1933 __ Textophone
‣ Comment : Kurt Stille develops a vastly improved magnetic recorder using better steel wire and vacuum tube amplifiers [than the Blattnerphone]. This machine, called a Textophone, was widely used by the Gestapo during WWII. (Compiled from various sources) — In 1878, Oberlin Smith, after a trip to Edison's Labs proposed the idea of recording telephone signals onto a length of steel piano wire. This was published in Electrical World, Sep. 8, 1888. Between about 1898 and 1900, Danish inventor Valdemar Poulsen developed and patented the"Telegraphone," a telephone recorder that recorded on steel wire. The Telegraphone (emphasis on the second syllable) was the first machine that could record sound magnetically. Later Poulsen was to demonstrate a steel tape recorder and a machine that would record magnetically on a steel disk. These were marketed as alternatives to phonograph- dictating machines, or telephone recording machines. The Telegraphone produced in quantity used steel wire. It was made in at least two versions. One was manufactured by Poulsen's workers in Denmark, and another by the American Telegraphone Company in Wheeling, West Virginia and later in Springfield, Massachusetts. The Telegraphone was not a successful. It demonstrated that a wire recorder could be used for applications such as office dictation and telephone recording. European companies attempted to market improved wire recorders for dictating and telephone recording in the 1920s. These used the new technology of electronics. They employed the vacuum-tube electronic amplifiers. These machines could record weak telephone signals and play them back them with greater volume than with the Telegraphone. Two of these of these European machines were the "Textophone" and the "Dailygraph." The Dailygraph was created by German inventor Curt (or Kurt) Stille, a leading promoter of magnetic recording in the 1920s. It was used as a dictation machine. It had a special telephone for input and output, and foot pedals were used by a typist to start and stop the recording while transcribing. (Compiled from various sources) — Karl Bauer, to whom [Stille] had sold a license to produce dictating and telephone-recording equipment, organized the Echophone Company for the production of the Dailygraph, which was a combination dictating machine and telephone recorder. The Dailygraph was the first magazine machine, which is to say that both the supply and take-up reels constituted a single unit detachable from the machine. This scheme conferred a distinct advantage, since the reels could be removed from the machine at any time without the necessity of first rewinding the entire spool. The Dailygraph also contained an automatic-volume-control device, which was necessitated by the unpredictable level of long-distance telephone conversations of that day. This was a long time before the introduction of stabilized feedback repeater amplifiers, and the signal level was likely to vary as much as ten to one from one conversation to another. The use of these machines for telephone recording had some success, and permission was obtained from a number of the European telephone companies-many of which were government-owned-to connect these machines to their lines. In this connection, it might be pointed out that magnetic-recording machines were the first instruments which had ever made it possible to record a telephone conversation directly, because at the time of their invention, they were the only machines that could record sound by means of an electrical current. The Telegraphone had antedated by considerable time the development of the present-day electrical record cutter. Like the old Telegraphone, the Dailygraph employed a wire speed of 7 ft. per sec., but its magazine held sufficient wire to record for a full hour. This characteristic was in no small measure due to a reduction of the wire diameter from 0.01 to 0.008 inch, for a given volume of wire the total recording time is approximately inversely proportional to the square of the diameter of the wire. A number of different models were manufactured, and the sales literature of the company listed the price of the least expensive unit as 2,250 reichsmarks. The exchange value of this sum at the time equaled nearly $600. Despite the fact that the Dailygraph worked very well and a large numher of machines were sold, it had several weaknesses, and Bauer, being somelung of a salesman himself, sold the Echophone Company to the Internarional Telephone and Telegraph Company in 1932. They in turn passed it on to the C. Lorenz Company, an associated company and one of the biggest German communication firms. Lorenz completely redesigned the Dailygraph and marketed it under the name of Textophone. Both the names Textophone and Dailygraph, it might be added, had been chosen to help the sale of the machines on the international market. The Textophone represented a re-al improvement over the Dailygraph both from the standpoint of reliability of operation and the ease with which it could be mass-produced. The vacuumtube amplifier that it contained was also considerably better than that of its predecessor. The Textophone was placed on the market in 1933, about the time Hitler came to power. The Nazis needed all the recording equipment they could get, and the Gestapo bought huge numbers of Textophones for the German government. The market was not entirely a domestic one, however, for they were sold all over Europe, several hundred installations having been made in Switzerland alone. The Lorenz Company also developed a steel-tape recorder, which it marketed under the name of Stahltonmaschine. It likewise had considerable success and in 1935 was adopted by the German Broadcasting Company, which used it extensively in mobile pickups. One other German development in magnetic recording, which is of considerable interest, was the Magnetophone. Pileumer, in 1927, had conducted numerous experiments with magnetic-recording mediums consisting of paper or plastic tapes coated with powdered magnetic materials. The grain size of the materials was rather large, and the resulting tapes somewhat resembled sandpaper. However, in 1931 he managed to get the Ailgemeine Electrizitäts Gesellschaft (A.E.G.) to take over this work. Thereafter, A.E.G., together with I. G. Farben, undertook the development of his idea; I. G. Farben continued the development of the tapes, and A.E.G. developed the associated electronic and mechanical apparatus. The Magnetophone had been designed as a dictating machine, but it was considerably inferior to the Textophone and Stahltonmaschine. It was first demonstrated in 1935 at the German Annual Radio Exposition in Berlin, and despite its mediocre performance, it was something of a hit, and for a very simple reason. Steel tape such as was used in the Stahltonmaschine in 1935 was so expensive as to make 1 minute's recording cost about $1, while the coated tape employed by the Magnetophone cost only 15 cents per mm. Not only did this represent a saving in the cost of the material, che nature of the plastic tape made it possible to wind it on a single reel, instead of on the bulky magazines that the Textophone required, and thus effected another substontial saving. (Semi J. Begun, “History of Magnetic Recording”, 1949)
‣ French comment : En 1933, une version améliorée de la machine de Stille (Blattnerphone) est mise sur le marché par la Société Lorenz. La police nazie, la Gestapo, achète en quantité ces dispositifs pour espionner les conversations téléphoniques et enregistrer les interrogatoires des prisonniers. Tandis que la radio américaine ne diffuse que des émissions en direct, les radios européennes émettent des programmes enregistrés sur support magnétique. (Nicolas Vicente, “Mémoires Magnétiques”) — Avec l'apparition des amplificateurs dans les années 20, l'idée [du Télégraphone de Poulsen] est reprise en Allemagne par Kurt Stille qui fabrique en 1928 le Textophone, enregistrant sur un fil d'acier, et en 1929, par Ludwig Blattner qui propose le premier enregistreur sur bande d'acier, le Blattnerphone, utilisé par la BBC pour ses émissions rediffusées (mais il pèse une tonne et il faut 1km et demi de bande pour 1/2 heure d'enregistrement). En 1934, AEG et BASF fabriquent le premier Magnetophon enregistrant sur bande magnétique souple et le premier enregistrement est réalisé dans la salle de concert de BASF le 19 novembre 1936 par le London Philharmonic Orchestra dirigé par Thomas Beecham. (Compiled from various sources) — La paternité du premier enregistreur magnétique revient au Danois Valdemar Poulsen qui fit breveter son invention en 1898. A cette époque, ce procédé n’eut pas beaucoup de succès mais on sait aujourd’hui que cette invention a été à la base de tous les magnétophones construits par la suite. Le son était enregistré sur un fil d’acier passant devant un électroaimant relié à un microphone. L’électroaimant magnétisait plus ou moins le fil selon les variations du son capté par le microphone. Pour reproduire le son enregistré, on faisait passer le fil d’acier une seconde fois devant l’aimant, ce qui induisait des petits courants électriques. Après amplification le son original était ainsi restitué. Le principe de la machine de Poulsen fut repris dans le Blattnerphone, machine anglaise créée par Ludwig Blattner en 1929. Le support d’enregistrement était un ruban d’acier. Outre l’enregistrement magnétique du son cinématographique, le Blattnerphone, fut aussi utilsé dès 1932 par la BBC pour retransmettre le discours de Noël du roi George V. Par la suite, le procédé fut amélioré par Kurt Stille qui utilisa un acier de meilleure qualité et des amplificateurs à vide. Une nouvelle version de cet appareil appelé Textophone fut commercialisée en 1933. L’enregistrement sur fil d’acier reste un mode de reproduction sonore très particulier qui sera surtout employé pour l’enregistrement de la voix. (Compiled from various sources)
‣ Source : Begun, S. J. (1949), “Magnetic Recording”, New York: Rinehart & Company, 1949.
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