Guitar amplification tubes

Siemens AG ( ) is a German multinational technology company. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the position of global market leader in industrial AI, automation, and industrial software.

Koninklijke Philips N.V. (), simply branded Philips, is a Dutch multinational health technology and former consumer electronics company that was founded in Eindhoven in 1891. Since 1997, its world headquarters have been situated in Amsterdam, though the Benelux headquarters is still in Eindhoven. The company gained its royal honorary title in 1998.

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Tungsram was a manufacturing company located in Hungary and known for their light bulbs and electronics. Established in Újpest (today part of Budapest, Hungary) in 1896, it initially produced telephones, wires and switchboards. The name "Tungsram" is a portmanteau of tungsten ( ) and wolfram ( ), the two common names of the metal used for making light bulb filaments. Before becoming nationalized by the Communist government in 1945, the company was the world's third largest manufacturer of light bulbs and radiotubes, after the American General Electric and RCA companies.

thumb|A guitar pedal board, comprising several EHX pedals, including a Big Muff, POG (Polyphonic Octave Generator), a Stereo Pulsar tremolo and a Tube EQ.

The EL34 is a thermionic vacuum tube of the power pentode type. The EL34 was introduced in 1955 by Mullard, which was owned by Philips. The EL34 has an octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits; it was also designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. The USSR analog was 6P27S (Cyrillic: 6П27C).

12AX7 (also known as ECC83) is a miniature dual-triode vacuum tube with high voltage gain. Developed around 1946 by RCA engineers in Camden, New Jersey, under developmental number A-4522, it was released for public sale under the 12AX7 identifier on September 15, 1947.

6L6 is the designator for a beam power tube introduced by Radio Corporation of America in April 1936 and marketed for application as a power amplifier for audio frequencies. The 6L6 is a beam tetrode that utilizes formation of a low potential space charge region between the anode and screen grid to return anode secondary emission electrons to the anode and offers significant performance improvements over power pentodes. The 6L6 was the first successful beam power tube marketed. In the 21st century, variants of the 6L6 are manufactured and used in some high fidelity audio amplifiers and musical

thumb|6SN7 vacuum tube dual triode made by Raytheon 6SN7 is a dual triode vacuum tube with an eight-pin octal base. It provides a medium gain (20 dB). The 6SN7 is basically two 6J5 triodes in one envelope.

The EL84 is a vacuum tube of the power pentode type. It is used in the power-output stages of audio amplifiers, most commonly now in guitar amplifiers, but originally in radios. The EL84 is smaller and more sensitive than the octal 6V6 that was widely used around the world until the 1960s. An interchangeable North American type is the 6BQ5 (the RETMA tube designation name for the EL84).

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thumb|6V6 Tube socket|Octal socket basing diagram. 1 - * Unconnected in all versions except for the shell connection of the metal 6V6 2 & 7 - Filament / Heater 3 - Anode / Plate 4 - Grid 2 / Screen Grid 5 - Grid 1 / Control Grid 6 - No connection. Pin normally absent 8 - Cathode & Beam-Forming Plates

280px|thumb|A Sovtek MIG-50 amplifier on top of an SWR Henry 8x8 [[speaker cabinet]] thumb|KT88 vacuum tubes made by 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 versions of the popular 12AX7, EL84, EL34, and 6L6 vacuum tubes. Many of the vacuum-tube amplifiers in modern production are factory-fitted with Sovtek valves. Originally, Sovtek guitar amplifier valves were claimed to have been descendants of earlier wartime Russian-made components and carried blast

The KT88 is a beam tetrode/kinkless tetrode (hence "KT") vacuum tube for audio amplification.

The 12AU7 and its variants are miniature nine-pin (B9A base) medium-gain dual-triode vacuum tubes. It belongs to a large family of dual-triode vacuum tubes which share the same pinout (RETMA 9A). 12AU7 is also known in Europe under its Mullard–Philips tube designation ECC82. There are many equivalent tubes with different names, some identical, some designed for ruggedness, long life, or other characteristics; examples are the US military 5814A and the European special-quality ECC802 and E82CC.

thumb|upright|A Mullard TDD4 valve. The gold spray coating served no purpose other than to hide the blackened interior, as Mullard valves were still manufactured using the azide process, long abandoned by other makers. upright|thumb|A Mullard EL34 power pentode thumb|An EL84 valve made in Russia in the 21st century