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HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Gramophone. History of invention and production
Directory / The history of technology, technology, objects around us A gramophone is a device for reproducing sound from a gramophone record.
Not least among the remarkable technological achievements of the 1857th century is the invention of sound recording. The first sound recording device was created in XNUMX by Leon Scott. The principle of operation of his phonoautograph was very simple: a needle, which transmitted the vibrations of a sound diaphragm, drew a curve on the surface of a rotating cylinder covered with a layer of soot. Sound waves in this device received, as it were, a visible image, but nothing more - it is clear that it was impossible to reproduce the sound recorded on soot. The next important step along this path was taken by the famous American inventor Edison. In 1877, Edison created the first "talking machine" - the phonograph, which made it possible not only to record, but also to reproduce sound.
Edison spoke of his invention as follows: “Once, when I was still working on improving the telephone, I somehow sang over the diaphragm of the telephone, to which a steel needle was soldered. Due to the trembling of the records, the needle pricked my finger, and this made me think. If If it were possible to record these vibrations of the needle, and then pass the needle over such a record again, why wouldn't the record speak? pass the tape with the record again under the needle, I heard, however, very weakly: "Hello, hello". Then I decided to build a device that would work clearly, and instructed my assistants, telling what I had come up with. They laughed at me " . The principle of the phonograph was in general the same as that of the telephone. Sound waves were brought to a plate of very thin glass or mica with the help of a speaking tube, and a cutter attached to it was recorded on a rapidly rotating shaft covered with tin foil. Traces were obtained on the foil, the shape of which corresponded to the vibrations of the plate and, consequently, to the sound waves incident on it. This strip of sheet tin could be used to produce the same sounds on the same instrument. With uniform rotation of the strip, the cutter attached to the plate passed along the groove made by him earlier. As a result of this, the plate was driven by the chisel into the same vibrations that it had previously transmitted to it under the influence of the voice and sound instrument, and began to sound like the membrane of a telephone. Thus the phonograph reproduced every conversation, singing and whistling.
The first Edison devices, created in 1877, were still very imperfect. They wheezed, nasalized, exaggerated some sounds, did not reproduce others at all, and in general, they looked more like parrots than loudspeakers of human speech. Their other drawback was that the sound could be distinguished only by putting the ear to the diaphragm. This was largely due to the fact that the roller did not move smoothly enough on the surface, which could not be made completely smooth. The needle, moving from one recess to another, experienced its own oscillations, transmitted in the form of strong noises. Edison worked hard to improve the phonograph. He encountered especially many problems with the reproduction of the sound "s", which did not want to be recorded. He himself later recalled: “For seven months I worked almost 18-20 hours a day on one word“ spice ”. petia, petia, petia. It was possible to go crazy! But I did not lose heart and persistently continued my work until I overcame the difficulties. How difficult my task was, you will understand if I say that the traces obtained on the cylinder at the beginning of the word , were no more than one millionth of an inch deep! It is easy to make amazing discoveries, but the difficulty lies in perfecting them so that they are of practical value.
After many experiments, a more or less suitable material for the rollers was found - an alloy of wax and some vegetable resins (Edison kept this recipe a secret). In 1878 he founded a special firm for the production of phonographs. At the same time, all the newspapers were widely advertised for his invention. It was assured that the phonograph could be used for dictating letters, publishing audio books, playing music, learning foreign languages, recording telephone messages, and many other purposes. But, alas, none of these promises was fulfilled even in 1889, when a new phonograph was constructed, which did not have many of the shortcomings of the former. The principle of its operation remains the same. The wax cylinder W was driven by an electric motor in the box K with a very smooth and even running. Regulator G controlled the rotation speed of the cylinder (125 rpm) by turning the resistors on and off. Lever A, supporting the speaking tube and record, rested on a sled. This sledge was moved along the guide bar F by means of a threaded nut M, which rested on the shaft of the main screw, which had fine threads and formed the axis of the cylinder C. This thread was an exemplary work of mechanics and had one screw strokes per inch. Two levers A and B served to push the nut off the main rod. Phonograph records were made of very thin glass; of these, one had a sharp chisel for recording the vibrations of a plate on a wax cylinder, the other had a blunt chisel for reproduction. The third, somewhat stronger record, was equipped with a small sharp chisel in order to regrind the worn-out wax cylinders and thus use them for new recordings. A trumpet with a bell was used to amplify the sound.
The writing part was a round diaphragm embedded in a metal ring, the space above which was closed by a lid with a bell. If you speak into this bell, then the sound waves reach the diaphragm and set it in oscillatory motion. From below, a thin writing point was attached to the middle of the diaphragm, with the help of which a groove was cut out on the wax shell of the drum, more or less deep, according to the fluctuations of the diaphragm. The diaphragm with its accessories was supported on a lever, which was attached to a sliding device, and together with the latter moved when the drum rotated from right to left. In order for this movement to occur in accordance with the rotation of the drum, a second lever was fixed on the sliding device, which rested on the screw spindle with its end, leaning on it with part of the nut.
Thus, when the spindle moved, the sliding device moved, and since the spindle was connected by an endless cord to the drum shaft, the sliding device and, together with it, the pin moved in accordance with its rotation, and the pin cut a helical line on the wax mass. As long as the diaphragm did not oscillate, the pin carved a groove of uniform depth, but as soon as the diaphragm began to oscillate under the influence of sound waves, the depth of the groove constantly decreased, then increased. This wave-like strip was then used to set in motion another similar diaphragm, to which a pin sliding along the groove was attached. However, the new improved phonograph did not receive wide practical application. In addition to the high price, practical imperfections prevented its distribution. The roller could not contain much information and filled up in a few minutes. More or less significant correspondence required a large number of rollers. After several listenings, the copy was destroyed. The transfer of the apparatus itself was far from perfect. In addition, it was impossible to get copies from the wax roller. Each record was unique and with damage to the roller was lost forever. All these shortcomings were successfully overcome by Emil Berliner, who in 1887 took out a patent for another sound recording device - the gramophone. Although the principle of the gramophone and phonograph was the same, the gramophone had a number of significant differences, which ensured its wide distribution. First of all, the needle in Berliner's recording apparatus was parallel to the plane of the diaphragm and drew winding lines (rather than furrows, like Edison's). In addition, instead of a bulky and uncomfortable roller, Berliner chose a round plate.
The recording took place as follows. A polished zinc disk intended for sound recording was mounted on a large-diameter disk with a rim. A solution of wax in gasoline was poured on top of it. The disc-bath received rotation from the handle through a friction gear, and a system of gears and a lead screw connected the rotation of the disc with the radial movement of the recording membrane mounted on the rack. This achieved the movement of the recording device along a spiral line. When the gasoline evaporated, a very thin layer of wax was left on the disc, and the disc was ready to be recorded. Berliner produced a sound groove in almost the same way as Edison, using a recording membrane equipped with a tube with a small horn and transmitting its vibrations to an iridium tip.
The main advantage of recording according to the Berliner method was that copies could be easily obtained from the disc. To do this, the recorded disc was first of all immersed in an aqueous solution of chromic acid. Where the surface of the disk was covered with wax, the acid had no effect on it. Only in the sound grooves, because the recording point cut the wax all the way to the surface of the disc, did the zinc dissolve under the action of the acid. In this case, the sound groove was etched to a depth of about 0 mm. The disk was then washed and the wax removed. In this form, it could already serve to reproduce sound, but in fact it was only the original for the manufacture of copper galvanic copies. The principle of electroforming was discovered in 1838 by the Russian electrical engineer Jacobi. Electrolytes have already been mentioned above - liquids that conduct electric current through themselves. A feature of electrolytes is that in solutions (or melts) their molecules decompose into positive and negative ions. Thanks to this, electrolysis becomes possible - a chemical reaction that proceeds under the influence of an electric current. For electrolysis, metal or carbon rods are placed in the bath, which are connected to a constant current source. (The electrode connected to the negative pole of the battery is called the cathode, and the electrode connected to the positive pole is called the anode.) The electric current in the electrolyte represents the process of movement of ions to the electrodes. Positively charged ions move towards the cathode, while negatively charged ions move towards the anode. On the electrodes, a reaction of neutralization of ions takes place, which, giving up extra electrons or receiving the missing ones, turn into atoms and molecules. For example, each copper ion receives two missing electrons at the cathode and is deposited on it in the form of metallic copper. In this case, the deposit gives an accurate relief image of the cathode. This last property is precisely used in electroforming. A copy (matrix) is taken from the copied objects, representing their reverse negative image. The copy is then suspended as a cathode (negative pole) in a plating bath. The metal from which the copy was made is taken as the anode (positive pole). The bath solution must contain ions of the same metal. Berliner acted in exactly the same way - he immersed a zinc disk in a bath with a solution of copper salt and connected the negative pole of the battery to it. In the process of electrolysis, a layer of copper 3-4 mm thick was deposited on the disk, exactly repeating all the details of the disk, but with a reverse relief (that is, tubercles were obtained in place of the grooves, but exactly repeating all their twists). Then the resulting copper copy was separated from the zinc disc. It served as a matrix with which it was possible to press disks-plates from some plastic material. In the beginning, celluloid, ebonite, all kinds of wax masses, and the like were used for this purpose. The very first gramophone record in history was made by Berliner in 1888 from celluloid. Gramophone records, which went on sale in the early 90s, were made of ebonite. Both of these materials were not suitable for the intended purpose, since they were poorly pressed and therefore did not accurately reproduce the relief of the matrix. Having done many experiments, Berliner in 1896 created a special shellac mass (it included shellac - a resin of organic origin, heavy spar, ash and some other substances), which then remained for many decades the main material for making records.
The records were played on a special device - a gramophone. The main part of the sound-picking device here was a mica plate, coupled by a lever with a clamp into which interchangeable steel needles were inserted. Rubber gaskets were placed between the clamp and the membrane body. Initially, the gramophone was driven by hand, and then began to be installed on a box with a clockwork. Both the recording device and Berliner's first gramophones were very imperfect. Hiss, crackle and distortion were their constant companions. Nevertheless, this invention was a huge commercial success - in just ten years, gramophones spread throughout the world and penetrated into all sectors of society. By 1901, about four million records had already been released. Phonographs could not compete with the creation of Berliner, and Edison had to curtail their production. Author: Ryzhov K.V.
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