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Ultra-linear
Ultra-linear electronic circuits are those used to couple a tetrode or pentode vacuum-tube (also called "electron-valve") to a load (e.g. to a loudspeaker). 'Ultra-linear' is a special case of 'distributed loading'; a circuit technique patented by Alan Blumlein in 1937 (Patent No. 496,883), although the name 'distributed loading' is probably due to Mullard. In 1938 he applied for the US patent 2218902. The particular advantages of ultra-linear operation, and the name itself, were published by David Hafler and Herbert Keroes in the early 1950s through articles in the magazine "Audio Engineering" from the USA.Alt URL The special case of 'ultra linear' operation is sometimes confused with the more general principle of distributed loading. Operation A |
David Hafler
David Hafler (February 7, 1919 – May 25, 2003) was an American audio engineer. He was best known for his work on an improved version of the Williamson amplifier using the ultra-linear circuit of Alan Blumlein. Biography In 1950, Hafler founded Acrosound with his colleague Herbert Keroes. This company was primarily in the business of designing and manufacturing transformers for tube amplifiers. Around this time Hafler and Keroes popularized the ultra-linear output-stage for audio amplifiers. However, the partnership did not last. In 1954 Hafler founded Dynaco with Ed Laurent. Hafler was instrumental in bringing affordable, high-quality audio kits to hobbyists, making his name a household word in the US audio community for many years. In the 1970s Hafler promoted "passive pseudo-quadraphonics", an inexpensive method of recreating ambient sounds at the rear from ordinary stereophonic recordings. Known as the "Hafler hookup" or " Hafler circuit", this consisted of two simila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrode
A tetrode is a vacuum tube (called ''valve'' in British English) having four active electrodes. The four electrodes in order from the centre are: a thermionic cathode, first and second grids, and a plate electrode, plate (called ''anode'' in British English). There are several varieties of tetrodes, the most common being the screen-grid tube and the beam tetrode. In screen-grid tubes and beam tetrodes, the first grid is the control grid and the second grid is the screen grid. In other tetrodes one of the grids is a control grid, while the other may have a variety of functions. The tetrode was developed in the 1920s by adding an additional grid to the first amplifying vacuum tube, the triode, to correct limitations of the triode. During the period 1913 to 1927, three distinct types of tetrode valves appeared. All had a normal control grid whose function was to act as a primary control for current passing through the tube, but they differed according to the intended function of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentode
A pentode is an electronic device having five electrodes. The term most commonly applies to a three-grid amplifying vacuum tube or thermionic valve that was invented by Gilles Holst and Bernhard D.H. Tellegen in 1926. The pentode (called a ''triple-grid amplifier'' in some literature) was developed from the ''screen-grid tube'' or ''shield-grid tube'' (a type of tetrode tube) by the addition of a grid between the screen grid and the plate. The screen-grid tube was limited in performance as an amplifier due to secondary emission of electrons from the plate. The additional grid is called the ''suppressor grid''. The suppressor grid is usually operated at or near the potential of the cathode and prevents secondary emission electrons from the plate from reaching the screen grid. The addition of the suppressor grid permits much greater output signal amplitude to be obtained from the plate of the pentode in amplifier operation than from the plate of the screen-grid tube at the same plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loudspeaker
A loudspeaker (commonly referred to as a speaker or, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. The driver is a linear motor connected to a diaphragm, which transmits the motor's movement to produce sound by moving air. An audio signal, typically originating from a microphone, recording, or radio broadcast, is electronically amplified to a power level sufficient to drive the motor, reproducing the sound corresponding to the original unamplified signal. This process functions as the inverse of a microphone. In fact, the ''dynamic speaker'' driver—the most common type—shares the same basic configuration as a dynamic microphone, which operates in reverse as a generator. The dynamic speaker was invented in 1925 by Edward W. Kellogg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alan Blumlein
Alan Dower Blumlein (; 29 June 1903 – 7 June 1942) was an English electronics engineer, notable for his many inventions in telecommunications, sound recording, stereophonic sound, television and radar. He received 128 patents and was considered 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 then under development, when all on board the Halifax bomber in which he was flying were killed when it crashed at Welsh Bicknor in Herefordshire. Early life Alan Dower Blumlein was born on 29 June 1903 in Hampstead, London. His father, Semmy Blumlein, was a German-born naturalised British subject. Semmy was the son of Joseph Blumlein, a German of Jewish descent, and Philippine Hellmann, a French woman of German descent.Semmy Blumlein's father, Joseph B. Blumlein was Jewish, ''see Burns, p. 2'' Alan's mother, Jessie Dower, was Scottish, daughter of William Dow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullard
Mullard Limited was a British manufacturer of electronics, electronic components. The Mullard Radio Valve Co. Ltd. of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed thermionic valves (US term: vacuum tube) for the Admiralty before becoming managing director of the Z Electric Lamp Co. The company soon moved to Hammersmith, London and then in 1923 to Balham, London. The head office in later years was Mullard House at 1–19 Torrington Place, Bloomsbury, now part of University College London. Start-up In 1921, the directors were Sir Ralph Ashton (chairman), Basil Binyon of the Radio Communication Co, Cyril Frank Elwell, C.F. Elwell and S.R. Mullard (managing director). Partnership with Philips In 1923, to meet the technical demands of the newly formed BBC, Mullard formed a partnership with the Dutch manufacturer Philips. The vacuum tube, valves (vacuum tubes) produced in this period were named with the prefix PM, for Philip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullard Circuits For Audio Amplifiers
Mullard Circuits for Audio Amplifiers is a famous book by the Technical Services Department of Mullard Ltd, a British valve manufacturing company. First published in 1959 and then reprinted several times it contained a number of designs by Mullard engineers for high quality audio amplifiers, which were to be used by amateur constructors as well as by manufacturers as the basis for many products that formed part of the high fidelity audio movement in Britain in the 1960s. Particularly iconic designs were the Mullard 5-10 and the Mullard 5-20, ten and twenty watt power amplifier An audio power amplifier (or power amp) amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power a ...s. Circuits for preamplifiers with tone controls and tape recorder amplifiers were also included, along with information regarding record and tape equalisation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mullard 5-10
The Mullard 5-10 was a Electronic circuit, circuit for a valve amplifier designed by the British vacuum tube, valve company, Mullard in 1954 at the Mullard Applications Research Laboratory (ARL) in Mitcham Surrey UK, part of the New Road factory complex, to take advantage of their particular products. The circuit was first published in Practical Wireless magazine. The amplifier featured five valves and an output of 10 watts - hence '5-10'. Of those valves, one was a full-wave rectifier (an EZ80 or EZ81), one was a pre-amplifier pentode EF86 and one a double-triode 12AX7, ECC83 as phase splitter. The power amplification was handled by a pair of EL84 working in Electronic amplifier, push-pull configuration. The frequency response of the circuit was from 40Hz to 20,000Hz with less than 0.2% Total harmonic distortion, THD. In 1959 Mullard published its famous booklet "Mullard Circuits for Audio Amplifiers" covering a range of amplifier and pre-amplifier circuits using valves develope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LEAK
A leak is a way (usually an opening) for fluid to escape a container or fluid-containing system, such as a Water tank, tank or a Ship, ship's Hull (watercraft), hull, through which the contents of the container can escape or outside matter can enter the container. Leaks are usually unintended and therefore undesired. The word ''leak'' usually refers to a gradual loss; a sudden loss is usually called a ''spill''. The matter leaking in or out can be gas, liquid, a highly Viscosity, viscous paste (substance), paste, or even a solid such as a Powder (substance), powdered or granular solid or other solid particles. Types and possible causes Types of leak openings include a puncture, gash, rust or other corrosion hole, very tiny ''pinhole leak'' (possibly in imperfect Welding, welds), crack or microcrack, or inadequate sealing between components or parts joined. When there is a puncture, the size and shape of the leak can often be seen, but in many other cases, the size and shape of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quad Electroacoustics
QUAD Electroacoustics is a British manufacturer of hi-fi equipment, based Huntingdon, England. QUAD is part of the IAG Group, with corporate headquarters located in Shenzhen, China. Corporate history The company was founded by Peter J. Walker in 1936 in London, and was initially called ''S.P. Fidelity Sound Systems''. In 1936 the name was changed to the ''Acoustical Manufacturing Co. Ltd''. The company moved from London to Huntingdon in 1941 after being bombed out of London in World War II. The company initially produced only public address equipment but after the war they began to produce equipment designed for use in the home as a result of the rising demand for high quality domestic sound reproduction. Within a few years the company had transitioned almost entirely to manufacturing models for the home audio market. Walker was quoted in December 1975 in Wireless World magazine, "An audio power amplifier is required to produce an output signal that differs from the input si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
McIntosh Laboratories
McIntosh Laboratory is an American manufacturer of handcrafted high-end audio equipment that is headquartered in Binghamton, New York. It is a subsidiary of McIntosh Group, which in November 2024 was acquired by Bose Corporation, a fellow American audio company. The company was co-founded in 1949 by Frank H. McIntosh and Gordon Gow. McIntosh designs and produces audio amplifiers, stereo tuners, loudspeakers, turntables, music streamers, processors, and various other audio products. Although solid state components are a large segment of the McIntosh line, audio enthusiasts most revere the warm sound of the company's tube amplifiers. Some of their tube amplifiers rank among the finest ever created for home audio and theater use. Their Unity Coupled Circuit, patented at the brand's inception, is still used today in products like their MC275 amplifier, whose vacuum tubes—used in many of the company's products—help to impart a lifelike warmth and soul to the sound. ''"McIntosh tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Research Corp
Audio Research Corporation ("ARC") is one of the oldest manufacturers of high-end audio equipment still in operation. The company was known to be a pioneer at advancing state-of-the-art audio reproduction in the 1970s, and for re-introducing the vacuum tube as the primary active amplification device. With the help of reviews in audiophile publications such as ''Stereophile'' and ''The Absolute Sound'', it solidified its position as a well-respected audio manufacturer. Many industry observers consider the founder, William Zane Johnson, as one of the true originators of the entire concept of high-end audio High-end audio is a class of consumer home audio equipment marketed to audiophiles on the basis of high price or quality, and esoteric or novel sound reproduction technologies. The term can refer simply to the price, to the build quality of th ... as it exists today. As audio critic Jonathan Valin put it: “Where would the high end be without William Zane Johnson . . . ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
