KT66 is the designator for a beam tetrode vacuum tube introduced by Marconi-Osram Valve Co. Ltd. of Britain in 1937. The KT66 is the direct descendant of the "Harries Valve" developed by British engineer J. Owen Harries and marketed by the Hivac Co. Ltd. in 1935. Harries is believed to be the first engineer to discover the "critical distance" effect, which maximized the efficiency of a power tetrode by positioning its anode at a distance, a specific multiple of the screen grid-cathode distance; this design minimized interference of secondary emission electrons dislodged from the anode. EMI engineers Cabot Bull and Sidney Rodda improved the Harries design with a pair of beam plates, connected to the cathode, which directed the electron streams into two narrow areas and acted like a suppressor grid to deflect some secondary electrons back to the anode; the beam tetrode design was undertaken to avoid the patents which the giant Philips firm held on power pentodes in Europe. Because this overall design eliminated the "tetrode kink" in the lower parts of the tetrode's voltage-current characteristic curves, M-OV marketed this tube family as the "KT" series, standing for "kinkless tetrode".
A number of different KT tubes were marketed by M-OV. Some, but not all, were versions of existing American beam tetrode tubes or European power pentodes, such as the KT66, KT77, KT88, KT63. Although the RCA 6L6 of 1936 was the first true "beam power tube" on the market, the KT66 became equally famous, at least in Europe; the two tubes were nearly interchangeable, except that the KT66 was somewhat more rugged than the early metal 6L6. The KT66 was popular in European radios and audio amplifiers, it was the standard output tube in the classic Quad II and in the LEAK Type 15 and TL/12, both among the earliest British hi-fi amplifiers. Because of their excellent electrical characteristics and overload tolerance, KT66s are preferred by some guitar players for use in guitar amps in place of 6L6GC. However, the plate dissipation of the 6L6GC, at 30W, exceeds the KT66's 25W, adjustment of the amplifier's bias is necessary. M-OV ceased glass vacuum tube manufacturing in 1988. In 2004 original M-OV KT66 tubes, unused in original carton, sold for US$250.
As of 2012 KT66 tubes continued to be manufactured at Reflektor Saratov in Russia, JJ Electronic in Slovakia, at Liuzhou in China. Some modern Russian manufacture Sovtek KT66 tubes are 6L6GC tubes in a KT66 style bottle. While these tubes have the same pinout and minimum tolerances required of a KT66 tube, they do not have the performance characteristics of a true kinkless tetrode KT66 tube. By contrast the latest Russian manufactured tubes not only carry the same internal electrode structure as the original KT66 they have the same rugged electrical characteristics and can withstand a high voltage on grid 2 comparable to the anode voltage rating, allowing greater power output afforded by higher voltage capability when run in ultralinear connection. KT88 6L6 6CA7 / EL34 6V6 807 Barbour, Eric. "History of the 6L6" in Vacuum Tube Valley, issue 4, p. 3. Schade, O. H. "Beam Power Tubes" in Proceedings of the IRE, February 1938. Stokes, John. 70 Years of Radio Tubes and Valves. Vestal Press, NY, 1982.
Thrower, Keith. History of the British Radio Valve to 1940. MMA International, 1982, p. 59. Several tube datasheets TDSL Tube data
A triode is an electronic amplifying vacuum tube consisting of three electrodes inside an evacuated glass envelope: a heated filament or cathode, a grid, a plate. Developed from Lee De Forest's 1906 Audion, a partial vacuum tube that added a grid electrode to the thermionic diode, the triode was the first practical electronic amplifier and the ancestor of other types of vacuum tubes such as the tetrode and pentode, its invention founded the electronics age, making possible amplified radio technology and long-distance telephony. Triodes were used in consumer electronics devices such as radios and televisions until the 1970s, when transistors replaced them. Today, their main remaining use is in high-power RF amplifiers in radio transmitters and industrial RF heating devices. In recent years there has been a resurgence in demand for low power triodes due to renewed interest in tube-type audio systems by audiophiles who prefer the sound of tube-based electronics; the name "triode" was coined by British physicist William Eccles sometime around 1920, derived from the Greek τρίοδος, tríodos, from tri- and hodós meaning the place where three roads meet.
Before thermionic valves were invented, Philipp Lenard used the principle of grid control while conducting photoelectric experiments in 1902. The first vacuum tube used in radio was the thermionic diode or Fleming valve, invented by John Ambrose Fleming in 1904 as a detector for radio receivers, it was an evacuated glass bulb containing a heated filament and a plate. Triodes came about in 1906 when American engineer Lee De Forest and Austrian physicist Robert von Lieben independently patented tubes that added a third electrode, a grid, between the filament and plate to control current. Von Lieben's partially-evacuated three-element tube, patented in March 1906, contained a trace of mercury vapor and was intended to amplify weak telephone signals. Starting in October 1906 De Forest patented a number of three-element tube designs by adding an electrode to the diode, which he called Audions, intended to be used as radio detectors; the one which became the design of the triode, in which the grid was located between the filament and plate, was patented January 29, 1907.
Like the von Lieben vacuum tube, De Forest's Audions were incompletely evacuated and contained some gas at low pressure. Von Lieben's vacuum tube did not see much development due to his death 7 years after he invented it at the outbreak of World War I. De Forest's Audion did not see much use until its ability to amplify was recognized around 1912 by several researchers, who used it to build the first successful amplifying radio receivers and electronic oscillators; the many uses for amplification motivated its rapid development. By 1913 improved versions with higher vacuum were developed by Harold Arnold at American Telephone and Telegraph Company, which had purchased the rights to the Audion from De Forest, Irving Langmuir at General Electric, who named his tube the "Pliotron", These were the first vacuum tube triodes; the name "triode" appeared when it became necessary to distinguish it from other kinds of vacuum tubes with more or fewer elements. There were lengthy lawsuits between De Forest and von Lieben, De Forest and the Marconi Company, who represented John Ambrose Fleming, the inventor of the diode.
The discovery of the triode's amplifying ability in 1912 revolutionized electrical technology, creating the new field of electronics, the technology of active electrical devices. The triode was applied to many areas of communication. Triode "continuous wave" radio transmitters replaced the cumbersome inefficient "damped wave" spark gap transmitters, allowing the transmission of sound by amplitude modulation. Amplifying triode radio receivers, which had the power to drive loudspeakers, replaced weak crystal radios, which had to be listened to with earphones, allowing families to listen together; this resulted in the evolution of radio from a commercial message service to the first mass communication medium, with the beginning of radio broadcasting around 1920. Triodes made transcontinental telephone service possible. Vacuum tube triode repeaters, invented at Bell Telephone after its purchase of the Audion rights, allowed telephone calls to travel beyond the unamplified limit of about 800 miles.
The opening by Bell of the first transcontinental telephone line was celebrated 3 years on January 25, 1915. Other inventions made possible by the triode were television, public address systems, electric phonographs, talking motion pictures; the triode served as the technological base from which vacuum tubes developed, such as the tetrode and pentode, which remedied some of the shortcomings of the triode detailed below. The triode was widely used in consumer electronics such as radios and audio systems until it was replaced in the 1960s by the transistor, invented in 1947, which brought the "vacuum tube era" introduced by the triode to a close. Today triodes are used in high-power applications for which solid state semiconductor devices are unsuitable, such as radio transmitters and industrial heating equipment. However, more the triode and other vacuum tube devices have been experiencing a resurgence and comeback in high fidelity audio and musical equipment, they remain in use as vacuum fluorescent displays, which come in a variety of implementations but all are triode devices.
All triodes have a hot cathode electrode heated by a filament, which releases electrons, a flat metal plate electrode to which the electrons are att
A loudspeaker is an electroacoustic transducer. The most used type of speaker in the 2010s is the dynamic speaker, invented in 1925 by Edward W. Kellogg and Chester W. Rice; the dynamic speaker operates on the same basic principle as a dynamic microphone, but in reverse, to produce sound from an electrical signal. When an alternating current electrical audio signal is applied to its voice coil, a coil of wire suspended in a circular gap between the poles of a permanent magnet, the coil is forced to move back and forth due to Faraday's law of induction, which causes a diaphragm attached to the coil to move back and forth, pushing on the air to create sound waves. Besides this most common method, there are several alternative technologies that can be used to convert an electrical signal into sound; the sound source must be amplified or strengthened with an audio power amplifier before the signal is sent to the speaker. Speakers are housed in a speaker enclosure or speaker cabinet, a rectangular or square box made of wood or sometimes plastic.
The enclosure's materials and design play an important role in the quality of the sound. Where high fidelity reproduction of sound is required, multiple loudspeaker transducers are mounted in the same enclosure, each reproducing a part of the audible frequency range. In this case the individual speakers are referred to as "drivers" and the entire unit is called a loudspeaker. Drivers made for reproducing high audio frequencies are called tweeters, those for middle frequencies are called mid-range drivers, those for low frequencies are called woofers. Smaller loudspeakers are found in devices such as radios, portable audio players and electronic musical instruments. Larger loudspeaker systems are used for music, sound reinforcement in theatres and concerts, in public address systems; the term "loudspeaker" may refer to individual transducers or to complete speaker systems consisting of an enclosure including one or more drivers. To adequately reproduce a wide range of frequencies with coverage, most loudspeaker systems employ more than one driver for higher sound pressure level or maximum accuracy.
Individual drivers are used to reproduce different frequency ranges. The drivers are named subwoofers; the terms for different speaker drivers differ, depending on the application. In two-way systems there is no mid-range driver, so the task of reproducing the mid-range sounds falls upon the woofer and tweeter. Home stereos use the designation "tweeter" for the high frequency driver, while professional concert systems may designate them as "HF" or "highs"; when multiple drivers are used in a system, a "filter network", called a crossover, separates the incoming signal into different frequency ranges and routes them to the appropriate driver. A loudspeaker system with n separate frequency bands is described as "n-way speakers": a two-way system will have a woofer and a tweeter. Loudspeaker driver of the type pictured are termed "dynamic" to distinguish them from earlier drivers, or speakers using piezoelectric or electrostatic systems, or any of several other sorts. Johann Philipp Reis installed an electric loudspeaker in his telephone in 1861.
Alexander Graham Bell patented his first electric loudspeaker as part of his telephone in 1876, followed in 1877 by an improved version from Ernst Siemens. During this time, Thomas Edison was issued a British patent for a system using compressed air as an amplifying mechanism for his early cylinder phonographs, but he settled for the familiar metal horn driven by a membrane attached to the stylus. In 1898, Horace Short patented a design for a loudspeaker driven by compressed air. A few companies, including the Victor Talking Machine Company and Pathé, produced record players using compressed-air loudspeakers. However, these designs were limited by their poor sound quality and their inability to reproduce sound at low volume. Variants of the system were used for public address applications, more other variations have been used to test space-equipment resistance to the loud sound and vibration levels that the launching of rockets produces; the first experimental moving-coil loudspeaker was invented by Oliver Lodge in 1898.
The first practical moving-coil loudspeakers were manufactured by Danish engineer Peter L. Jensen and Edwin Pridham in 1915, in Napa, California. Like previous loudspeakers these used horns to amplify the sound produced by a small diaphragm. Jensen was denied patents. Being unsuccessful in selling their product to telephone companies, in 1915 they changed their target market to radios and public address systems, named their product Magnavox. Jensen was, for years after the invention of a part owner of The Magnavox Company; the moving-coil principle used today in speakers was patented in 1924 by Chester W. Rice and Edward W. Kellogg; the key difference between previous attempts and the patent by Rice and Kell
Public address system
A public address system is an electronic system comprising microphones, amplifiers and related equipment. It increases the apparent volume of a human voice, musical instrument, or other acoustic sound source or recorded sound or music. PA systems are used in any public venue that requires that an announcer, etc. be sufficiently audible at a distance or over a large area. Typical applications include sports stadiums, public transportation vehicles and facilities, live or recorded music venues and events. A PA system may include multiple microphones or other sound sources, a mixing console to combine and modify multiple sources, multiple amplifiers and loudspeakers for louder volume or wider distribution. Simple PA systems are used in small venues such as school auditoriums and small bars. PA systems with many speakers are used to make announcements in public and commercial buildings and locations—such as schools and passenger vessels and aircraft. Intercom systems, installed in many buildings, have both speakers throughout a building, microphones in many rooms so occupants can respond to announcements.
PA and Intercom systems are used as part of an emergency communication system. The term, sound reinforcement system means a PA system for live music or performance. In Britain any PA system is sometimes colloquially referred to as a Tannoy, after the company of that name now owned by TC Electronic Group, which supplied a great many of the PA systems used in Britain. From the Ancient Greek era to the nineteenth century, before the invention of electric loudspeakers and amplifiers, megaphone cones were used by people speaking to a large audience, to make their voice project more to a large space or group. Megaphones are portable hand-held, cone-shaped acoustic horns used to amplify a person’s voice or other sounds and direct it towards a given direction; the sound is introduced into the narrow end of the megaphone, by holding it up to the face and speaking into it. The sound projects out the wide end of the cone; the user can direct the sound by pointing the wide end of the cone in a specific direction.
In the 2010s, cheerleading is one of the few fields where a nineteenth century-style cone is still used to project the voice. The device is called “speaking-trumpet”, “bullhorn” or “loud hailer”. In 1910, the Automatic Electric Company of Chicago, Illinois a major supplier of automatic telephone switchboards, announced it had developed a loudspeaker, which it marketed under the name of the Automatic Enunciator. Company president Joseph Harris foresaw multiple potential uses, the original publicity stressed the value of the invention as a hotel public address system, allowing people in all public rooms to hear announcements. In June 1910, an initial "semi-public" demonstration was given to newspaper reporters at the Automatic Electric Company building, where a speaker's voice was transmitted to loudspeakers placed in a dozen locations "all over the building". A short time the Automatic Enunciator Company formed in Chicago order to market the new device, a series of promotional installations followed.
In August 1912 a large outdoor installation was made at a water carnival held in Chicago by the Associated Yacht and Power Boat Clubs of America. Seventy-two loudspeakers were strung in pairs at forty-foot intervals along the docks, spanning a total of one-half mile of grandstands; the system was used to announce race reports and descriptions, carry a series of speeches about "The Chicago Plan", provide music between races. In 1913, multiple units were installed throughout the Comiskey Park baseball stadium in Chicago, both to make announcements and to provide musical interludes, with Charles A. Comiskey quoted as saying: "The day of the megaphone man has passed at our park." The company set up an experimental service, called the Musolaphone, used to transmitted news and entertainment programming to home and business subscribers in south-side Chicago, but this effort was short-lived. The company continued to market the enunciators for making announcements in establishments such as hospitals, department stores and railroad stations, although the Automatic Enunciator Company was dissolved in 1926.
Peter Jensen and Edwin Pridham of Magnavox began experimenting with sound reproduction in the 1910s. Working from a laboratory in Napa, they filed the first patent for a moving coil loudspeaker in 1911. Four years in 1915, they built a dynamic loudspeaker with a 1-inch voice coil, a 3-inch corrugated diaphragm and a horn measuring 34 inches with a 22-inch aperture; the electromagnet created a flux field of 11,000 Gauss. Their first experiment used a carbon microphone; when the 12 V battery was connected to the system, they experienced one of the first examples of acoustic feedback, a unwanted effect characterized by high-pitched sounds. They placed the loudspeaker on the laboratory's roof, claims say that the amplified human voice could be heard 1 mile away. Jensen and Pridham refined the system and connected a phonograph to the loudspeaker so it could broadcast recorded music, they did this on a number of occasions, including once at the Napa laboratory, at the Panama–Pacific International Exposition, on December 24, 1915 at San Francisco City Hall alongside Mayor James Rolph.
This demonstration was official presentation of the working system, 100,000 people gathered to hear Christmas music and speeches "with absolute distinctness". The first outside broadcast was made one week again supervised by Jensen and Pridham. On December 3
Alan Dower Blumlein was an English electronics engineer, notable for his many inventions in telecommunications, sound recording, stereophonic sound and radar. He received 128 patents and was considered as one of the most significant engineers and inventors of his time, he died during World War II on 7 June 1942, aged 38, during the secret trial of an H2S airborne radar system under development, when all on board the Halifax bomber he was flying in were killed when it crashed at Welsh Bicknor in Herefordshire. Alan Dower Blumlein was born on 29 June 1903 in London, his father, Semmy Blumlein, was a German-born naturalised British subject. Semmy was the son of Joseph Blumlein, a German of Jewish descent, Philippine Hellmann, a French woman of German descent. Alan's mother, Jessie Dower, was Scottish, daughter of William Dower who went to South Africa for the London Missionary Society. Alan was christened as a Presbyterian. Alan Blumlein's future career seemed to have been determined by the age of seven, when he presented his father with an invoice for repairing the doorbell, signed "Alan Blumlein, Electrical Engineer".
His sister claimed that he could not read proficiently until he was 12. He replied "no, but I knew a lot of quadratic equations!" After leaving Highgate School in 1921, he studied at Guilds College. He joined the second year of the course, he graduated with a First-Class Honours BSc two years later. In mid-1930, Blumlein met a preparatory school teacher five years his junior. After two-and-a-half years of courtship the two were married in 1933. Lane was warned by acquaintances before the wedding that, "There was a joke amongst some of his friends, they used to call it'Blumlein-itis' or'First Class Mind', it seems that he didn't want to know anyone who didn't have a first class mind." Recording engineer Joseph B. Kaye, known as J. B. Kaye, Blumlein's closest friend and best man at the wedding, thought the couple were well matched. In 1924 Blumlein started his first job at International Western Electric, a division of the Western Electric Company; the company subsequently became International Standard Electric Corporation and later on, Standard Telephones and Cables.
During his time there, he measured the amplitude/frequency response of human ears, used the results to design the first weighting networks. In 1924 he published the first of his only two IEE papers, on high-frequency resistance measurement; this won him the IEE's Premium award for innovation. The following year he wrote a series of seven articles for Wireless World. In 1925 and 1926, Blumlein and John Percy Johns designed an improved form of loading coil which reduced loss and crosstalk in long-distance telephone lines; these were used until the end of the analogue telephony era. The same duo invented an improved form of AC measurement bridge which became known as the Blumlein Bridge and subsequently the transformer ratio arm bridge; these two inventions were the basis for Blumlein's first two patents. His inventions while working at STC resulted in another five patents, which were not awarded until after he left the company in 1929. In 1929 Blumlein resigned from STC and joined the Columbia Graphophone Company, where he reported directly to general manager Isaac Shoenberg.
His first project was to find a method of disc cutting that circumvented a Bell patent in the Western Electric moving-iron cutting head used, on which substantial royalties had to be paid. He invented the moving-coil disc cutting head, which not only got around the patent but offered improved sound quality, he led a small team. The other principal team members were Henry "Ham" Clark, their work resulted in several patents. Early in 1931, the Columbia Graphophone Company and the Gramophone Company merged and became EMI. New joint research laboratories were set up at Hayes and Blumlein was transferred there on 1 November the same year. During the early 1930s Blumlein and Herbert Holman developed a series of moving-coil microphones, which were used in EMI recording studios and by the BBC at Alexandra Palace. In June 1937, Blumlein patented the Ultra-Linear amplifier. A deceptively simple design, the circuit provided a tap on the primary winding of the output transformer to provide feedback to the second grid, which improved the amplifier's linearity.
With the tap placed at the anode end of the primary winding, the tube is connected as a triode, if the tap was at the supply end, as a pure pentode. Blumlein discovered that if the tap was placed at a distance 15–20% down from the supply end of the output transformer, the tube or valve would combine the positive features of both the triode and the pentode design. Blumlein may or may not have invented the long-tailed pair; the long-tailed pair is a form of differential amplifier, popular since the days of the vacuum tube. It is now more pervasive than as it is suitable for implementation in integrated circuit form, every operational amplifier integrated circuit contains at least one. In 1931, Blumlein invented what he now known as stereophonic sound. In early 1931, he and his wife were at the cinema; the sound reproduction systems of the early talkies only had a single set of speakers – the actor might be on one side of the screen, but the voice could come from the other. Blumlein declared to his wif
London is the capital and largest city of both England and the United Kingdom. Standing on the River Thames in the south-east of England, at the head of its 50-mile estuary leading to the North Sea, London has been a major settlement for two millennia. Londinium was founded by the Romans; the City of London, London's ancient core − an area of just 1.12 square miles and colloquially known as the Square Mile − retains boundaries that follow its medieval limits. The City of Westminster is an Inner London borough holding city status. Greater London is governed by the Mayor of the London Assembly. London is considered to be one of the world's most important global cities and has been termed the world's most powerful, most desirable, most influential, most visited, most expensive, sustainable, most investment friendly, most popular for work, the most vegetarian friendly city in the world. London exerts a considerable impact upon the arts, education, fashion, healthcare, professional services and development, tourism and transportation.
London ranks 26 out of 300 major cities for economic performance. It is one of the largest financial centres and has either the fifth or sixth largest metropolitan area GDP, it is the most-visited city as measured by international arrivals and has the busiest city airport system as measured by passenger traffic. It is the leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. London's universities form the largest concentration of higher education institutes in Europe. In 2012, London became the first city to have hosted three modern Summer Olympic Games. London has a diverse range of people and cultures, more than 300 languages are spoken in the region, its estimated mid-2016 municipal population was 8,787,892, the most populous of any city in the European Union and accounting for 13.4% of the UK population. London's urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census.
The population within the London commuter belt is the most populous in the EU with 14,040,163 inhabitants in 2016. London was the world's most populous city from c. 1831 to 1925. London contains four World Heritage Sites: the Tower of London. Other landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Paul's Cathedral, Tower Bridge, Trafalgar Square and The Shard. London has numerous museums, galleries and sporting events; these include the British Museum, National Gallery, Natural History Museum, Tate Modern, British Library and West End theatres. The London Underground is the oldest underground railway network in the world. "London" is an ancient name, attested in the first century AD in the Latinised form Londinium. Over the years, the name has attracted many mythicising explanations; the earliest attested appears in Geoffrey of Monmouth's Historia Regum Britanniae, written around 1136. This had it that the name originated from a supposed King Lud, who had taken over the city and named it Kaerlud.
Modern scientific analyses of the name must account for the origins of the different forms found in early sources Latin, Old English, Welsh, with reference to the known developments over time of sounds in those different languages. It is agreed; this was adapted into Latin as Londinium and borrowed into Old English, the ancestor-language of English. The toponymy of the Common Brythonic form is much debated. A prominent explanation was Richard Coates's 1998 argument that the name derived from pre-Celtic Old European *lowonida, meaning "river too wide to ford". Coates suggested that this was a name given to the part of the River Thames which flows through London. However, most work has accepted a Celtic origin for the name, recent studies have favoured an explanation along the lines of a Celtic derivative of a proto-Indo-European root *lendh-, combined with the Celtic suffix *-injo- or *-onjo-. Peter Schrijver has suggested, on these grounds, that the name meant'place that floods'; until 1889, the name "London" applied to the City of London, but since it has referred to the County of London and Greater London.
"London" is sometimes written informally as "LDN". In 1993, the remains of a Bronze Age bridge were found on the south foreshore, upstream of Vauxhall Bridge; this bridge either reached a now lost island in it. Two of those timbers were radiocarbon dated to between 1750 BC and 1285 BC. In 2010 the foundations of a large timber structure, dated to between 4800 BC and 4500 BC, were found on the Thames's south foreshore, downstream of Vauxhall Bridge; the function of the mesolithic structure is not known. Both structures are on the south bank. Although there is evidence of scattered Brythonic settlements in the area, the first major settlement was founded by the Romans about four years after the invasion
The phonograph is a device for the mechanical recording and reproduction of sound. In its forms, it is called a gramophone or, since the 1940s, a record player; the sound vibration waveforms are recorded as corresponding physical deviations of a spiral groove engraved, incised, or impressed into the surface of a rotating cylinder or disc, called a "record". To recreate the sound, the surface is rotated while a playback stylus traces the groove and is therefore vibrated by it faintly reproducing the recorded sound. In early acoustic phonographs, the stylus vibrated a diaphragm which produced sound waves which were coupled to the open air through a flaring horn, or directly to the listener's ears through stethoscope-type earphones; the phonograph was invented in 1877 by Thomas Edison. While other inventors had produced devices that could record sounds, Edison's phonograph was the first to be able to reproduce the recorded sound, his phonograph recorded sound onto a tinfoil sheet wrapped around a rotating cylinder.
A stylus responding to sound vibrations produced an down or hill-and-dale groove in the foil. Alexander Graham Bell's Volta Laboratory made several improvements in the 1880s and introduced the graphophone, including the use of wax-coated cardboard cylinders and a cutting stylus that moved from side to side in a zigzag groove around the record. In the 1890s, Emile Berliner initiated the transition from phonograph cylinders to flat discs with a spiral groove running from the periphery to near the center, coining the term gramophone for disc record players, predominantly used in many languages. Improvements through the years included modifications to the turntable and its drive system, the stylus or needle, the sound and equalization systems; the disc phonograph record was the dominant audio recording format throughout most of the 20th century. In the 1980s, phonograph use on a standard record player declined due to the rise of the cassette tape, compact disc, other digital recording formats. However, records are still a favorite format for some audiophiles, DJs and turntablists, have undergone a revival in the 2010s.
The original recordings of musicians, which may have been recorded on tape or digital methods, are sometimes re-issued on vinyl. Usage of terminology is not uniform across the English-speaking world. In more modern usage, the playback device is called a "turntable", "record player", or "record changer"; when used in conjunction with a mixer as part of a DJ setup, turntables are colloquially called "decks". In electric phonographs, the motions of the stylus are converted into an analogous electrical signal by a transducer converted back into sound by a loudspeaker; the term phonograph was derived from the Greek words φωνή and γραφή. The similar related terms gramophone and graphophone have similar root meanings; the roots were familiar from existing 19th-century words such as photograph and telephone. The new term may have been influenced by the existing words phonographic and phonography, which referred to a system of phonetic shorthand. Arguably, any device used to record sound or reproduce recorded sound could be called a type of "phonograph", but in common practice the word has come to mean historic technologies of sound recording, involving audio-frequency modulations of a physical trace or groove.
In the late-19th and early-20th centuries, "Phonograph", "Gramophone", "Graphophone", "Zonophone", the like were still brand names specific to various makers of sometimes different machines. "Talking machine" had earlier been used to refer to complicated devices which produced a crude imitation of speech, by simulating the workings of the vocal cords and lips – a potential source of confusion both and now. In British English, "gramophone" may refer to any sound-reproducing machine using disc records, which were introduced and popularized in the UK by the Gramophone Company. "gramophone" was a proprietary trademark of that company and any use of the name by competing makers of disc records was vigorously prosecuted in the courts, but in 1910 an English court decision decreed that it had become a generic term. The term "phonograph" was restricted to machines that used cylinder records. "Gramophone" referred to a wind-up machine. After the introduction of the softer vinyl records, 33 1⁄3-rpm LPs and 45-rpm "single" or two-song records, EPs, the common name became "record player" or "turntable".
The home record player was part of a system that included a radio and might play audiotape cassettes. From about 1960, such a system began to be described as a "hi-fi" or a "stereo". In American English, "phonograph", properly specific to machines made by Edison, was sometimes used in a generic sense as early as the 1890s to include cylinder