6SN7 is a dual
triodeA triode is an electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube with three elements: the filament or cathode, the grid, and the plate or anode...
vacuum tubeIn electronics, a vacuum tube, electron tube , thermionic valve, or valve is a device used to amplify, switch, otherwise modify, or create an electrical signal by controlling the movement of electrons in a low-pressure space...
, on an 8 pin octal base. Although the 6S—series tubes are often metal cased, the 6SN7 is generally found only in a glass GT size envelope. The 6SN7 is basically two 6J5 triodes in one glass envelope.
Originally released in 1939 it was officially registered in 1941 as the glass-cased 6SN7GT. During
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
a 6SN7A was developed as a slightly improved version, then also a more rugged 6SN7W for military use.
With the advent of television the 6SN7 was well suited for use as a vertical-deflection amplifier.
6SN7 is a dual
triodeA triode is an electronic amplification device having three active electrodes. The term most commonly applies to a vacuum tube with three elements: the filament or cathode, the grid, and the plate or anode...
vacuum tubeIn electronics, a vacuum tube, electron tube , thermionic valve, or valve is a device used to amplify, switch, otherwise modify, or create an electrical signal by controlling the movement of electrons in a low-pressure space...
, on an 8 pin octal base. Although the 6S—series tubes are often metal cased, the 6SN7 is generally found only in a glass GT size envelope. The 6SN7 is basically two 6J5 triodes in one glass envelope.
History
Originally released in 1939 it was officially registered in 1941 as the glass-cased 6SN7GT. During
World War IIWorld War II, or the Second World War , was a global military conflict which involved a majority of the world's nations, including all great powers, organized into two opposing military alliances: the Allies and the Axis...
a 6SN7A was developed as a slightly improved version, then also a more rugged 6SN7W for military use.
With the advent of television the 6SN7 was well suited for use as a vertical-deflection amplifier. As screen sizes became larger, the tube started to have marginal voltage and power headroom. To address this, upgraded versions GTA (
General ElectricThe General Electric Company, or GE , is a multinational American technology and services conglomerate incorporated in the State of New York. In 2009, Forbes ranked GE as the world's largest company...
, 1950) and GTB (GE, 1954) were made with higher peak voltage and power ratings. The 6SN7GTA has
anodeAn anode is an electrode through which electric current flows into a polarized electrical device. Mnemonic: ACID . Electrons flow in the opposite direction to the electric current...
dissipation uprated to 5.0 watts "design center rating". The 6SN7GTB is identical to the 6SN7GTA except for a controlled heater warmup time, for use in
TelevisionTelevision is a widely used telecommunication medium for transmitting and receiving moving images, either monochromatic or color, usually accompanied by sound. "Television" may also refer specifically to a television set, television programming or television transmission...
sets with 600 mA
seriesComponents of an electrical circuit or electronic circuit can be connected in many different ways. The two simplest of these are called series and parallel and occur very frequently. Components connected in series are connected along a single path, so the same current flows through all of the...
heater strings.
The 6SN7 has a 6.3 V 600 mA heater/filament. The 12 volt filament equivalent is the 12SN7GT or 12SN7GTA. (12.6 V 300 mA filament) There was also a comparatively rare 8SN7 (8.4V@450mA filament intended for 450 mA series string TV sets)
Numerous other variations on the 6SN7 type have been offered over the years, including 7N7 (Sylvania 1940, loktal-base version), 5692 (RCA 1948, a super-premium version with guaranteed 10,000 hour lifetime), 12SX7 (RCA 1946, intended for use in 26-volt aircraft electronics), 1633 (RCA 1941, also for 26-V radios), 6042 (1951, another 1633 type), and 6180 (1952). American military designator for the 6SN7GA was VT-231, and the British called it CV1986 or CV1988. European designators include ECC32, 13D2 and B65. Each of the giant
SAGEThe Semi-Automatic Ground Environment was an automated control system for tracking and intercepting enemy bomber aircraft used by NORAD from the late 1950s into the 1980s...
computer systems used hundreds of 5692s as
flip-flopIn digital circuits, a flip-flop is a term referring to an electronic circuit that has two stable states and thereby is capable of serving as one bit of memory...
s.
While often used as an audio amplifier in the 1940-1955 period, usually in the driver stages of power amps, the 6SN7 was also very popular in television vertical sweep applications. The designer of the famous
Williamson amplifierA Williamson amplifier refers to a type of vacuum tube amplifier whose circuit design is similar to that originally published by D.T.N. Williamson.- Explanation :...
, one of the first true high-fidelity designs, suggested use of the 6SN7 since it was similar to the British triodes that he used in his circuit. In most late-1950s applications it was replaced by the
12AU712AU7 is a miniature 9-pin medium-gain dual triode vacuum tube. It belongs to a large family of dual triode vacuum tubes which share the same pinout . 12AU7 is also known in Europe under its Mullard-Philips tube designation ECC82...
, then by
transistorA transistor is a semiconductor device commonly used to amplify or switch electronic signals. A transistor is made of a solid piece of a semiconductor material, with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's...
s in the 1960s.
6SN7s are still manufactured in Russia and China under the old Soviet designator 6N8S, and continue to be used in some modern tube high-fidelity equipment. The 6SN7 is similar,
but not identical, in electrical characteristics to the 12AU7.
The 6CG7 is a miniature tube (RCA, 1951) that has very similar ratings. It was also made as an 8.4V 450mA series string type as the 8CG7. The British made a single triode with identical characteristics as one half of a 6SN7, its number is L63.
See also
- List of vacuum tubes
- 6SL7
- 12AT7
12AT7 is a miniature 9-pin medium-gain dual triode vacuum tube popular in guitar amplifiers. It belongs to a large family of dual triode vacuum tubes with share the same pinout and of which 12AX7 is the most proliferous type....
- 12AU7
12AU7 is a miniature 9-pin medium-gain dual triode vacuum tube. It belongs to a large family of dual triode vacuum tubes which share the same pinout . 12AU7 is also known in Europe under its Mullard-Philips tube designation ECC82...
- 12AX7
12AX7 is a miniature dual triode vacuum tube with high voltage gain. It is believed to have been originally developed in 1946 by RCA engineers in Harrison, New Jersey under developmental number A-4522. It was released for public sale under the 12AX7 identifier on September 15, 1947...
- 12BH7
- 6CG7
- L63