List of vacuum tubes

This is a list of vacuum tubes or thermionic valves. Before the advent of semiconductor devices, hundreds of tube types were used in consumer and industrial electronics; today only a few types are still used in specialized applications.

Numbering Systems

North American RETMA System (Receiving Tubes)

Main article: RETMA tube designation

The first character group is always a number, consisting of one to three numerals, and almost always represents the heater voltage to the nearest whole number. These numerals are followed by one or two letters assigned to the devices in some sort of semi-chronological order of development and introduction to the marketplace, and then another single numeral which represents the number of active elements in the tube (including any internal screen plus the heater in indirectly heated tubes - electrodes connected together internally count as one). Sometimes a string of up to three Roman letters can be suffixed to the overall number; these generally delineate various revisions and improvements to the original model or different bulb shapes.
Examples
6DJ8
6V6G, Type 6V6 with Shouldered Tubular, (ST), shaped bulb.
6V6GT, Type 6V6 with Tubular, (T), shaped bulb.
6L6GA, Type 6L6 with Shouldered Tubular, (ST), shaped bulb, revision A.
6L6GTB, Type 6L6 with Tubular, (T), shaped bulb, revision B, (higher power rating than revision A.
12AX7

"RETMA" is the acronym for the Radio Electronic Television Manufacturers Association, originally the RMA, later RTMA, then EIA (Electronic Industries Association).

For a detailed description of the RMA numbering system used for transmitting and special-purpose tubes, see RMA tube designation

West European System

This system is very descriptive of what type of device, (triode, diode, pentode etc.), it is applied to, but it is not as easy to remember specific types. Like the North American system the first symbol describes the heater voltage, in this case a Roman letter rather than a number. Further Roman letters, up to three, describe the device followed by one to three numerals assigned in a semi chronological order of type development.
Examples
ECC88 = 6DJ8
EB91 = 6AL5
EABC80 = 6AK8 or 6T8
DY86 = 1S2
UCH42
This system is described in more detail below, or one can go to a dedicated description under Mullard-Philips tube designation.

British Military CV Naming System

This system prefixes a three or four digit number with the letters "CV", meaning "common valve".^{[1] [2]} It was introduced during the Second World War to rationalise away the previous nomenclatures maintained separately by the War Office/Ministry of Supply, Admiralty and Air Ministry/Ministry of Aircraft Production on behalf of the three armed services (e.g. "ACR~", "AR~", "AT~", etc. for CRTs, receiving and transmitting valves used in army equipments, "NC~", "NR~" and "NT~" similarly for navy equipments and "VCR~", "VR~" and "VT~" etc. for air force equipments), in which three separate designations could in principle apply to the same valve (which often had at least one prototype commercial designation as well). These numbers generally have identical equivalents in both the North American, RETMA, and West European, Mullard-Philips, systems but they bear no resemblance to the assigned "CV" number.
Examples
CV1986 = 6SN7 = ECC33
CV4010 = SQ version of 6AK5 = E95F
CV4007 = SQ version of 6AL5 = E91AA

Note the 4000 numbers identify special-quality valves.

The principle behind the CV numbering scheme was also adopted by the US Joint Army-Navy JAN numbering scheme which was later considerably expanded into the US Federal and then NATO stock number system used by all NATO countries. This part-identification system ensures that every particular spare part (not merely thermionic valves) receives a unique stock number across the whole of NATO irrespective of the source, and hence is not held inefficiently as separate stores. In the case of CV valves, the stock number is always of the format 5960-99-000-XXXX where XXXX is the CV number (with a leading 0 if the CV number only has 3 digits).

U.S. Military Systems

One system prefixes a three-digit number with the letters "VT", presumably meaning "Vacuum Tube". Other systems prefix the number with the letters "JHS" or "JAN". The numbers following these prefixes can be "special" four-digit numbers, or domestic two- or three- digit numbers or simply the domestic North American "RETMA" numbering system. Like the British military system, these have many direct equivalents in the civilian types. Confusingly, the British also had two entirely different "VT" nomenclatures, one used by the Royal Air Force (see the preceding section) and the other used by the GPO (i.e. the state PTT service, where it may have stood for "valve, telephone"); none of these schemes corresponded in any way with each other.
Examples, "VT" numbering systems
North American VT90 = 6H6
British (RAF) VT90 = V.H.F. transmitting triode
British (GPO) VT90 = ML4 = CV1732 output triode

North American Radio Manufacturers Association, (RMA) System

This system uses a numeral and letter pair followed by two numerals. It is described in more detail under RMA tube designation.
Examples
2E26, popular amateur radio beam power tetrode
2D21 = EN91 = PL21, Tetrode Thyratron

North American Numeral-Only Systems

These are some of the oldest numbering systems, extending back to the early 1920s.

A two-digit numbering system, starting with the UV-201A, which was considered as "type 01", extended almost continuously up into the 80s.
Examples
30, a common amateur RF triode
57, a pentode used in cabinet and mantel wirelesses (radio receivers)
80, a dual-diode rectifier used in early power supplies or battery eliminators.

A three-digit system was developed and used by R.C.A., but also adopted by many other manufacturers, and typically encompassed rectifiers and radio transmitter output devices. Devices in the low 800s tend to be transmitter output types, those in the higher 800s are rectifiers and thyratrons, and those in the 900s tend to be special-purpose and high-frequency devices.
Examples
807, a common amateur radio and audio output beam-tetrode
866, a well-known mercury vapor rectifier
885, a triode thyratron.
955, a V.H.F. triode.

Marconi-Osram British System

The Marconi-Osram designation uses a single letter followed by two numerals and sometimes by a second letter identifying different versions of a particular type. This British system is quite old, extending back to the 1920s.
The letters generally denote the type, (diode, triode, pentode, etc.), or use, (frequency-changer, I.F. amplifier, detector, etc.), of the device and the numbers are issued sequentially for each new device developed.
Examples
L63 = Triode similar to one half of a 6SN7
U14 = 5AS4
Y61 = 6U5G
X61 = 6J8G
Z77 = 6AM6 = EF91

Other Numeral Only Systems

At least three different four digit numeral only systems exist, possibly one each from each side of the Atlantic and a third suffixed by "60". These tend to be used for devices used in industrial or commercial equipment.
Examples
6060 = 12AT7 = ECC81
6064 = 6AM6 = EF91
6080 = 6AS7

Other Letter-Numeral Systems

There are quite a number of these systems from different geographical realms, such as those used on devices from contemporary Russian and Chinese production. Other compound numbering systems were used to mark higher reliability types used in industrial or commercial equipment such as medical equipment like E.C.G./E.K.G. and X-Ray machines, industrial control equipment used in factories and power plants like chart recorders and servo equipment and aircraft avionics. Early computers and telecommunication equipment also called for valves and tubes with greater quality and reliability than those used in domestic and consumer equipment.
Examples
M8162 = B309 = 12AT7 = ECC81
M8083 = Z77 = 6AM6 = EF91
Some numbers are derived from the behavior of devices considered to be exceptional. The "kinkless Tetrodes", (pentodes in which the suppressor grid has been replaced by beam forming plates), with their "KT" prefix fall into this category. The 6L6, sometimes called a beam tetrode, is among the best-known examples of this electrode design.

Heater or filament voltages

Vacuum tubes fall into three main non-interchangeable categories according to their heater or filament voltage:

1. Battery types, with a low-power filament operated usually from 1 to 2V, all filaments connected in parallel.
2. Types for ac-only equipment with a transformer; all tube heaters rated at the same voltage and fed in parallel from a transformer winding, often at 6.3 V.
3. Types for equipment designed to run on either AC or dc mains power (ac/dc) without a transformer; all heaters connected in series, and tubes, plus additional ballast tube or power resistor, chosen so that the sum of the heater voltages equals the mains voltage. All tubes must be rated at the same heater current, typically 100, 150, 300 or 450 mA. Some tubes' heaters run at a voltage and current suitable for either series or parallel operation, e.g., 6.3 V at 300 mA.

Heater voltages of 7,8, 9, 10, 11, 16, 17, 20 and many other voltages existed, often with the same characteristics as a 6 or 12 volt heater part, sometimes intended for use in television set receivers ^[3] where the heaters were connected in series across the power line.^[4]

American designation (with European equivalents)

See also RETMA tube designation, RMA tube designation

"0 volt" gas-filled cold cathode tubes

• Voltage regulators. Function is similar to that of a zener diode. Note that letter order (A-B-C) indicates increasing voltage ratings on octal-based regulators and decreasing voltage ratings on miniature-based regulators.
  • 0A2 150 volt regulator, 7-pin miniature base
  • 0A3 75 volt regulator, octal base, aka VR-75
  • 0B2 105 volt regulator, 7-pin miniature base
  • 0B3 90 volt regulator, octal base, aka VR-90
  • 0C2 75 volt regulator, 7-pin miniature base
  • 0C3 105 volt regulator, octal base, aka VR-105
  • 0D3 150 volt regulator, octal base, aka VR-150
• Other cold-cathode tubes
  • 0A4G Gas triode
  • 0Y4 Half-wave gas rectifier
  • 0Z4 Full-wave gas rectifier, octal base. Widely used in vibrator power supplies in early automobile radio receivers.

1 volt heater/filament tubes

• Tubes with 1.0 to 1.4 volt heaters
  • 1A3 High frequency diode with indirectly heated cathode. Used as a detector in some portable AM/FM receivers.
  • 1R5 Pentagrid frequency converter, anode voltage in the 45-90 volt range.
  • 1S4 Power output pentode Class-A amplifier, anode voltage in the 45-90 volt range.
  • 1S5 Sharp cut-off pentode Class-A amplifier, and diode, used as detector and first A.F. stage in battery radio receivers. Anode voltage in the 67-90 volt range. (B7G base)
  • 1T4 Remote Cut-Off R.F. Pentode Class-A amplifier, used as R.F. and I.F. amplifier in battery radio receivers, similar characteristics to 6BA6.(B7G base)
  • 1U4 Sharp Cut-Off R.F. Pentode Class-A amplifier, used as R.F. and I.F. amplifier in battery radio receivers, similar characteristics to 6BA6.(B7G base)
  • 1B3GT High-voltage rectifier diode common in monochrome television receivers of the 1950s and early 1960s. Peak inverse voltage of 30Kv. Anode current 2mA Average, 17mA peak. Derived from the earlier industrial type 8016. (International Octal base.)

• Tubes with 1.4 volt DC heaters
  • 1A7GT Pentagrid converter
• 1G6-G Dual power triode. "GT" version also available.
  • 1L6 Pentagrid converter

1.25 Volt filament subminiature tubes

The following tubes were used in post-WW2 walkie-talkies and pocket-sized portable radios. All have 1.25 volt DC filaments and directly heated cathodes. Some specify which end of the filament is to be powered by the positive side of the filament power supply (usually a battery). All have glass bodies that measure from 0.285 to 0.400 inches (7.24 mm to 10.16 mm) wide, and from 1.25 to 2.00 inches (31.75 mm to 50.4 mm) in overall length.

Those labeled 8 pin have round bodies and bases with 8 stiff pins arranged in a circle. Those marked FL have elliptical bodies and flat bases with long, inline “flying leads” that are soldered into the circuit. Those marked SL are similar to those marked FL, but have short inline leads that can be soldered or can be mated with a special socket. (Flying leads can be cut short to fit into inline sockets.)

• 1AC5 Power pentode, FL
• 1AD4 Sharp-cutoff pentode, FL
• 1AD5 Sharp-cutoff pentode, 8 pin
• 1AE5 Heptode mixer, FL
• 1AG4 Power pentode, FL
• 1AG5 Diode, pentode, FL
• 1AH4 RF pentode, FL
• 1AJ5 Diode, sharp-cutoff pentode, FL
• 1AK4 Sharp-cutoff pentode, FL
• 1AK5 Diode, sharp-cutoff pentode, FL
• 1C8 Pentagrid converter, 8 pin
• 1D3 Low-mu high-frequency triode, 8 pin
• 1E8 Pentagrid converter, 8 pin
• 1Q6 Diode, pentode, 8 pin
• 1S6 Diode, pentode, 8 pin
• 1T6 Diode, pentode, 8 pin
• 1V5 Power pentode, 8 pin
• 1V6 Triode-pentode converter, FL
• 1W5 Sharp-cutoff pentode, 8 pin
• 2E31 Sharp-cutoff pentode, FL
• 2E32 Similar to 2E31, SL
• 2E35 Power pentode, FL
• 2E36 Similar to 2E35, SL
• 2E41 Diode, pentode, FL
• 2E42 Similar to 2E42, SL
• 2G41 Triode-heptode converter, FL
• 2G42 Similar to type 2G42, SL

1 prefix for home receivers

These tubes were made for home storage battery receivers manufactured during the early-to-mid 1930s. The numbers of the following tubes all start with 1, but these tubes all have 2.0 volt DC filaments. This numbering scheme was intended to differentiate these tubes from the tubes with 2.5 volt AC heaters listed below.

• 1A4-p Remote-cutoff pentode
• 1A4-t Remote-cutoff tetrode
• 1A6 Pentagrid converter, also occasionally used as a grid-leak detector. Not designed to receive shortwave frequencies above 10 megahertz.
• 1B4-p Sharp-cutoff pentode
• 1B4-t Sharp-cutoff tetrode
• 1B5 Dual detector diode, medium-mu triode. Usually numbered 1B5/25S.
• 1C5 Power pentode (similar to 3Q5 except for filament)
• 1C6 Pentagrid converter
• 1C7-G Octal version of type 1C6.
• 1D5-Gp Octal version of type 1A4-p.
• 1D5-Gt Octal version of type 1A4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
• 1D7-G Octal version of type 1A6.
• 1E5-Gp Octal version of type 1B4-p.
• 1E5-Gt Octal version of type 1B4-t. (Note: This is a shouldered "G" octal, not a cylindrical "GT" octal.)
• 1E7-G Twin power pentode for used as a driver when parallel-connected, or as a push-pull output. "GT" version also available
• 1F4 Power pentode
• 1F5-G Octal version of 1F4.
• 1F6 Duplex diode, sharp-cutoff pentode
• 1F7-G Octal version of type 1F6
• 1G5-G Power pentode
• 1H4-G Medium-mu triode, can be used as a power triode. Octal version of type 30, which is an upgraded version of type 01-A. "GT" version also available.
• 1H6-G Octal version of type 1B5/25S. "GT" version also available.
• 1J5-G Power pentode
• 1J6-G Dual power triode, octal version of type 19. "GT" version also available.

2 volt heater/filament tubes

• Tubes used in AC-powered radio receivers of the early 1930s. All have 2.5 volt heaters.
  • 2A3 Power Triode (Directly heated cathode, two triode units in parallel inside the same bulb), Used for A.F. output stages in 30s-40s audio amplifiers and radios.
  • 2A5 Power Pentode (Except for heater, electronically identical to types 42 and 6F6)
  • 2A6 Twin-diode, high-mu triode (Except for heater, electronically identical to type 75)
  • 2A7 Dual-tetrode-style pentagrid converter (Except for heater, electronically identical to types 6A7, 6A8 and 12A8)
  • 2B7 Twin-diode remote-cutoff pentode (Except for heater, electronically identical to type 6B7)
  • 2E5 and 2G5 Electron-ray indicators ("Eye tube") with integrated control triode. (Except for heater, electronically identical to types 6E5 and 6G5)

• Tubes used in television receivers
  • 2AF4 UHF triode oscillator
  • 2BN4 VHF RF triode
  • 2CW4 VHF RF triode (Nuvistor type)
  • 2CY5 VHF sharp-cutoff RF tetrode
  • 2EA5 VHF sharp-cutoff RF tetrode
  • 2EN5 Dual-diode
  • 2ER5 VHF RF triode
  • 2ES5 VHF RF triode
  • 2EV5 VHF sharp-cutoff RF tetrode
  • 2FH5 VHF RF triode
  • 2FQ5 VHF RF triode
  • 2FV6 VHF sharp-cutoff RF tetrode
  • 2FY5 VHF RF triode
• 2X2 High Vacuum High Peak inverse voltage diode, used as rectifier in C.R.T. supplies. Similar to 1B3 and 1S2 except for heater voltage.

5 volt heater/filament tubes

• 300B - 40 Watt directly heated triode
• 5AR4, GZ34 - Full wave rectifier
• 5AS4 - Full wave rectifier
• 5R4 - Full wave rectifier
• 5U4 - Full wave rectifier
• 5V4, GZ32 - Full wave rectifier
• 5Y3 - Full-wave rectifier, octal base version of type 80

6 volt heater/filament tubes

• 6AB4/EC92, High-mu triode (Pinout same as 6C4 except for pin 5 not having a connection)
• 6A6, Twin Power Triode, used as a Class A audio driver or a Class B audio output. UX6 base. 6.3 volt heater version of type 53 which had a 2.5 volt heater. Octal version -- 6N7.
• 6A7 and 6A8 (PH4, X63) : Superheterodyne Pentagrid converter -- dual tetrode style. Based on type 2A7, which had a 2.5 volt heater. 6A7 has a UX7 base with top cap connection for control grid (grid 4). 6A8 is octal version with top cap connection for control grid. Loctal version: type 7B8.
• 6AC7, 1852 Television Sharp Cutoff R.F. Pentode. (Often encountered in a black metal envelope, not to be confused with the 6CA7.)
• 6AD6-G and 6AF6-G "Magic Eye" tuning indicators. Both have two "pie wedge" shadow indicators, one each on opposite sides of a single circular indicator target. Both shadows may be used in tandem or may be driven by two different signal sources. Type 6AE6-G is specifically made to drive each indicator with different signals. May also be driven by separate pentodes with different characteristics. E.g., a sharp-cutoff pentode like a 6J7 -- which would be hyper-sensitive to any signal change—would drive one shadow, while a remote-cutoff pentode like a 6K7 -- which would only react to stronger signals—would drive the other shadow. Both tubes have octal bases. Type 6AD6-G, with a target voltage rated from 100 to 150 volts, is designed for AC/DC radios. Type 6AF6-G, with a target voltage rated at 250 volts, is designed for larger AC radios.
• 6AE6-G A driver triode specially designed for "Magic Eye" tuning indicator types 6AD6-G and 6AF6-G. Has a common heater and indirectly heated cathode, two internally connected triode grids—one with sharp cutoff characteristics, one with remote cutoff characteristics—and two plates, one for each grid. The sharp cutoff grid reacts to any signal change, while the remote cutoff grid reacts only to stronger signal changes.
• 6AF4 UHF Medium mu Triode, commonly found in television UHF tuners and converters.
• 6AH5-G Beam power tube for early television use. Same as type 6L6-G, but with scrambled pinout. Used in some Philco sets.
• 6AK5, EF91, 5654, CV4010, 62H1P Miniature V.H.F. Sharp cut-off Pentode (Used in old "Radiosonde" weather balloon transmitters, receiver front ends and contemporary audio equipment) B7G, (Miniature 7 pin) base
• 6AK6 Power pentode. 7-pin miniature version of type 6G6-G. Unusual low-power consumption output tube with 150 ma heater.
• 6AK8, EABC80. Triple Diode, High-mu Triode. Diodes have identical characteristics—two have cathodes connected to the triode's cathode, one has an autonomous cathode. Used as a combination AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in AM/FM radios manufactured outside of North America. Triode amplification factor: 70. North American type 6T8 is identical (but for a shorter glass envelope) and may be used as a substitute.
• 6AL3, EY88 Television "Damper/ Efficiency" Diode
• 6AL5, EAA91, D77 Dual Diode, Detector. Often used in vacuum tube volt meters (VTVMs). Miniature version of type 6H6.
• 6AL6-G Beam power tube for early television use. Same as type 6L6-G, but with scrambled pinout and plate connected to top cap.
• 6AL7-GT Tuning indicator used in many early AM/FM Hi-Fi radios. Similar in function to "Magic Eye" tubes. Has two bar-shaped shadows; one grows to indicate signal strength, the other moves to indicate center tuning on FM.
• 6AM6, EF91, Z77, M8083 Sharp Cutoff R.F. pentode used in receiver front ends and test gear such as VTVMs and Television broadcast modulation monitors.
• 6AN7 Triode-Hexode Local Oscillator/Mixer (used in Australian Radiograms)
• 6AQ5 Beam-power pentode, 7-pin miniature similar of type 6V6.
• 6AQ8 Dual Triode with internal shield, like 6BK7/6BQ7/6BZ7
• 6AR8, 7360, E80T An unusual tube described as a beam deflection tube, used as balanced modulator or mixer with very linear qualities.^[5]
• 6AS6, Pentode with fine-pitch suppressor grid which could serve as a second control grid. Used in radar phantastron circuits.
• 6AS7, 6080 Dual low-mu Triode, Low Impedance
• 6AT6 Dual Diode, High Mu Triode, miniature version of type 6Q7. Triode amplification factor: 70.
• 6AU4 Television "Damper/ Efficiency" Diode
• 6AU6A, EF94 Sharp-cutoff pentode
• 6AV6 Dual Diode, High Mu Triode, miniature version of type 75. Triode amplification factor: 100. (Triode section similar in characteristics to one half of a 12AX7.)
• 6AX4 Television "Damper/ Efficiency" Diode
• 6AX5 Full-wave rectifier. Octal base. Similar in structure to type 6X5, but with higher voltage and current ratings which are comparable to those of types 5Y3 and 80.
• 6B6-G Double-Diode High Mu Triode. Octal version of type 75. Has top-cap connection for triode grid. Later octal version, type 6SQ7, has under-chassis connection for triode grid. Miniature version: 6AV6.
• 6B7 and 6B8 (EBF32): Double-Diode, Semi-Remote Cutoff Pentodes. Based on type 2B7 which had a 2.5 volt heater. Type 6B7 has a UX7 base with a top-cap connection for the control grid (grid 1). Type 6B8 has an octal base with a top cap. The diode plates are most commonly used as (second) detectors and AVC rectification in superheterodyne receivers. Because their control grids have both sharp cutoff and remote cutoff characteristics, these types were used as I.F. amplifiers with AVC bias to the control grid, and as A.F. amplifiers. These types were also used in reflex radios. In a typical 2B7/6B7/6B8 reflex circuit, the I.F. signal from the converter is injected into the pentode and is amplified. The diodes then act as detectors, separating the A.F. signal from the R.F. signal. The A.F. signal is then re-injected into the pentode, amplified, and sent to the audio output tube.^[6]
• 6BA6, EF93, W727, 5790 Medium Cutoff R.F. Pentode (Often encountered in Car Radios)
• 6BE6, EK90, 5750, X727 Pentagrid Converter (Often encountered in Car Radios)
• 6BF6, Dual Diode, Medium-mu triode. Miniature version of octal type 6R7.
• 6BK4 High Voltage beam Triode (30Kv Anode Voltage) Used as shunt regulator in color TV receivers and measurement equipment such as high voltage meters
• 6BK7 Dual Triode with Internal shield between each section, used in RF circuits (Similar to 6BQ7)
• 6BK8, EF86, Z729 Audio Pentode used in microphone pre-amps and audiophile gear
• 6BL8, ECF80 General purpose Triode pentode used in television, audio and test gear
• 6BM8, ECL82 Triode pentode used as the driver and output stages in audio amplifiers, audio output and vertical output stages in televisions and has even been seen in an electronic nerve stimulator.
• 6BN6, Pentode beam-deflection tube used in radar, dual channel oscilloscopes and F.M. demodulators.
• 6BQ6-GT, Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV sets of the 1950s. Most commonly used in sets with diagonal screen sizes less than 19 inches (49 cm). (However, may be found in some larger models.) Larger sets often used similar type 6DQ6. Later versions of this tube branded as 6BQ6-GTB/6CU6.
• 6BU8 Split Anode Television Sync Separator
• 6BQ5, EL84, N709 Beam-power pentode
• 6BX6, EF80, E80F Sharp Cutoff R.F. Pentode (Used in Australian TV 39 MHz I.F. Strips and seen in Wien Bridge audio oscillator), E80F used in early computers.
• 6BY7, EF85, W719 Remote Cutoff R.F. Pentode (Used in Australian TV 39 MHz I.F. Strips)
• 6BZ6 Sharp Cutoff R.F. Pentode used in video I.F. circuits of the 1960s.
• 6BZ7 Dual Triode. See 6BK7
• 6C4 V.H.F. Triode
• 6C6 Sharp Cutoff R.F. Pentode. Most common commercial uses were as a tuned R.F. amplifier, a detector, and an A.F. amplifier. Also used in test equipment. Has UX6 base with top cap. Based on type 57, which had a 2.5 volt heater. Similar to types 1603, 77 and octal types 6J7 and 6SJ7.
• 6C19(This is not an American device number)
• 6CA4, EZ81 Full Wave Rectifier (Often used in Australian Radiograms)
• 6CA7, EL34 Audio Power Output Pentode
• 6CB6 Remote Cutoff R.F. Pentode used in video I.F. circuits of the 1950s and early 1960s.
• 6CG7 Dual Triode (used in television and some audio amplifiers including modern solid-state designs often as a cathode follower, similar to 6SN7)
• 6CJ6 Line Output Pentode
• 6CL6 Power pentode
• 6CM5, EL36, EL360 Audio and Television Line Output Beam Power Tetrode.
• 6CW4 Nuvistor tube, high μ triode
• 6D6 Remote-Cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Has UX6 base with top cap. Based on type 58, which had a 2.5 volt heater. Similar to type 78. Octal version: 6U7-G.
• 6D8-G Superheterodyne Pentagrid Converter, similar to type 6A8. Octal base with top cap. Has 150 ma heater. Used in pre-war 6-volt farm radios.
• 6DA6, EF89 R.F. Pentode used in AM/FM radios manufactured outside North America.
• 6DJ8, ECC88, E88CC, 6922, 6N23P, 6N11 Dual Audio and R.F. Triode (often used in television broadcast equipment, test gear, oscilloscopes and audiophile gear) similar to 6ES8
• 6DQ6, Beam Power Pentode, used as a Horizontal Deflection Output tube in monochrome TV sets of the 1950s. Most often found in sets with diagonal screen measurements larger than 17 inches (43 cm). Smaller sets often used similar type 6BQ6-GT. Also used as Audio Output tubes in Standel guitar amps. Later versions branded as 6DQ6-B/6GW6.
• 6DR8, EBF83, R.F. pentode which will operate with 12v anode supply, used as I.F. amplifier in car radios which run directly off the 13.5 volt supply.
• 6DS4 Nuvistor R.F. triode used in TV tuners immediately prior to the introduction of solid state tuning circuits. (RCA TVs equipped with a 6DS4 tuner bore the trademark "Nu-Vista Vision".)
• 6DS8, ECH83, Triode-Heptode Local oscillator-Mixer which will operate with 12v anode supply, used in car radios which run directly off the 13.5 volt supply.
• 6DT6 Quadrature detector used in TV audio circuits of the 1950s and early 1960s.
• 6DX8 Triode pentode
• 6E5 "Magic Eye" Tuning indicator. Has incorporated driver triode with sharp-cutoff grid which makes it extremely sensitive to any changes in signal strength. Has UX6 base. Based on type 2E5, which had a 2.5 volt heater.
• 6EM5 Pentode (Television Vertical Output)
• 6ES6, EF98, R.F. pentode which will operate with 12v anode supply, used as tuned R.F. amplifier in car radios which run directly off the 13.5 volt supply.
• 6ES8, ECC89, E89CC Dual Triode used as cascode R.F. amplifier in television tuners and V.H.F. receiver front ends, also used as general purpose dual triode in test gear, similar to 6DJ8
• 6F5 High-mu triode, equal to triode section of type 6Q7
• 6F6, KT63 Power Pentode. Octal base version of type 42. Moderate power output rating—9 watts max. (single-ended Class A circuit); 11 watts max. (push-pull Class A circuit); 19 watts max. (push-pull Class AB₂ circuit). Available in metal (numbered "6F6"), shouldered glass ("6F6-G"), and cylindrical glass ("6F6-GT"). Sometimes used as a transformer-coupled audio driver for types 6L6-GC and 807 when those tubes were used in Class AB₂ or Class B amplifiers. Also used as a Class C oscillator/amplifier in transmitters.
• 6F7 Remote Cutoff Pentode, Medium-mu Triode. Has UX7 base with top-cap connection for the pentode's control grid (grid 1). Most common uses were as superheterodyne mixer ("first detector") and local oscillator, or as a combination I.F. amplifier (pentode) and (second) detector or A.F. amplifier (triode). Octal version: 6P7-G.
• 6G5 "Magic Eye" Tuning indicator. Has incorporated triode with remote-cutoff grid, which makes it less reactive to low-level changes in signal strength. Has UX6 base. Electronically identical to type 6U5 except for indicator. Both types had "pie wedge" shadow indicators. At first, the shadow indicator for type 6G5 was fully closed at zero signal and opened as signal strength increased. For type 6U5, the shadow indicator was fully open at zero signal and closed as signal strength increased. After World War II, type 6G5 was discontinued as a unique tube and all 6U5s were doubled branded either as 6G5/6U5 or 6U5/6G5.
• 6G6-G Power pentode. Octal base. Low power output—1.1 watt max. output. Has 150 ma heater. Used in pre-war 6-volt farm radios. Miniature version -- 6AK6.
• 6G8-G Double-Diode Sharp Cutoff Pentode (Used as Detector and first A.F. stage in Australian 1940s radios)
• 6GK5 Miniature V,H.F. Triode (Used as V.H.F. local oscillator in some T.V. Turret Tuners)
• 6GV8, ECL85 Triode Pentode(Used in Vertical Output stages in Australian 1960s TVs)
• 6GW8, ECL86 Audio Triode Pentode (Used in Australian P.A. Amplifiers and Audio/Vertical Output stages in TVs)
• 6H6, D63, EB34, OSW3109. Dual Diode. Octal base. Most commonly found as a "stubby" metal envelope tube. Glass versions 6H6-G and 6H6-GT are also found.
• 6J5, L63. Medium-mu triode.
• 6J7, EF37. Sharp Cutoff Pentode. Most common commercial uses were as a tuned R.F. amplifier, a (second) detector, or an A.F. amplifier. Octal version of type 77. This type included a top-cap connection for the control grid. Later version, type 6SJ7, had its control grid connection on pin 4.
• 6J8-G Triode-Heptode (Local Oscillator/Mixer used in Australian 1940s radios, also used extensively by Philco and Silvertone in the US)
• 6K6-G Power Pentode, octal version of type 41. Low-to-moderate power output rating—0.35 to 4.5 watts (single-ended Class A circuit); 10.5 watts max. (push-pull Class A circuit).
• 6K7, EF39. Remote Cutoff R.F. pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 78. This type included a top-cap connection for the control grid. Later version, type 6SK7, had its control grid connection on pin 4.
• 6L5-G, Medium-mu triode (Similar to type 6J5-G, available only in ST shape)
• 6L6, EL37 High-powered beam-power pentode. There are several variations. Except for types 6L6-GC and 6L6-GX, all have the same maximum output ratings—11.5 watts (single-ended Class A circuit); 14.5 watts (push-pull Class A circuit); 34 watts (push-pull Class AB₁; 60 watts (push-pull Class AB₂ circuit). Types 6L6 and 25L6 were introduced in 1935 as the first beam-power pentodes. Both types were branded with the L6 ending to signify their (then) uniqueness among audio output tubes. However, this is the only similarity between the two tubes. (Type 6W6-GT is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.)
  • 6L6 (metal envelope) and 6L6-G (shouldered glass envelope) were used in pre-World War II radios and Public Address amplifiers.
  • 6L6-GA Post-war version of type 6L6-G, in smaller ST-14 shape.
  • 6L6-GB Post-war improved version in a cylindrical glass envelope. Similar to type 5881.
  • 6L6-WGB "Industrial" version of type 6L6-GB.
  • 6L6-GC Final and highest-powered audio version of the tube. Max. outputs—32 watts (single-ended Class A circuit); 17.5 watts (push-pull Class A circuit); 55 watts (push-pull Class AB₁ circuit); 60 watts (push-pull Class AB₂ circuit)
  • 6L6-GX Class C oscillator/amplifier used in transmitters. Max. output—30 watts. (All versions may be used as a Class C oscillator/amplifier, but this version is specifically designed for this purpose, has a special ceramic base.)
• 6L7 Pentagrid Mixer often used in console radios of the late 1930s. Similar in structure to pentode-triode pentagrid converters 6SA7 and 6BE6, except that a separate oscillator—usually type 6C5 -- is required. Also, grid 1 is remote cutoff control grid, grid 3 is oscillator input grid. (In types 6SA7 and 6BE6, grid 1 is the internal oscillator grid, grid 3 is the control grid.) Because of low conversion transconductance, radios using type 6L7 typically have either a tuned RF pre-amplifier stage, or at least two stages of I.F. amplification. (A few models have both.)
• 6M5 Audio Output Pentode (Used as Class A or C output stages of 1950s Australian radiograms) similar to 6BQ5
• 6N3, EY82 Half-Wave Rectifier
• 6N7, Twin Power Triode, used as Class A audio driver or as Class B power output (also 6N7-G and 6N7-GT). Max. output (Class B) -- 10 watts. Octal version of type 6A6.
• 6N8, EBF80 Remote cut-off pentode, duo-diode. Used as R.F. of A.F. amplifier and detector on Australian mantel radios and radiograms.
• 6P5-G/GT, Medium-mu triode, Octal version of type 76, often used as driver for type 6AC5-G.
• 6P7-G Rarely seen octal version of type 6F7.
• 6Q5-G Triode gas thyratron used in DuMont oscilloscopes as a sweep generator. Identical to RMA type 884.
• 6R3, EY81 Television "Damper/ Efficiency" Diode
• 6R7, Dual Diode, Medium-mu Triode (also 6R7-G and 6R7-GT). Octal base with top cap. Miniature version -- 6BF6. Amplification factor: 16.
• 6S7-G, Remote Cutoff RF Pentode, similar to type 6K7. Octal base with top cap. Has 150 ms heater. Used in pre-war 6-volt farm radios.
• 6S8-GT, Triple Diode, High-mu Triode. Octal tube with top-cap connection to triode grid. Has three identical diodes—two diodes share a cathode with the triode, one has an autonomous cathode. Used as a combined AM detector/AVC rectifier/FM ration detector/A.F. amplifier in AM/FM radios. Typically, all sections of this tube are arranged around a single heater.
• 6SA7 First pentode-triode style pentagrid converter. Octal type. Miniature version: 6BE6.
• 6SC7, High-Mu duo triode (Both sections share a single cathode)
• 6SK7 Remote-cutoff pentode (Used in I.F. stages of North American radios) Miniature version: 6BD6
• 6SL7, ECC35. Twin triode (Used in Television and general electronics)
• 6SN7, ECC32, B65, 13D2, CV1986, 6042? Medium-mu twin triode (Used in Audio Amplifiers, Hammond Organs and Television; extensive use in World War II radar) Each section is equivalent to a 6J5. Miniature version: 12AU7
• 6SS7, Remote cutoff pentode (150ma filament version of the 6SK7, found in some AA6 radios as both the RF amp and first IF). This is the only tube to have two of the same letters in its type.
• 6T5 "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has UX6 base. Shadow indicator is fully closed at zero signal. As signal increases, shadow grows outward from the center, covering the entire circumference of the indicator. Electronically identical to types 6G5 and 6U5, which may be used as substitutes.
• 6T7-G Dual diode, high-mu triode, similar to type 6Q7. Octal base with top cap. Has 150 ma heater. Used in pre-war 6-volt farm radios.
• 6T8 Triple Diode, High-mu Triode. Has three identical diodes—two have cathodes connected to the triode's cathode, one has an autonomous cathode. Triode amplification factor: 70. Used as an AM detector/AVC rectifier/FM ratio detector/A.F. amplifier in North American AM/FM radios. Identical to type 6AK8/EABC80, but with a shorter glass envelope.
• 6U5 "Magic Eye" Tuning indicator. Has incorporated driver triode with remote-cutoff grid. Has UX6 base. Has "pie wedge" shadow indicator that is open at zero signal and closes as signal increases. Electronically identical to types 6G5 and 6T5 and may be used as a substitute for those types. After World War II, most new 6U5s were double-branded as either 6G5/6U5 or 6U5/6G5.
• 6U5G "Magic Eye" Tuning indicator with triode, International Octal, (IO), base
• 6U7-G Remote Cutoff R.F. Pentode. Most common commercial uses were as an I.F. amplifier or as a superheterodyne mixer, aka 1st detector. Also used in test equipment. Octal version of type 6D6. Most direct substitute: 6K7. Similar to types 58, 78 and 6SK7.
• 6V6 Beam power tetrode, used in single-ended class A audio output stages of radios and sometimes seen in class B audio amplifiers. (see also: 5V6 and 12V6) Electrically similar to 6AQ5/EL90.
• 6V7-G, Dual Diode, Medium-mu Triode. Octal version of type 85. Amplification factor: 8.3. Similar to type 6R7.
• 6W6-GT Beam power pentode, used most often as a Vertical Deflection Output tube in monochrome TV sets of the 1950s. Can also used as an Audio Output tube. This is the 6.3 volt heater version of types 25L6-GT and 50L6-GT.

• 6X4 (EZ90) and 6X5 (EZ35): Full-wave rectifiers with indirectly heated common cathode. Type 6X4 has a 7-pin miniature base, the 6X5 has an octal base. Based on type 84/6Z4.

“7” prefix loctal tubes

These tubes all have 6.3 volt AC/DC heaters.

• 7A4: Medium-mu triode, loctal version of type 6J5, often numbered 7A4/XXL
• 7A5: Beam power pentode
• 7A6: Dual detector diode, similar to type 6H6
• 7A7: Remote-cutoff pentode, loctal version of type 6SK7.
• 7A8: Octode converter
• 7AB7: Sharp-cutoff pentode
• 7AD7: Power pentode
• 7AF7: Twin medium-mu triode
• 7AG7: Sharp-cutoff pentode
• 7AH7: Remote-cutoff pentode
• 7AJ7: Sharp-cutoff pentode
• 7AK7: Sharp-cutoff, dual control pentode for computer service. Perhaps the first active device specifically designed for computer use.
• 7B4: High-mu triode, loctal version of types 6F5 and 6SF5
• 7B5: Power pentode, loctal version of types 6K6 and 41
• 7B6: High-mu triode, dual detector diodes, loctal version of type 75, similar to types 6AV6 and 6SQ7
• 7B7: Remote-cutoff pentode
• 7B8: Pentagrid converter, loctal version of types 6A7 and 6A8
• 7C4: High frequency diode
• 7C5: Beam power pentode, loctal version of type 6V6
• 7C6: High-mu triode, dual detector diode
• 7C7: Sharp-cutoff pentode
• 7E5: Medium-mu high-frequency triode
• 7E6: Medium-mu triode, dual detector diode, loctal version of types 6R7 and 6SR7, electronically identical to miniature type 6BF6.
• 7E7: Semi-remote-cutoff pentode, dual detector diode, similar to types 6B7 and 6B8
• 7F7: High-mu dual triode, loctal version of type 6SL7-GT
• 7F8: Medium-mu high-frequency triode, used as FM RF amplifier and converter
• 7G7: Sharp-cutoff pentode
• 7G8: Sharp-cutoff twin tetrode
• 7H7: Semi-remote-cutoff pentode
• 7J7: Triode-heptode converter, similar to type 6J8-G
• 7K7: High-mu triode, dual detector diode, similar to types 6AT6 and 6Q7
• 7L7: Sharp-cutoff pentode
• 7N7: Twin medium-mu triode, loctal version of type 6SN7-GT
• 7Q7: Pentagrid converter, similar to type 6SA7
• 7R7: Remote-cutoff pentode, dual detector diode
• 7S7: Triode-heptode converter
• 7T7: Sharp-cutoff pentode
• 7V7: Sharp-cutoff pentode
• 7W7: Sharp-cutoff pentode
  • Note: Types 7V7 and 7W7 are electronically identical except for base connections of pins 4, 5 and 7. On type 7V7, the suppressor grid (grid 3) is connected to pin 4, an internal shield is connected to pin 5, and the cathode is connected to pin 7. On type 7W7, the suppressor grid and internal shield are connected to pin 5, and the cathode is connected to pins 4 and 7. All other pin connections are the same. If interchanging these tube types is necessary, confirm that pins 4 and 7 are connected at the socket. (Pin 5 is usually connected to the chassis.)
• 7X6: Dual rectifier diode
• 7X7: High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amp, often numbered 7X7/XXFM
• 7Y4: Dual rectifier diode
• 7Z4: Dual rectifier diode

12 volt heater/filament tubes

• 12A5 Power pentode. UX7 base. Single-section tube with two side-by-side 6.3 volt heater-cathode structures. Each is connected together to form (1) a 12.6 volt 300 ma heater for series heater strings, or (2) a 6.3 volt 600 ma heater for parallel heater circuits. Mostly used in pre-war car radios.
• 12A7 Power pentode, rectifier diode. Pentode section is similar to type 38. Diode has a low power rating—120 volts, 30 ma—that limits the number of tubes that can be tied to its B+ circuit. Used in one-tube portable phonographs and a few two- and three-tube radios. Forerunner of such types as 32L7-GT, 70L7-GT and 117L7-GT. UX7 base with top cap. Not related to types 2A7 and 6A7.
• 12AL5, Duo diode (similar to 6AL5 except for heater)
• 12AT6, duo diode/triode (Commonly replaced by 12AV6 in consumer radios)
• 12AT7, ECC81, 6060, B309, M8162 High-mu twin triode
• 12AU7, ECC82, 6067, B329, M8136 Medium-mu twin triode
• 12AV7 Dual Triode
• 12AV6 Twin diode/High-mu triode (see also: 6AV6)
• 12AX7, ECC83, 6057, B327, M8137 High-mu twin triode
• 12AY7 Dual Triode
• 12BA6 Remote cutoff pentode (See also: 6BA6)
• 12BE6 Pentagrid converter (See also: 6BE6)
• 12BH7 Dual Triode
• 12BY7 Video Amplifier Pentode
• 12DT6 Sharp cutoff pentode
• 12DW7 Dissimilar Triodes (also known as 7247 or ECC832)
• 12K5 Tetrode, one of a few tubes that can function with low plate voltages (See Space charge)
• 12SA7, Pentagrid converter (Octal version of 12BE6)
• 12SK7, Remote cutoff Penode (Octal version of 12BA6)
• 12SQ7, Dual diode, triode (Octal version of 12AV6)
• 12Z3, Half-wave rectifier, UX4 base
• 5751 - low voltage low-noise avionics tube

“14” prefix Loctal Tubes

These tubes all have 12.6 volt AC/DC heaters

• 14A4: Medium-mu triode, loctal version of type 12J5
• 14A5: Beam power pentode
• 14A7: Remote-cutoff pentode, often numbered 14A7/12B7
• 14AF7: Twin medium-mu triodes, often numbered 14AF7/XXD
• 14B6: High-mu triode, dual detector diode, similar to types 12AV6 and 12SQ7
• 14B8: Pentagrid converter, loctal version of type 12A8
• 14C5: Beam power pentode, loctal version of type 12V6-GT
• 14C7: Sharp-cutoff pentode
• 14E6: Medium-mu triode, dual detector diode, loctal version of 12SR7
• 14E7: Semi-remote-cutoff pentode, dual detector diode, similar to type 12C8
• 14F7: High-mu dual triode, loctal version of type 12SL7-GT
• 14F8: Medium-mu high frequency triode, used as FM RF amplifier and converter
• 14H7: Semi-remote-cutoff pentode
• 14J7: Triode-heptode converter
• 14N7: Twin dual medium-mu triode, loctal version of type 12SN7-GT
• 14Q7: Pentagrid converter, similar to type 12SA7
• 14R7: Remote-cutoff pentode, dual detector diode
• 14S7: Triode-heptode converter
• 14W7: Sharp-cutoff pentode
• 14X7: High-mu triode, dual detector diodes on separate cathodes, used as FM discriminator and AF amp
• 14Y4: Dual rectifier diode

25 volt heater/filament tubes

• 25A6 Power pentode, octal version of type 43
• 25C5 Beam Power Pentode (Identical to the 50C5 but with a 25V 300ma filament)
• 25F5 Beam Power Pentode (Identical to the 50C5, but with a 25V 150ma filament, used in some AA5 type radios using push-pull output)
• 25L6 Beam-power pentode (Except for heater, electronically identical to type 50L6)
• 25Z5 Twin rectifier diode
• 25Z6 Octal version of 25Z5

35 volt heater/filament tubes

• 35A5 Beam Power Tube (Loctal, Similar to 35L6)
• 35B5 Beam power tube
• 35C5 Identical to 35B5 except for basing ("pin-out") arrangement (HL92)
• 35HB8 Triode/Beam Power tube (Used primarily as both the audio amp and output)
• 35DZ8 High-Mu Triode/Beam Power tube (Like the 35HB8, used for audio)
• 35L6-GT Beam power pentode similar to, but not electronically identical to, types 25L6-GT and 50L6-GT
• 35W4 Rectifier diode
• 35Z4-GT Rectifier diode
• 35Z5-GT Similar to 35Z4-GT, but equipped with a heater tap used to power a pilot light
• 35Z3 Rectifier Diode (Loctal, Similar to 35Z4)
• 35Y4 Rectifier Diode (Loctal, similar to 35Z5)

50 volt heater/filament tubes

• 50B5 Beam power tube, similar to 35B5 but with 50 volt filament
• 50C5 Similar to 35C5 but with 50 volt filament, and 50B5 except for basing ("pin-out") arrangement (HL92)
• 50EH5 Beam Power tube, (Similar to 50C5 but with higher gain, some radios that use this tube do not have an audio amp section.)
• 50L6 Beam power tube (see also 25L6)
• 50HK6 Power pentode (Filament is tapped for use with a dial lamp)
• 50A5 Beam Power Tube (Loctal, similar to 50L6)
• 50X6 Dual Diode (Loctal, commonly used as a rectifier-doubler)
• 50DC4 Rectifier diode (Similar to 35W4 except for filament)

117 volt heater tubes

All of the following tubes are designed to operate with their heaters connected directly to the 117 volt (now 120 volt) electrical mains of North America. All of them use indirectly heated cathodes. All of them incorporate at least one rectifier diode.

• Rectifier diode – Beam power pentode combinations
  • 117L7GT
  • 117M7GT
  • 117N7GT
  • 117P7GT
• Rectifier tubes
  • 117Z3 Single diode, 7-pin miniature version of 117Z4GT
  • 117Z4GT
  • 117Z6GT Dual diode, can be used as a voltage doubler

Shielded tubes for Majestic radios

In the early 1930s, the Grigsby-Grunow Company—makers of Majestic brand radios—introduced the first American-made tubes to incorporate metal shields. These tubes had metal particles sprayed onto the glass envelope, copying a design common to European tubes of the time. Early types were shielded versions of tube types already in use. (The shield was connected to the cathode.) The Majestic numbers of these tube types, which are usually etched on the tube's base, have a "G" prefix (for Grigsby-Grunow) and an "S" suffix (for shielded). Later types incorporated an extra pin in the base so that the shield could be connected directly to the chassis.

Replacement versions from other manufacturers, such as Sylvania or General Electric, tend to incorporate the less expensive, form-fitting Goat brand shields that are cemented to the glass envelope.

Grigsby-Grunow did not shield rectifier tubes (except for type 6Y5 listed below) or power output tubes.

• Early types based on existing tubes. (Non-shielded versions may be used, but add-on shielding is recommended.)
  • G-2A7-S Pentagrid converter
  • G-2B7-S Semiremote cutoff pentode, dual detector diode
  • G-6A7-S Pentagrid converter
  • G-6B7-S Semiremote cutoff pentode, dual detector diode
  • G-6F7-S Remote cutoff pentode, medium-mu triode
  • G-25-S Medium-mu triode, dual detector diode for 2.0 volt storage battery radios. Glass type 1B5/25S used for replacement.
  • G-51-S Remote cutoff tetrode
  • G-55-S Medium-mu triode, dual detector diode
  • G-56-S Medium-mu triode
  • G-56A-S Medium-mu triode, original version of type 76, but with 400 milliampere heater. (Not to be confused with types 56 or G-56-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-57-S Sharp cutoff pentode
  • G-57A-S Sharp-cutoff pentode, original version of type 6C6, but with 400 milliampere heater. (Not to be confused with types 57 or G-57-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-58-S Remote cutoff pentode
  • G-58A-S Remote-cutoff pentode, original version of type 6D6, but with 400 milliampere heater. (Not to be confused with types 58 or G-58-S, which has a 2.5 volt, 1.0 ampere heater.)
  • G-85-S Similar to G-55-S, but with 6.3 volt heater.
• Later types
  • 6C7 Medium-mu triode, dual detector diode, similar to later octal types 6R7 and 6SR7. Seven pin base. (Shield to pin 3.)
  • 6D7 Sharp cutoff pentode, identical to type 6C6, but with 7-pin base. (Shield to pin 5.)
  • 6E7 Remote cutoff pentode, identical to type 6D6, but with 7-pin base. (Shield to pin 5.)
  • 6Y5 Dual rectifier diode, similar to type 84/6Z4, but with 6-pin base. (Shield to pin 2.)

• Other tubes unique to Majestic radios
  • G-2-S and G-4-S Dual detector diodes with common cathodes. The first detector diodes packaged in a separate tube. Forerunners of octal type 6H6. Spray-shielded. Both tubes have 2.5 volt heaters. G-2-S is larger and has a 1.75 ampere heater. Type G-4-S has a 1.0 ampere heater. Later Sylvania replacement type 2S/4S has a 1.35 ampere heater.
  • 2Z2/G-84 Half-wave rectifier diode with 2.5 volt indirectly heated cathode. A lower-voltage version of type 81. Not interchangeable with type 6Z4/84.
  • 6Z5 Full-wave rectifier, similar to types 6Z4/84 and 6X5, but with 12.6 volt center-tapped heater.

Lettered loctal tubes used in Philco radios

• FM-1000 Unusual combined pentagrid oscillator and FM quadrature detector. Manufactured by Sylvania and used in Philco AM/FM radios of the late 1940s and early 1950s.
• XXB Medium-mu twin triode, also numbered 3C6/XXB
• XXD Medium-mu twin triode, also numbered 14AF7/XXD
• XXFM High-mu triode, dual diode (one shares its cathode with the triode, one with separate cathode), also numbered 7X7/XXFM
• XXL Medium-mu triode, also numbered 7A4/XXL

Other tubes with nonstandard filament voltages

The tubes in this list are most commonly used in series-wired circuits.

• 7KY6: sharp cutoff pentode with a 7.3 volt nominal heater voltage, 9 pin miniature socket ^[7]
• 7AU7: Medium-Mu Duo triode with a tapped filament like its more common brother, the 12AU7. 7.0/3.5V
• 11DS5: Beam Power tube (11v filament version of the 50B5/35B5)
• 10DE7: Duo triode (dissimilar triode sections)
• 8FQ7/8CG7: Duo triode (8v version of the common 8CG7)
• 34GD5: Beam power tube (34v version of the 35C5/50C5)
• 36AM3: Half-wave rectifier (36v version of the 35W4)
• 18FY6: Duo diode/triode (18v version of the 12AV6)
• 18FX6: Pentagrid converter (18v version of the 12BE6)
• 4CB6: Sharp cutoff pentode

European designation (with American equivalents)

Most of these tubes have names which specified their heater voltage, construction, and base, for details see

Mullard-Philips tube designation The KTs (Kinkless Tetrodes) are an exception.

• First letter: heater/filament type:

"A" in the first position refers to 4v heater use.
"D" in the first position refers to 1.4v heater use.
"E" in the first position refers to 6.3v heater use.
"G" in the first position refers to 5.0v heater use.
"H" in the first position refers to 12.6v heater use.
"P" in the first position refers to higher voltage heaters, usually operated in series at constant current of about 300mA.
"U" in the first position refers to higher voltage heaters, usually operated in series at constant current of about 100mA.

• Second (and possibly subsequent) letters: diode/triode/etc...

"A" in the second position refers to signal level "Diode".
"B" in the second position refers to two signal level "Diodes".
"C" in the second position refers to "Triode".
"F" in the second position refers to "small signal Pentode".
"L" in the second position refers to "Beam Power Tetrode" or "Power Output Pentode".
"H" in the second position refers to "Special Purpose switching Heptode".
"K" in the second position refers to "Mixer Heptode".
"M" in the second position refers to "Fluorescent Tuning Indicator".
"N" in the second position refers to "Gas Filled Thyrotrons".
"Y" in the second position refers to "Single Power Diode".
"Z" in the second position refers to "Dual, common cathode Power Diodes" or "Full-Wave Rectifier".
A repeat of the second letter means that there are two of the same type of unit in the same bulb or envelope, a different letter in the third placed generally refers to a unit with a different number of grids in the same bulb.

• following digits: model number and base type...

e.g. 30-39 implies an octal base, 80-89 or 180-189 implies a noval base.

EA

• EA50

EAA

• EAA91 (6AL5)

EAB

EABC

• EABC80: High-mu triode, triple diode (two on common cathode with triode, one with independent cathode). Miniature 9-pin used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios. Electronically identical to American types 6T8, 6T8A and 6AK8. (The latter is usually marked 6AK8/EABC80.) Also DH719.

EAF

• EAF42 (6CT7)

EB

• EB91 (6AL5)

EBF

• EBF80 (6N8, WD709)
• EBF83 (6DR8)

ECC

• ECC81 (12AT7, M8162, 6060, B309)
• ECC82 (12AU7, M8136, 6067, B329)
• ECC83 (12AX7, M8137, 6057, B339)
• ECC85 (6AQ8)
• ECC86 (6GM8) Low supply voltage (12-25 V) dual triode
• ECC88 (6DJ8)
• ECC89 (6ES8)
• ECC90 Computer Common cathode dual triode
• ECC91 (6J6) V.H.F. Common cathode dual triode
• ECC92 Computer Common cathode dual triode
• ECC180 Computer dual triode

(Note:) The ECC85, 88 & 89 differ by the fact they do not have centre tapped heater arrangement and are therefore not 'pin to pin' compatible with the ECC81, 82 & 83.

ECL

• ECL80 (6AB8)
• ECL82 (6BM8)
• ECL85 (6GV8)
• ECL86 (6GW8)

ECF

• ECF80 (6BL8)
• ECF82 (6U8)

ECH

• ECH21 (X143)
• ECH3 Ct8 Base
• ECH4 Ct8 Base
• ECH33
• ECH35 (X147)
• ECH42 (6CU7)
• ECH81 (6AJ8, X719)

EF

• EF37A
• EF41 (6CJ5, 62VP)
• EF50
• EF55
• EF80 (6BX6, Z152)
• EF85 (6BY7, W719)
• EF86 (6BK8, Z729, 6267)
• EF89 (6AD6)
• EF90(6BA6?)
• EF91 (6AM6, Z77, M8083, 6064, 8D3)
• EF92 (M8161)
• EF95 (6AK5, 5654, 408A, 62H1P, CV4010)
• EF183 (6EH7)
• EF184 (6EJ7)

EK

• EK2(AK2)
• EK32 OCTODE Frequency converter Octal base, 6.3V heater and top cap.
• EK90(6BE6)

EL

• EL2 Ct8 base, grid cap
• EL3 Ct8 base
• EL3G (6V6) "G" denotes an EL3 with an Octal base
• EL33 (6M6G) in parallel filament circuits
• EL34 (6CA7)
• EL36 (6CM5)
• EL37 (6L6)
• EL38 (6CN6)
• EL41 (6CK5, N150)
• EL42 (N151)
• EL80 (6M5)
• EL81 (6CJ6)
• EL82 (6DY5)
• EL83 (6CK6)
• EL84 (6BQ5, N709)
• EL85 (6BN5)
• EL86 (6CW5)
• EL90 (6AQ5, N727)
• EL91 (6AM5, M8082, 709)
• EL95 (6DL5)
• EL821 (6CH6, 6132)

EM

• EM4 Tuning Indicator, Ct8 Base
• EM34 (6CD7)
• EM5 Tuning Indicator, Ct8 Base
• EM81 (6DA5) Tuning indicator, B9A base
• EM84 (6DH7) Tuning indicator, B9A base
• EM87 (CV10407) Tuning indicator, B9A base
• EMM801 Dual, rectangular-band Tuning Indicator

uo

EN

• EN31 Thyratron
• EN81 (2D21) Thyratron

EY

• EY51 (6X2)
• EY80
• EY81 (6R3)
• EY82 (6N3)
• EY88 (6AL3)

EZ

• EZ3
• EZ80 (6V4)
• EZ81 (6CA4)
• EZ90 (6X4)

GZ

• GZ30 (5Z4-G, 5AQ4)
• GZ32 (5V4)
• GZ34 (5AR4)

HA, HB, HD, HF, HL, HY

• HAA91: Dual diode. Miniature 7-pin. Identical to American type 12AL5.
• HABC80: High-mu triode, triple diode (two on common cathode with triode, one with independent cathode). Miniature 9-pin used as an AF amplifier, AM detector and ratio detector in AC-powered post-war European AM/FM radios. Electronically identical to American types 19T8.
• HBC90: High-mu triode, dual diode, all on common cathode. Miniature 7-pin. Identical to American type 12AT6.
• HBC91: High-mu triode, dual diode, all on common cathode. Miniature 7-pin. Identical to American type 12AV6.
• HD94: Sweep beam power pentode (horizontal output). Octal with plate at top cap. Identical to American types 6BQ6GTA/GTB and 6CU6.
• HD96: Sweep beam power pentode (horizontal output). Octal with plate at top cap. Identical to American types 25BQ6GTB and 25CU6.
• HF93: Remote cutoff pentode. Miniature 7-pin. Identical to American type 12BA6.
• HL92: Audio beam power pentode. Miniature 7-pin. Identical to American type 50C5.
• HY90: Half-wave rectifier. Miniature 7-pin. Identical to American type 35W4.

KT

KT stands for "Kinkless Tetrode - They are in fact Beam Tetrodes

Note: This is not a Mullard designation. They were first manufactured in the UK by MOV (Marconi Osram Valve) subsidiary of GEC in the late 1930s.

• KT32 (25L6, 25L6G, 25L6GT and 25W6GT)
• KT33 (25A6GT)
• KT41
• KT61 (6M6G) in parallel filament circuits
• KT63 (6F6, 6F6G, 6F6GT)
• KT66 (6L6GC)
• KT71 (50L6GT)
• KT77 Similar to EL34, 6CA7
• KT81
• KT88 (6550A, CV5220, 12E13, 7D11)
• KT90

Other Roman Letter Types

A

• ABC1 Sharp Cutoff Pentode, 1930s European radios.
• AK1 Pentagrid Converter, 1930s European radios. UX7 Base.
• AK2 Pentagrid Converter, 1930s European radios. Ct8 Base.
• AL2 Audio Output Pentode, 1930s European radios. Ct8 Base.
• ACT9 Medium sized British Transmitting Triode.

C

• CF1 Sharp Cutoff Pentode, 1930s European radios.

D

• D1 Early directly heated triode used in 1920s T.R.F. and regenerative radios.

E

• EK2 Pentagrid converter, similar to AK2, Ct8 Base.

M

• MT7A, MT7B Large radiation-cooled triodes made by the Marconi Valve Co, (M.O. Valve Co) and used in the 1930s.

P

• PA12/20 Large water cooled Pentode made by Philips and used in the 1930s and 40s.
• PX4 British Audio Output Triode designed by Marconi-Osram in the 1930s. Capable of providing about 4.5W of audio.
• PL36 British high voltage high frequency switching pentode valve. Used in TV receivers for line output and/or EHT generation up to c1964. Octal base, anode connection cap on the top of the valve. Last consumer electronics use DECCA series DR101,202,303,404,505,606 monchrome receivers(9)
• PFL200 Dual Pentode valve common in TV receivers, combining a power pentode to drive the picture tube cathode and a small signal pentode generally used a the separator for synchronising pulses(9)
• PCL85 triode - pentode valve, generally used in TV receivers for field timebase, generally as a multivibrator, with the pentode saection doubling as one half of the multivibrator and the power output device(9)
• PCL86 triode - pentode valve, used for audio amplification in European TV receivers

Q

• QQV03-20A a radiation-cooled split-anode tetrode made by Mullard and used in the 1940s, 50s and 60s as a V.H.F. frequency-doubler RF output stage with balanced output.
• QV05-25 a radiation-cooled output beam-tetrode made by Mullard. More commonly known as the famous 807.
• QE05-40 (otherwise known as the 6146) a radiation-cooled output beam-tetrode popular amongst radio amateurs as a final R.F. amplifier.

R

• R Early directly heated triode used by many amateurs in the 1920s.

S

• SY4307A

A power pentode similar to the output beam-tetrode type 807, and made by Standard Telephones and Cables Pty. Ltd.. The SY4307A differs from an 807 by being a directly-heated pentode rather than an indirectly-heated beam-tetrode. Both types are contained in an ST-16 bulb with an anode cap and 5-pin "American" UY base. This device is historically notable because a pair of them in parallel class C was used as the output stage in a transmitter built in secret by Australian soldiers in Japanese-occupied Portuguese Timor during World-War II in 1942. This transmitter, now reconstructed and on display at the Australian War Memorial in Canberra, was called "Winnie the War Winner".

• SU2150 (CV1120) a high-voltage vacuum half-wave rectifier.

T

• TA-4-2000K a large radiation-cooled transmitting triode made by Philips in the 1930s.

U

• UM11 Tuning Indicator made by Telefunken.

X

• X61,X61M British Triode-Heptode, similar to 6J8
• X41 Triode Hexode mixer designed to be a direct plug in replacement for the MX40 Pentagrid converter.

Y

• Y61 Tuning Indicator, similar to 6G5.

Z

• Z77 Sharp cutopff R.F. pentode, similar to 6AM6

European designation, special quality

Vacuum tubes which had special qualities of some sort, very often long-life designs, particularly for computer and telecommunication use, had the numeric part of the designation placed immediately after the first letter. They were usually special-quality versions of standard types. Thus the E82CC was a long-life version of the ECC82 intended for computer and general signal use, and the E88CC a high quality version of the ECC88/6DJ8. While the E80F pentode was a high quality development of the EF80, they were not pin-compatible and could not be interchanged without rewiring the socket(the E80F is commonly sought after as a high quality replacement for the similar EF86 type in guitar amplifiers). The letters "CC" indicated the two triodes and the "F", the single pentode inside these types.

A few special-quality tubes did not have a standard equivalent, e.g. the E55L, a broadband power pentode used as the output stage of oscilloscope amplifiers and the E90CC, a double triode with a common cathode connection and seven pin base for use in cathode-coupled Flip-flops in early computers. The E91H is a special heptode with a passivated third grid designed to reduce secondary emission; this device was used as a "gate", allowing or blocking pulses applied to the first, (control) grid by changing the voltage on the third grid, in early computer circuits (similar in function to the U.S. 6AS6).

Many of these types had gold-plated base pins and special heater configurations inside the nickel cathode tube designed to reduce hum pickup from the A.C. heater supply, and also had improved oxide insulation between the heater and cathode so the cathode could be elevated to a greater voltage above the heater supply. (Note that elevating the cathode voltage above the average heater voltage, which in well-designed equipment was supplied from a transformer with an earthed centre-tapped secondary, was less detrimental to the oxide insulation between heater and cathode than lowering the cathode voltage below the heater voltage, helping to prevent pyrometallurgical electrolytic chemical reactions where the oxide touched the nickel cathode that could form conductive aluminium tungstate and which could ultimately develop into a heater-cathode short-circuit.)

Better, often dual, getters were implemented to maintain a better vacuum, and more-rigid electrode supports introduced to reduce microphonics and improve vibration and shock resistance. The mica spacers used in "SQ" and "PQ" types did not possess sharp protrusions which could flake off and become loose inside the bulb, possibly lodging between the grids and thus changing the characteristics of the device. Some types, particularly the E80F, E88CC and E90CC, had a constricted section of bulb to firmly hold specially-shaped flakeless mica spacers.^[8]

Numbered tubes

Tubes used in 1920s and 1930s radio receivers

• Tubes with 1.1 volt DC filaments and directly heated cathodes, used in 1920s home radios. Filaments powered by 1.5 volt dry cells, plates powered by storage batteries.
  • WD-11 triode/detector

• Tubes with 5.0 volt DC filaments and directly heated cathodes, used in 1920s home radios powered by storage batteries.
  • 00-A Detector triode with a trace of argon. "00-A" is the number used in most tube manuals. Numbers for earlier versions include UX-200-A and CX-300-A (long pins, push-in socket) and UV-200-A (stub pins, bayonet socket).
  • 01-A All-purpose low-mu triode, used as RF amplifier, detector, AF amplifier and power triode. The most popular tube of the 1920s. "01-A" is the number used for replacements manufactured after 1930 and in tube manuals. Numbers for early versions include UX-201-A and CX-301-A (long pins, push in socket) and UV-201-A (stub pins, bayonet socket).

Note: There were four tubes in the "01" series, each with different current ratings for their filaments. Type 01-A was the most commonly used.

Types UV 201 and UX 201 - 1.0 ampere

Type 01-A (UV 201-A, UX 201-A, etc.) - 250 milliampere

Type UX 201-B - 125 milliampere

Type UX 201-C - 60 milliampere

• • 12-A Medium-mu triode, often used as detector, audio driver or audio output, but not as an RF amplifier - "12-A" is number used for replacements manufactured after 1930 and in tube manuals. Also referred to as 112-A. Many early versions are marked UX-112-A or CX-112-A.
  • 40 Medium-mu triode - Early versions numbered UX-240. Introduced in 1927, this was an upgraded version of the "01" series. The "01" series had an amplification factor of 8, while type 40 had an amplification factor of 30. (By comparison, the two AC triodes introduced in the same time period—types 26 and 27—had amplification factors of 8.3 and 9, respectively.) Because this was the highest-amplification triode available, advertising literature of the time lists it as a high-mu triode, although it is now classified as a medium-mu triode. Type 40 had the highest amplification factor of any triode until the introduction in 1932 of diode/triode complex type 2A6, which had an amplification factor of 100. It also had the highest amplification factor of any DC filament triode until the introduction in 1939 of complementary diode/triode complex types 1H5GT (octal) and 1LH4 (loctal), which both had amplification factors of 65.

• Tubes with 2.0 volt DC filaments and directly heated cathodes, used in 1930s home radios powered by storage batteries.
  • 19 Dual power triode—also used in "farm radios" with 6-volt vibrator power supplies.
  • 20 Power triode - Early versions numbered UX-120.
  • 22 Sharp-cutoff tetrode - Early versions numbered UX-222 or CX-322.
  • 25S Dual detector diode, medium-mu triode. Identical to type 1B5. Usually numbered 1B5/25S.
  • 30 Medium-mu triode - Early versions numbered RCA-230 or CX-330. Can also be used as an power triode. An upgraded version of type 01-A.
  • 31 Power triode - Early versions numbered RCA-231 or CX-331.
  • 32 Sharp-cutoff tetrode - Early versions numbered RCA-232 or CX-332.
  • 33 Power pentode - Early versions numbered RCA-233 or C-333.
  • 34 Remote-cutoff tetrode - Early versions numbered RCA-234 or CX-334.
  • 49 Dual-grid power triode, similar to type 46

• Tubes with 3.3 volt DC filaments and directly heated cathodes, used in 1920s home radios powered by dry cells (filaments) and storage batteries (B-plus voltage).
  • V99 Low-mu triode. Except for stub-pin bayonet base and pinout, electronically similar to X99
  • X99 Similar to V99, but with standard pins and different basing arrangement

• Tubes with DC heaters and indirectly heated cathodes
  • 15 Sharp-cutoff pentode, used in "farm radios", in autodyne circuits requiring a separate cathode.
  • 48 Power tetrode, used in 32-volt "farm radios.'" When two are parallel-connected, they can operate with plate and screen voltages as low as 28 volts.

• Tubes with directly heated cathodes, used only with AC power supplies
  • 10 Power triode - Early versions numbered UX-210 or CX-310.
  • 26 Medium-mu triode, used in early AC radio receivers manufactured in the late 1920s - Early versions numbered UX-226 or CX-326.
  • 45 Power Triode - Early versions numbered UX-245 or CX-345.
  • 46 Dual grid power triode - Grids 1 and 2 connected together for use as push-pull Class B outputs, Grid 2 and plate connected together for use as single-tube audio driver.
  • 47 Power pentode - Early versions numbered RCA-247 or C-347.
  • 50 Power triode - Early versions numbered UX-250 or CX-350.
  • 80 Full-wave rectifier (electronically similar to 5Y3-G) - Early versions numbered UX-280 or CX-380
  • 81 Half-wave rectifier - Early versions numbered UX-281 or CX-381.
  • 82 Mercury Vapor full-wave rectifier
  • 83 Mercury Vapor full-wave rectifier
  • 83-v High-vacuum version of type 83

• Tubes with indirectly heated cathodes, used only with AC power supplies. (Except for type 42, all have 2.5 volt heaters.)
  • 24 Sharp-cutoff tetrode - Early versions numbered UY-224 and C-324
  • 24-A an upgraded version of type 24 - Early versions numbered UY-224A and C-324A
  • 27 Medium-mu triode - Early versions numbered UY-227 and C-327. The first North American tube with an indirectly heated cathode, which is necessary for detector circuits in AC powered tube radios.
  • 35 Remote-cutoff tetrode (Commonly branded as 35/51) - Early versions numbered UY-235 or C-335
  • 42 Power pentode, earlier UX6 base version of type 6F6. Except for 6.3 volt heater, similar to 2A5 and 18.
  • 51 Similar to 35 (Commonly branded as 35/51)
  • 53 Dual power triodes (Except for heater, electronically similar to 6A6 and 6N7)
  • 55 Dual-diode, medium-mu triode (Except for heater, electronically similar to type 85)
  • 56 Medium-mu triode (Except for heater, electronically similar to 76)
  • 57 Sharp-cutoff pentode (Except for heater, electronically similar to 6C6 and octal based 6J7, but not to 77)
  • 58 Remote-cutoff pentode (Except for heater, electronically similar to 6D6 and octal based 6U7G, but not to 78)
  • 59 Power pentode

• Tubes with directly heated cathodes, used with AC, DC or home-based storage battery power supplies (1927–1931)
  • 71-A Power triode - "71-A" is number used for replacements manufactured after 1930 and in tube manuals. Also referred to as 171-A. Many early versions numbered UX-171-A or CX-371-A.

• Tubes with indirectly heated cathodes, used with AC, DC, AC/DC or automobile-based storage battery power supplies
  • 1-v Half-wave rectifier
  • 36 Sharp-cutoff tetrode - Early versions numbered RCA-236 or C-336
  • 37 Medium-mu triode - Early versions numbered RCA-237 or C-337
  • 38 Power pentode - Early versions numbered RCA-238
  • 39 Remote-cutoff pentode, often branded as 39/44
  • 41 Power pentode, earlier UX6 base version of octal type 6K6-G.
  • 43 Power pentode, earlier UX6 base version of octal type 25A6.
  • 44 Similar to type 39
  • 75 Dual-diode, high-mu triode. Earlier UX6 base version of octal types 6B6-G and 6SQ7, and 7-pin miniature type 6AV6.
  • 76 Medium-mu triode
  • 77 Sharp-cutoff pentode, earlier UX6 base version of octal type 6J7.
  • 78 Remote-cutoff pentode, earlier UX6 base version of octal type 6K7.
  • 79 Twin power triode, earlier UX6 base version of octal type 6Y7-G.
  • 84 Full-wave rectifier with indirectly heated cathode, often branded as type 84/6Z4. Earlier UX6 base version of octal type 6X5 and 7-pin miniature 6X4.
  • 85 Dual-diode, medium-mu triode, earlier UX6 base version similar to octal types 6R7 and 6SR7 and miniature types 6BF6 and 6BU6.
  • 89 Power pentode

• Rarely used tubes
  • 14 Similar to 24-A but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
  • 17 Similar to 27 but with a 14 volt, 300 milliampere heater. Used in Philco models 46 and 46E
  • 18 Similar to 2A5 and 42 but with a 14 volt, 300 milliampere heater. No known commercial use.
  • 29 Wunderlich detector. Known to have been manufactured by Sylvania.
  • 52 Dual grid power triode similar to types 46 and 49. Has 6.3 volt filament. Most commonly used in early car radios.
  • 64 Sharp-cutoff tetrode (Except for 400 milliampere heater, similar to 36)
  • 65 Remote-cutoff pentode (Except for 400 milliampere heater, similar to 39)
  • 67 Medium-mu triode (Except for 400 milliampere heater, similar 37)
  • 68 Power pentode (Except for 400 milliampere heater, similar to 38)
  • 69 Wunderlich detector
  • 70 Wunderlich detector used in Mission Bell model 19 car radio. Listed in early Philco tube lists.
  • 90 Wunderlich detector
  • 92 Wunderlich detector
  • 95 Original number of type 2A5
  • 181 Power triode
  • 182-B Similar to 482-B below.
  • 183 Similar to 483 below.
  • 213 Early version of type 80 - Often numbered UX-213
  • '216 Early version of type 81 - Often numbered as UX-216-B
  • 482-B Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 182-B/482-B. Similar to type 71-A, but with higher plate voltage.
  • 483 Power triode with directly heated cathode. Used in Sparton AC radios, circa 1929. Replacements often numbered 183/483. Similar to type 45, but with a 5.0 volt, 1.25 ampere heater.
  • 485 Medium-mu triode with indirectly heated cathode. Used in Sparton AC radios, circa 1929. Similar to types 56 and 76, but with a 3.0 volt, 1.25 ampere heater, and lower plate voltage.

• • 950 Power pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to type 1F4.
  • 951 Sharp-cutoff pentode with directly heated cathode, used in storage battery home radios with 2.0 volt filament supply. Similar to type 1B4-P.

Other numbered tubes

2

• 211 A large Triode now favored by Audiophiles.
• 2C39 UHF power triode, "oil can" shape
• 2C43 "Lighthouse" triode for UHF applications

4

• 4-1000A Large glass beam tetrode popular in broadcast and amateur transmitters.
• 4CX250B A forced air cooled ceramic tetrode favored by radio amateurs as a final.

7

• 7189 equivalent to EL84
• 7189A similar to EL84.

8 and higher

• 800 Directly heated V.H.F. power triode, giving 35 watts up to 60 MHz and 18 watts at 180 MHz. American 4-Pin(UX)base with side locating pin.
• 801Directly heated power triode, used in pairs in class B in A.M. modulation sections of transmitters giving up to 45 watts of power at 60 MHz and 22 watts at 120 MHz.
• 802 Indirectly heated H.F. power pentode, giving 8 watts up to 30 MHz and 4 watts at 110 MHz.
• 803 Directly heated H.F. power pentode, giving 50 watts up to 20 MHz and 25 watts at 70 MHz.
• 804 Directly heated H.F. power pentode, giving 20 watts up to 15 MHz and 10 watts at 10 MHz.
• 805 Directly heated H.F. high-mu triode, giving 140 watts up to 30 MHz and 70 watts at 85 MHz..
• 806 Directly heated H.F. high-mu triode, giving 390 watts up to 30 MHz 195 watts at 100 MHz.
• 807 Indirectly heated H.F. beam power tetrode, giving 25 watts up to 30 MHz and 12 watts at 125 MHz. A variation of type 6L6 originally designed as a Class C transmitter tube. Later used in pairs as push-pull outputs for high-wattage Class AB₂ audio amplifiers. Also used as a horizontal output tube in early television receivers. One of the first commercial tubes that used the top cap to connect the plate (instead of the control grid) to the circuit.
• 808 Directly heated H.F. high-mu triode, giving 140 watts up to 30 MHz and 70 watts at 130 MHz.
• 809 Directly heated H.F. high-mu triode, giving 55 watts up to 27 MHz and 30 watts at 100 MHz.
• 810 Directly heated H.F. triode, 10 volt filament and Zirconium Carbide anode. Base fits R.C.A. UT-541A Socket.
• 811A Directly heated H.F. triode, 6.3 volt filament, 88 watts

• 813 Beam Power Tetrode possessing about 5 times the Anode dissipation of an 807.
• 814 A directly heated Beam Power Tetrode giving about 130 watts at 30 MHz and 65 watts at 100 MHz operating in class C.
• 815 An indirectly heated dual Pentode. International Octal, (IO), base.
• 829 A dual indirectly heated beam power tetrode. Two 6.3 volt heaters sharing a common tap.
• 830 A directly heated triode giving about 50 watts at 15 MHz and 7.5 watts at 60 MHz operating in class C.
• 831 A directly heated triode giving about 400 watts at 20 MHz and 200 watts at 60 MHz operating in class C. 11 volt heater/filament.
• 833 A larger directly heated high-mu triode giving about 1Kw at 30 MHz and 500 watts at 45 MHz operating in class C. Usable up to 100 MHz at reduced power, (400w). 10 volt heater/filament drawing 10A. The anode/Plate of this device is fabricated from tantalum. Plate current of 800mA with a plate voltage of 3Kv and grid voltage of zero. Plate current of 4.3A at a voltage of 750 with 350 volts on the grid. Superseded by the 833A. Uses two-part R.C.A socket assembly UT-103.^[9]
• 833A A larger directly heated high-mu triode giving about 1Kw at 30 MHz and 500 watts at 45 MHz and 400 watts at 100 MHz operating in class C. 10 volt heater/filament drawing 10A. The anode/Plate of this device is fabricated from tantalum.
• 834 A directly heated triode giving 58 watts at 100 MHz and 25 watts at 350 MHz operating in class C. 7.5 volt heater/filament. Fitted with an American 4-Pin, (UX4), base with side locating pin.

• 836 An indirectly heated high vacuum diode with a peak inverse voltage of 5Kv and peak anode current of 1 ampere. 2.5 volt heater.
• 837 An indirectly heated pentode giving 11 watts at 20 MHz and 5 watts at 80 MHz. operating in class C. 12.6 volt heater.
• 838 A directly heated triode giving about 100 watts at 30 MHz operating in class C. 10 volt heater/filament.

• 841 A directly heated high-mu triode giving about 10 watts at 6 MHz and 5 watts at 170 MHz operating in class C. 7.5 volt heater/filament.
• 842 A directly heated triode giving about 3 watts at 6 MHz operating in class C. 7.5 volt heater/filament.
• 843 An indirectly heated tetrode giving gain at 6 MHz and usable up to 200 MHz operating in class C. 2.5 volt heater/filament.
• 844 A directly heated triode giving gain at 6 MHz and usable up to 155 MHz operating in class C. 2.5 volt heater/filament.
• 845 A directly heated triode giving up to 24 watts if undistorted power in class-A at audio frequency with an anode voltage of 1250. 11 volt heater/filament.

• 849 A directly heated triode giving gain at 3 MHz operating in class C. Two 849s, working in push-pull class B are capable of delivering 1.1Kw of audio output with an anode voltage of 3Kv. Usable up to 30 MHz. 11 volt filament/heater.
• 850 A directly heated tetrode giving 120 watts of power gain up to 13 MHz and 50 watts at 100 MHz, operating in class C. 10 volt heater/filament.
• 851 A directly heated triode giving 1.5Kw of power up to 3 MHz operating in class C. 11 volt heater/filament.
• 852 A directly heated triode giving 75w of power up to 30 MHz operating in class C. 10 volt heater/filament.
• 857B Large mercury vapor rectifier used in 50 kW class broadcast transmitters. 22kV anode voltage, 10A anode current. Filament 5V@30A

• 860 A directly heated tetrode giving 105w of power up to 30 MHz and 50watts at 120 MHz operating in class C. 10 volt heater/filament.
• 861 A directly heated triode giving 400w of power up to 20 MHz and 200 watts ad 60 MHz operating in class C. 11 volt heater/filament.
• 862 Large water cooled triode for broadcast/industrial applications. Used in experimental 500 kW transmitter at WLW.

• 864 A directly heated general purpose triode with a maximum anode voltage of 135 and anode current of 3.5mA. 1.1 volt heater/filament.
• 865 A directly heated tetrode giving 30w of power up to 15 MHz 15 watts at 70 MHz operating in class C. 11 volt heater/filament.
• 866 A Mercury Vapor Diode with a peak inverse voltage of 5Kv and peak anode current of 1 ampere. Average anode current, 250mA, forward drop, 15 volts. Heater voltage and current, 2.5 at 5A. American 4-Pin(UX) base.
• 866A A Mercury Vapor Diode with a peak inverse voltage of 10Kv and peak anode current of 1 ampere. Average anode current, 250mA, forward drop, 10 volts. Heater voltage and current, 2.5 at 5A. American 4-Pin (UX) base.
• 872 A Mercury Vapor Diode with a peak inverse voltage of 5Kv and peak anode current of 5 amperes. Average anode current, 1250mA, forward drop, 15 volts. Heater voltage, 5.0 at 10A. Base fits R.C.A. UT-541A Socket.
• 872A A Mercury Vapor Diode with a peak inverse voltage of 10Kv and peak anode current of 5 amperes. Average anode current, 1250mA, forward drop, 10 volts. Heater voltage, 5.0 at 6.25A. Base fits R.C.A. UT-541A Socket.
• 879 A high vacuum Diode with a peak inverse voltage of ca. 15Kv and peak anode current of ca. 5mA. 2.5 volt heater and American 4-Pin, (UX) base. Used as half wave rectifier for high voltage cathode ray tube supplies. Similar to type 2X2.
• 884 An indirectly heated triode thyratron. 6.3 volt heater/filament, International Octal, (IO), base. Electrically similar to type 885. Once commonly used as a sawtooth horizontal sweep waveform generator in recurrent-sweep oscilloscopes. Marketed by DuMont under the type number 6Q5.
• 885 An indirectly heated triode thyratron. 6.3 volt heater/filament, American 5-Pin (UY) base. Electrically similar to type 884.
• 898 Large water cooled triode for broadcast/industrial applications. Updated version of 862, with 3 phase filament structure.
• 954 An indirectly heated pentode giving gains of 2-3 up to 300 MHz operating in class A and usable up to 600 MHz with careful stage design. 6.3 volt heater/filament.
• 955 An indirectly heated Triode giving power of 135 mW up to 600 MHz operating in class A and 500 mW in class C with careful stage design. 6.3 volt heater/filament.
• 956 An indirectly heated sharp cut-off pentode giving gains of 3-4 up to 600 MHz operating in class A with careful stage design. 6.3 volt heater/filament.

• 1602 A directly heated triode used for A.F.amplification with low microphonics. 7.5 volt heater/filament. 12 watts of A.F. operating in class A. 15 watts of low R.F. operating in class C. Similar to type 10.
• 1603 An indirectly heated pentode used for A.F. amplification with low microphonics. Similar to types 6U7, 57, 6D6 and 6C6. UX6 Base.
• 1608 A directly heated triode giving 20 watts at up to 45 MHz. 2.5 volt heater/filament. UX base.
• 1609 A directly heated pentode used for A.F. amplification with low microphonics. American 5-Pin(UY)base.
• 1610 A directly heated pentode specially designed for use as a crystal oscillator. 2.5 volt heater/filament, American 5-Pin base.
• 1625 very similar to the 807, but with 12.6V heater instead of 6.3V
• 5654, 6AK5, EF95, CV4010, 62H1P, 408A V.H.F pentode; common in old radar IF amplifiers.
• 5749, 6BA6, EF90?, W727 R.F. pentode
• 5750, 6BE6, EK90, X727 heptode mixer
• 5814A (industrial, computer rated version of 12AU7)
• 6057, 12AX7, ECC83, M8137, B339 high mu double triode
• 6059, 6BR7
• 6060, 12AT7, ECC81, M8162, B309 high mu double triode
• 6064, 6AM6, EF91, M8083, Z77 R.F. pentode
• 6067, 12AU7, ECC82, M8136, B329 medium mu double triode
• 6080, 6AS7 (very low impedance double triode, designed for series regulator applications, now popular for output transformerless audio amplifiers)
• 6146 Power AF/RF pentode
• 6146B (8298A) Improved version of 6146, 6146A and 8298.
• 6550
• 6922 (E88CC, industrial version of 6DJ8/ECC88)
• 6900
• 7308 (E188CC, premium version of 6922)
• 7360 Beam-deflection tube, used as balanced modulator/mixer up to 100 MHz.
• 7JP4 monochrome cathode ray tube common in early postwar TV receivers. Electrostatic deflection, 7" screen.
• 8974 Giant water-cooled megawatt-class tetrode used for super-power broadcast and industrial service. Believed to be the most powerful tube ever commercially produced.

Russian tubes

Main article: Russian tube designations

• 6N1P (similar to 6DJ8/ECC88)
• 6N2P (similar to 12AX7/ECC83)
• 6N3P (2C51)
• 6P1P (similar to 6AQ5/EL90)
• 6P3S (similar to 6L6)
• 6P6S (6V6)
• 6P14P (6BQ5/EL84)
• GU-50

Classes of vacuum tube

• Audion
• Beam-power pentode (beam tetrode)
• Cathode ray tube
• Charactron
• Compactron
• Crookes tube
• Dekatron
• Diode
• Fleming valve
• Iconoscope
• Kinescope
• Krytron
• Klystron
• Loewe 3NF
• Magnetron
• Mercury arc valve
• Miniature valve
• Monoscope
• Nonode
• Pentagrid converter
• Pentode
• Selectron tube
• Storage tube
• Tetrode
• Traveling wave tube
• Triode
• Video camera tube
• Williams tube

Classes of electronic tube containing gas or vapour

• Rectifiers
• Voltage Regulators
• Exitron
• Ignitron
• Thyratron
• Nixie Tube
• Seditron

References

• General Electric Essential Characteristics, 1970
• RCA Receiving Tube Manual (RC-28)
• Sylvania Technical Manual, 1958

1. ^ http://www.tubecollector.org/cv-valves.htm CV valve Registers and information
2. ^ http://homepages.nildram.co.uk/~wylie/CVseries/CVseries.htm The UK military CV series
3. ^ Robert B. Tomer Getting the Most out of Vacuum Tubes, Howard W. Sams Co., Indianapolis, 1960 Library of Congress card number 60-13843(Available on the Internet Archive) Chapter 6 discusses heater voltages as one of the many factors leading to proliferation of tube tyypes.
4. ^ RCA Receiving Tube Manual RC 20
5. ^ [1][2]
6. ^ Schematic for General Electric model F-40, a 1938 reflex radio using a 6B7.
7. ^ RCA Receiving Tube Manual RC-20
8. ^ "Miniwatt" Premium Quality and Special Purpose Tubes, Philips Electrical Industries Pty. Ltd., Australia, November 1957.
9. ^ R.C.A. Air-Cooled Transmitting Tube Manual TT3, R.C.A. Manufacturing Company, Harrison, New Jersey, 1938

• J P Hawker (ed), Radio and television servicing Newnes, 1964

External links

• Vacuum Tube Data Sheet Locator
• Tube Substitution and Characteristics Guide
• NJ7P Tube Data archive
• Radio museum
• Power transmitting tubes
• Large tube chart listing some characteristics and giving access to datasheets for most of them
• British virtual thermionic valve museum with good quality pictures and data
• Frank Philipse's massive Tube Datasheet Archive
• Virtual Valve Museum