subscriber's home: 1909 This poor quality image unfortunately reveals very little. There is a horn like that of a gramophone resting on a table in the foreground; at the narrow end is a small black box which is presumably the loudspeaker. Source: Telephony magazine for 18 December 1909, p700. Article "Distributing Music Over Telephone Lines".

Left: Magnaphone train announcing system: 1913 This brief article describes the use of the Magnaphone loudspeaker for announcing the arrival of trains in noisy stations. The thing with the small horn is a water-cooled carbon microphone; two light-coloured rubber tubes convey the cooling water (note the hand valve at the bottom of the microphone stand) and a black cable connects to the black box with a big lamp on top of it. Water-cooled carbon microphones were often used in early radio broadcast transmitters. Not all the text is legible, but it appears the lamp gave some indication that the microphone was working. Source: Technical World Magazine magazine for 1913

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