EF86
Encyclopedia
EF86 is a miniature high gain, low mu, pentode
vacuum tube
. It has 9 pins and connects to a B9A base.
The EF86 was introduced in the late 1950s and were produced by Philips
, Mullard
, Telefunken
, Valvo, and GEC among others. It is very similar to the octal base
EF37A and the Rimlock base EF40, and was used in many preamplifier
designs during the last decades of vacuum tube
hi-fi development. An industrial variant of the tube is known as 6267. In the former Soviet Union
a variant was also produced as type 6Zh32P (Russian: 6Ж32П.) Currently EF86 are being produced in Russia
in two versions under Electro-Harmonix
brand and in the Slovak Republic under JJ Electronics brand name (former Tesla
).
, 200 mA indirected-heated A.F.
Pentode
in a Noval (B9A) base with an EIA 9CQ (or 9BJ) basing diagram.
Maximum Ratings:
Plate voltage, Va < 300 V
Anode dissipation, Wa <1.0 W
Screen voltage, Vg2 < 200 V
Cathode current, Ik < 6 mA
Special precautions have been taken in the design to reduce:
Compared to other pentode
s, the EF86 is generally much quieter, but compared with some triode
s, the noise (about 2 µV equivalent input noise to 10 kHz) is slightly higher and the microphonics (especially in instrument amplifiers) can be a problem even when mounted in a vibration-reducing valve holder (although it was regularly used in tape recorder input stages, for example).
Special Quality:
Different heater voltage/currents:
http://www.r-type.org/addtext/add036.htm Mullard's EF86 at the National Valve Museum.
http://www.r-type.org/addtext/add008.htm The Mullard EF36, EF37 and EF37A at the National Valve Museum.
http://tdsl.duncanamps.com/show.php?des=EF86 TDSL Tube data: EF86.
http://tdsl.duncanamps.com/sheets/ef86/ef86_01.pdf Datasheet for Thorn/Mazda 6F22/EF86 (pdf).
Pentode
A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid vacuum tube , which was invented by the Dutchman Bernhard D.H. Tellegen in 1926...
vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
. It has 9 pins and connects to a B9A base.
The EF86 was introduced in the late 1950s and were produced by Philips
Philips
Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....
, Mullard
Mullard
Mullard Limited was a British manufacturer of electronic components. The Mullard Radio Valve Co. Ltd. of Southfields, London, was founded in 1920 by Captain Stanley R. Mullard, who had previously designed valves for the Admiralty before becoming managing director of the Z Electric Lamp Co. The...
, Telefunken
Telefunken
Telefunken is a German radio and television apparatus company, founded in Berlin in 1903, as a joint venture of Siemens & Halske and the Allgemeine Elektricitäts-Gesellschaft...
, Valvo, and GEC among others. It is very similar to the octal base
Octal base
Octal base may refer to:*A vacuum tube socket with an eight-pin base*The octal, or base-8, numeral system...
EF37A and the Rimlock base EF40, and was used in many preamplifier
Preamplifier
A preamplifier is an electronic amplifier that prepares a small electrical signal for further amplification or processing. A preamplifier is often placed close to the sensor to reduce the effects of noise and interference. It is used to boost the signal strength to drive the cable to the main...
designs during the last decades of vacuum tube
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
hi-fi development. An industrial variant of the tube is known as 6267. In the former Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
a variant was also produced as type 6Zh32P (Russian: 6Ж32П.) Currently EF86 are being produced in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
in two versions under Electro-Harmonix
Electro-Harmonix
Electro-Harmonix is a New York-based company that makes high-end electronic audio processors. The company was founded by Mike Matthews in 1968. They are most famous for a series of popular guitar effects pedals introduced in the 1970s and 1990s....
brand and in the Slovak Republic under JJ Electronics brand name (former Tesla
Tesla (company)
TESLA was a large, state-owned electrotechnical conglomerate in the former Czechoslovakia....
).
Characteristics
6.3 VoltVolt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...
, 200 mA indirected-heated A.F.
Audio frequency
An audio frequency or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human...
Pentode
Pentode
A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid vacuum tube , which was invented by the Dutchman Bernhard D.H. Tellegen in 1926...
in a Noval (B9A) base with an EIA 9CQ (or 9BJ) basing diagram.
- Transconductance: 2.2 mA/V at Ia=3.0 mA, Ig2=0.6 mA, Va=250 V, Vg1=-2.2 V, Vg2=140 V, Vg3=0 V
- Voltage gain: 185 (45dBDBDB may refer to:In science and technology:*Decibel , a logarithmic unit of measurement in acoustics and electronics*Dubnium , a chemical element*DB connector, a size of D-subminiature electrical connector...
) at Vsupply=250 V, Ik=0.9 mA, Rk=2.2 kilohm, Ra=220 kilohm, Rg1=1 megohm, Vout<44 VRMS
Maximum Ratings:
Plate voltage, Va < 300 V
Anode dissipation, Wa <1.0 W
Screen voltage, Vg2 < 200 V
Cathode current, Ik < 6 mA
Special precautions have been taken in the design to reduce:
- mains humMains humMains hum, electric hum, or power line hum is an audible oscillation of alternating current at the frequency of the mains electricity, which is usually 50 Hz or 60 Hz, depending on the local power line frequency...
(through a bifilar-wound twisted pair of heater wires), - noise, and
- microphonicsMicrophonicsMicrophonics describes the phenomenon where certain components in electronic devices transform mechanical vibrations into an undesired electrical signal...
(through a rigid internal structure to reduce resonances).
Compared to other pentode
Pentode
A pentode is an electronic device having five active electrodes. The term most commonly applies to a three-grid vacuum tube , which was invented by the Dutchman Bernhard D.H. Tellegen in 1926...
s, the EF86 is generally much quieter, but compared with some triode
Triode
A 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. The triode vacuum tube was the first electronic amplification device...
s, the noise (about 2 µV equivalent input noise to 10 kHz) is slightly higher and the microphonics (especially in instrument amplifiers) can be a problem even when mounted in a vibration-reducing valve holder (although it was regularly used in tape recorder input stages, for example).
Similar Devices
- 6267 * Z729 * CV2901 * 6BK8 * 6CF8 * 6F22 * CV8068 * CV10098
Special Quality:
- EF86SQ * M8195 * CV4085 * EF806S
Different heater voltage/currents:
- PF86 (4.5 V/300 mA)
- UF86 (12.6 V/100 mA)
Further reading
https://www.tubeworld.com/6267.htm Tubeworld.com's EF86 page.http://www.r-type.org/addtext/add036.htm Mullard's EF86 at the National Valve Museum.
http://www.r-type.org/addtext/add008.htm The Mullard EF36, EF37 and EF37A at the National Valve Museum.
http://tdsl.duncanamps.com/show.php?des=EF86 TDSL Tube data: EF86.
http://tdsl.duncanamps.com/sheets/ef86/ef86_01.pdf Datasheet for Thorn/Mazda 6F22/EF86 (pdf).