6L6 is the designator for a
beam power tube introduced by
Radio Corporation of America
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
in April 1936 and marketed for application as a power amplifier for audio frequencies.
[J. F. Dreyer Jr.]
"The Beam Power Output Tube"
New York: McGraw-Hill, ''Electronics'', April 1936, pp. 18 - 21, 35 The 6L6 is a
beam tetrode
A beam tetrode, sometimes called a beam power tube, is a type of vacuum tube or thermionic valve that has two grids and forms the electron stream from the cathode into multiple partially collimated beams to produce a low potential space cha ...
that utilizes formation of a low potential
space charge
Space charge is an interpretation of a collection of electric charges in which excess electric charge is treated as a continuum of charge distributed over a region of space (either a volume or an area) rather than distinct point-like charges. This ...
region between the anode and screen grid to return anode
secondary emission
In particle physics, secondary emission is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The term often refers to the emi ...
electrons to the anode and offers significant performance improvements over power pentodes.
[ The 6L6 was the first successful beam power tube marketed. In the 21st century, variants of the 6L6 are manufactured and used in some high fidelity audio amplifiers and musical instrument amplifiers.
]
History
In the UK, three engineers at EMI
EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British transnational conglomerate founded in March 1931 in London. At the time of its break-up in 201 ...
(Isaac Shoenberg
Sir Isaac Shoenberg (1 March 1880 – 25 January 1963) was a British electronic engineer born in Belarus who was best known for his role in the history of television. He was the head of the EMI research team that developed the 405-line (Marconi-EM ...
, Cabot Bull
Cabot may refer to:
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* Cabot Creamery, an American dairy cooperative
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* Alexandra Cabot, in the ''Law & Order'' universe
* Leigh Cabot, from Stephen King's 1983 n ...
and Sidney Rodda
Sidney may refer to:
People
* Sidney (surname), English surname
* Sidney (given name), including a list of people with the given name
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* Si ...
) had developed and filed patents in 1933 and 1934 on an output tetrode that utilized novel electrode structures to form electron beams to create a dense space charge region between the anode and screen grid to return anode secondary electrons to the anode. The new tube offered improved performance compared to a similar power pentode and was introduced at the Physical and Optical Societies' Exhibition in January 1935 as the Marconi N40.[Editors]
"New Output Tetrode"
New York: McGraw-Hill, ''Electronics'', Feb. 1935, p. 65 Around one thousand of the N40 output tetrodes were produced, but MOV (Marconi-Osram Valve
M-OV (Marconi-Osram Valve Company) was a British manufacturer of thermionic valves (vacuum tubes). It was a subsidiary of the (British) General Electric Company Ltd.
The company was founded in 1919, when the valve making interests of GEC (Osra ...
) company, under the joint ownership of EMI
EMI Group Limited (originally an initialism for Electric and Musical Industries, also referred to as EMI Records Ltd. or simply EMI) was a British transnational conglomerate founded in March 1931 in London. At the time of its break-up in 201 ...
and GEC, considered the design too difficult to manufacture due to the need for good alignment of the grid wires.[K. R. Thrower, ''British Radio Valves The Classic Years: 1926-1946'', Reading, UK: Speedwell, 2009, pp. 125 - 126] As MOV had a design-share agreement with RCA
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
of America, the design was passed to that company.
The metal tube technology utilized for the 6L6 had been developed by General Electric and introduced in April 1935, with RCA manufacturing the metal envelope tubes for GE at that time. Some of the advantages of metal tube construction over glass envelope tubes were smaller size, ruggedness, electromagnetic shielding and smaller interelectrode capacitance. The 6L6 incorporated an octal
The octal numeral system, or oct for short, is the radix, base-8 number system, and uses the Numerical digit, digits 0 to 7. This is to say that 10octal represents eight and 100octal represents sixty-four. However, English, like most languages, ...
base, which had been introduced with the GE metal tubes. The 6L6 was rated for 3.5 watts screen power dissipation and 24 watts combined plate and screen dissipation. The 6L6 and variants of it became popular for use in public address amplifiers, musical instrument amplifiers, radio frequency applications and audio stages of radio transmitters. The 6L6 family has had one of the longest active lifetimes of any electronic component, more than 80 years. As of 2021, variants of the 6L6 are manufactured in Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, and Slovakia
Slovakia (; sk, Slovensko ), officially the Slovak Republic ( sk, Slovenská republika, links=no ), is a landlocked country in Central Europe. It is bordered by Poland to the north, Ukraine to the east, Hungary to the south, Austria to the s ...
.
Variations
The voltage and power ratings of the 6L6 series were gradually pushed upwards by such features as thicker plates, grids of larger diameter wire, grid cooling fins, ultra-black plate coatings and low loss materials for the base. Variants of the 6L6 included the 6L6G, 6L6GX, 6L6GA, 6L6GAY, 6L6GB, 5932/6L6WGA and the 6L6GC. All variants after the original 6L6 utilized glass envelopes. A "W" in the descriptor identified the tube as designed to withstand greater vibration and impact. A "Y" in the descriptor indicated that the insulating material of the base wa
Micanol
Application
The high transconductance and high plate resistance of the 6L6 requires circuit design that incorporates topologies and components that smooth out the frequency response, suppress voltage transients and prevent spurious oscillation.[L. C. Holland]
"Circuit Design Related to Tube Performance"
New York: McGraw-Hill, ''Electronics'', Mar. 1939, pp. 18 - 20
Characteristics
Improved substitute
* 5881
Similar tubes
* 6P3S (6П3С)
* 6P3S-E (6П3С-E)
* 7027a
7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube.
As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion, mythology, s ...
See also
* 6V6
The 6V6 is a beam-power tetrode vacuum tube. The first of this family of tubes to be introduced was the 6V6G by Ken-Rad Tube & Lamp Corporation in late 1936, with the availability by December of both Ken-Rad and Raytheon 6V6G tubes announced. ...
* KT66
KT66 is the designator for a beam power tube introduced by Marconi-Osram Valve Co. Ltd. (M-OV) of Britain in 1937 and marketed for application as a power amplifier for audio frequencies and driver for radio frequencies.Editors "The New Valves" ''W ...
* KT88 The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification.
Features
The KT88 fits a standard eight-pin octal socket and has similar pinout and applications as the 6L6 and EL34. Specifically designed for audio ...
* 6550
Tung-Sol was an American manufacturer of electronics, mainly lamps and vacuum tubes.
History
Tung-Sol was founded as Tung-Sol Lamp Works Inc. in Newark, New Jersey in 1907. Their early products were mainly geared towards the automotive mark ...
* 6CA7
* 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 st ...
* List of vacuum tubes
This is a list of vacuum tubes or ''thermionic valves'', and low-pressure gas-filled tubes, or ''discharge tubes''. Before the advent of semiconductor devices, thousands of tube types were used in consumer electronics. Many industrial, military or ...
References
External links
TDSL_Tube_data_[6L6
/nowiki>.html" ;"title="L6">TDSL Tube data [6L6
/nowiki>">L6">TDSL Tube data [6L6
/nowiki>
Electron Tube Data sheets
Several 6L6 datasheets from various manufacturers
* {{cite web , url=http://www.amplifiedparts.com/sites/all/modules/custom/tech_corner/files/6l6gc_comparison_of_current_made_tubes.pdf , title=6L6GC Comparison of Current Made Tubes , type=PDF , author=Kurt Prange , access-date=2014-02-16 , archive-url=https://web.archive.org/web/20140221181448/http://www.amplifiedparts.com/sites/all/modules/custom/tech_corner/files/6l6gc_comparison_of_current_made_tubes.pdf , archive-date=2014-02-21 , url-status=dead
Reviews of 6L6 tubes
Vacuum tubes
Guitar amplification tubes
Telecommunications-related introductions in 1936