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Valve Audio Amplifiers
A valve audio amplifier ( UK) or vacuum tube audio amplifier ( US) is a valve amplifier used for sound reinforcement, sound recording and reproduction. Until the invention of solid state devices such as the transistor, all electronic amplification was produced by valve (tube) amplifiers. While solid-state devices prevail in most audio amplifiers today, valve audio amplifiers are still used where their audible characteristics are considered pleasing, for example in music performance or music reproduction. Instrument and vocal amplification Valve amplifiers for guitars (and to a lesser degree vocals and other applications) have different purposes from those of hi-fi amplifiers. The purpose is not necessarily to reproduce sound as accurately as possible, but rather to fulfill the musician's concept of what the sound should be. For example, distortion is almost universally considered undesirable in hi-fi amplifiers but may be considered a desirable characteristic in performance. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many smaller islands within the British Isles. Northern Ireland shares a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between the Kingdom of England (which included Wales, annexed in 1542) and the Kingdom of Scotland in 170 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EL34
The EL34 is a thermionic vacuum tube of the power pentode type. The EL34 was introduced in 1955 by Mullard, who were owned by Philips. The EL34 has an octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits; it was also designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. The USSR analog was 6P27S (Cyrillic: 6П27C). Specifications In common with all 'E' prefix tubes, using the Mullard–Philips tube designation, the EL34 has a heater voltage of 6.3 V. According to the data sheets found in old vacuum tube reference manuals, a pair of EL34s with 800 V plate voltage can produce 90 watts output in class AB1 in push–pull configuration. However, this configuration is rarely found. One application of this type was in "Australian Sound" public address amplifiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Williamson Amplifier
The Williamson amplifier is a four-stage, push-pull, Class A triode-output valve audio power amplifier designed by D. T. N. Williamson during World War II. The original circuit, published in 1947 and addressed to the worldwide do it yourself community, set the standard of high fidelity sound reproduction and served as a benchmark or reference amplifier design throughout the 1950s. The original circuit was copied by hundreds of thousands amateurs worldwide. It was an absolute favourite on the DIY scene of the 1950s, and in the beginning of the decade also dominated British and North American markets for factory-assembled amplifiers. The Williamson circuit was based on the 1934 '' Wireless World Quality Amplifier'' by Walter Cocking, with an additional error amplifier stage and a global negative feedback loop. Deep feedback, triode-connected KT66 power tetrodes, conservative choice of standing currents, and the use of wide-bandwidth output transformer all contributed to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Feedback
Negative feedback (or balancing feedback) occurs when some function (Mathematics), function of the output of a system, process, or mechanism is feedback, fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances. Whereas positive feedback tends to lead to instability via exponential growth, oscillation or chaos theory, chaotic behavior, negative feedback generally promotes stability. Negative feedback tends to promote a settling to List of types of equilibrium, equilibrium, and reduces the effects of perturbations. Negative feedback loops in which just the right amount of correction is applied with optimum timing can be very stable, accurate, and responsive. Negative feedback is widely used in mechanical and electronic engineering, and also within living organisms, and can be seen in many other fields from chemistry and economics to physical systems such as the climate. General negative feedback ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audiophile
An audiophile is a person who is enthusiastic about high-fidelity sound reproduction. An audiophile seeks to reproduce the sound of a piece of recorded music or a live musical performance, typically inside closed headphones, In-ear monitors, open headphones in a quiet listening space, or a room with good acoustics. Audiophile values may be applied at all stages of music reproduction: the initial audio recording, the production process, and the playback, which is usually in a home setting. In general, the values of an audiophile are seen to be antithetical to the growing popularity of more convenient but lower quality music, especially lossy digital file types like MP3, lower definition streaming services, and inexpensive headphones. The term ''high-end audio'' refers to playback equipment used by audiophiles, which may be bought at specialist shops and websites. High-end components include turntables, digital-to-analog converters, equalization devices, preamplifiers and amplifie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Telephone Cable
A submarine communications cable is a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean and sea. The first submarine communications cables laid beginning in the 1850s carried telegraphy traffic, establishing the first instant telecommunications links between continents, such as the first transatlantic telegraph cable which became operational on 16 August 1858. Subsequent generations of cables carried telephone traffic, then data communications traffic. Modern cables use optical fibre technology to carry digital data, which includes telephone, Internet and private data traffic. Modern cables are typically about in diameter and weigh around for the deep-sea sections which comprise the majority of the run, although larger and heavier cables are used for shallow-water sections near shore. Submarine cables first connected all the world's continents (except Antarctica) when Java was connected to Darwin, Northern Terr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6SN7
6SN7 is a dual triode vacuum tube with an eight-pin octal base. It provides a medium gain (20 dB). The 6SN7 is basically two 6J5 triodes in one envelope. History Originally released in 1939 it was officially registered in 1941 by RCA and Sylvania as the glass-cased 6SN7GT, originally listed on page 235 of RCA's 1940 RC-14 Receiving Tube Manual, in the Recently Added section, as: 6SN7-GT. Although the 6S-series tubes are often metal-cased, there was never a ''metal-envelope'' 6SN7 (there being no pin available to connect the metal shield); there were, however, a few glass-envelope tubes with a metal band, such as the 6SN7A developed during World War II - slightly improved in some respects but the metal band was prone to splitting. Numerous variations on the 6SN7 type have been offered over the years, including: * 7N7 (Sylvania 1940, short-lived loktal-base version), * 1633 (RCA 1941, also for 26-V radios), * 12SX7 (RCA 1946, intended for use in 12-volt aircraft electronics), * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
12AX7
12AX7 (also known as ECC83) is a miniature dual-triode 6AV6 vacuum tube with high voltage gain. Developed around 1946 by RCA engineers in Camden, New Jersey, under developmental number A-4522, it was released for public sale under the 12AX7 identifier on September 15, 1947. The 12AX7 was originally intended as replacement for the 6SL7 family of dual-triode amplifier tubes for audio applications. As a popular choice for guitar tube amplifiers, its ongoing use in such equipment makes it one of the few small-signal vacuum tubes in continuous production since it was introduced. History The 12AX7 is a twin triode basically composed of two of the triodes from a 6AV6, a double diode triode. The 6AV6 is a miniature repackaging (with just a single cathode) of the triode and twin diodes from the octal 6SQ7 (a double-diode triode used in AM radios), which itself is very similar to the older type 75 triode-diode dating from 1930. Application The 12AX7 is a high-gain (typical amplifica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
12AU7
The 12AU7 and its variants are miniature nine-pin (B9A base) medium-gain dual triode vacuum tubes. It belongs to a large family of dual triode vacuum tubes which share the same pinout (RETMA tube designation, RETMA 9A). 12AU7 is also known in Europe under its Mullard–Philips tube designation ECC82. There are many equivalent tubes with different names, some identical, some designed for ruggedness, long life, or other characteristics; examples are the US military 5814A and the European special-quality ECC82 and E182CC. The tube is popular in hi-fi vacuum tube audio as a low-noise line amplifier, driver (especially for tone stacks), and phase-inverter in vacuum tube push–pull amplifier circuits. It was widely used, in special-quality versions such as ECC82 and 5814A, in pre-semiconductor digital computer circuitry. Use of special-quality versions outside of the purpose they were designed for may not be optimal; for example, a version for digital computers may be designed for lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
12AT7
12AT7 (also known in Europe by the Mullard–Philips tube designation of ECC81) is a miniature 9-pin medium-gain (60) dual-triode vacuum tube popular in guitar amplifiers. It belongs to a large family of dual triode vacuum tubes which share the same pinout (EIA 9A), including in particular the very commonly used low- mu 12AU7 and high-mu 12AX7. The 12AT7 has somewhat lower voltage gain than the 12AX7, but higher transconductance and plate current, which makes it suitable for high frequency applications. Originally the tube was intended for operation in VHF circuits, such as TV sets and FM tuners, as an oscillator/frequency converter, but it also found wide use in audio as a driver and phase-inverter in vacuum tube push–pull amplifier circuits. This tube is essentially two 6AB4/EC92s in a single envelope. Unlike the situation with the 6C4 and 12AU7, both the 6AB4 and the 12AT7 are described by manufacturer's data sheets as R.F. devices operating up to VHF frequencies.Tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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