The 6DJ8 is a miniature 9-pin medium gain dual 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...

 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 is distinguished by its very high transconductance, mostly the result of its frame grid construction.

Origins

Developed by Amperex

Amperex Electronic

Amperex Electronic Corporation was a manufacturer of vacuum tubes and semiconductors.- Brooklyn, New York :Originally located at 79 Washington Street in Brooklyn, New York, Amperex was a long-established manufacturer of transmitting tubes when they were acquired by the Dutch firm, Philips around 1955...

 in 1958, the 6DJ8 was originally designed for use as a low-noise amplifier in VHF and UHF TV tuners, an improved successor to the usual 6BK7. But its high gain won it many designs in high-end test equipment. Most high-quality oscilloscopes from the 1950s thru the 1960s have many 6DJ8 tubes, often a majority.

Audio

Although not originally designed for the purpose, it became popular in hi-fi audio amplifiers. European-produced version of the tube is designated ECC88. An industrial (improved/higher ratings) version of the tube is designated 6922. New Old Stock (NOS) 6DJ8s and ECC88s produced in the past by major American or West European vacuum tube manufacturers (such as Philips

Philips

Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

 or Amperex) remain extremely popular with and highly sought by audiophiles. A version (direct equivalent) of this tube was also produced in the Soviet Union under the designator 6N23P (Russian: 6Н23П) and in China, under the 6N11 designator.

The tube is currently being produced in four versions in Eastern Europe - Slovakia

Slovakia

The Slovak Republic is a landlocked state in Central Europe. It has a population of over five million and an area of about . Slovakia is bordered by the Czech Republic and Austria to the west, Poland to the north, Ukraine to the east and Hungary to the south...

 by JJ Electronics (ex-Tesla), Serbia

Serbia

Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...

 (Ei) and in Russia - 6DJ8 for Sovtek

Sovtek

Sovtek is a brand of vacuum tube owned by Mike Matthews's New Sensor Corporation and manufactured in Saratov, Russia. They are often used in guitar amplification and include the popular variants of the 12AX7, EL84, EL34, and 6L6 models...

 and 6922 for 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....

.