You do not have permission to edit this page, for the following reasons:

This IP address has been blocked from editing Wikipedia.
This does not affect your ability to read Wikipedia pages.
Most people who see this message have done nothing wrong. Some kinds of blocks restrict editing from specific service providers or telecom companies in response to recent abuse or vandalism, and can sometimes affect other users who are unrelated to that abuse. Review the information below for assistance if you do not believe that you have done anything wrong.

The IP address or range 44.195.0.0/16 has been blocked (disabled) by ‪Blablubbs‬ for the following reason(s):

The IP address that you are currently using has been blocked because it is believed to be a web host provider or colocation provider. To prevent abuse, web hosts and colocation providers may be blocked from editing Wikipedia.
You will not be able to edit Wikipedia using a web host or colocation provider because it hides your IP address, much like a proxy or VPN.
We recommend that you attempt to use another connection to edit. For example, if you use a proxy or VPN to connect to the internet, turn it off when editing Wikipedia. If you edit using a mobile connection, try using a Wi-Fi connection, and vice versa. If you are using a corporate internet connection, switch to a different Wi-Fi network. If you have a Wikipedia account, please log in.
If you do not have any other way to edit Wikipedia, you will need to request an IP block exemption.

How to appeal if you are confident that your connection does not use a colocation provider's IP address:
If you are confident that you are not using a web host, you may appeal this block by adding the following text on your talk page: ((unblock|reason=Caught by a colocation web host block but this host or IP is not a web host. My IP address is _______. Place any further information here. ~~~~)). You must fill in the blank with your IP address for this block to be investigated. Your IP address can be determined here. Alternatively, if you wish to keep your IP address private you can use the unblock ticket request system. There are several reasons you might be editing using the IP address of a web host or colocation provider (such as if you are using VPN software or a business network); please use this method of appeal only if you think your IP address is in fact not a web host or colocation provider.

Administrators: The IP block exemption user right should only be applied to allow users to edit using web host in exceptional circumstances, and requests should usually be directed to the functionaries team via email. If you intend to give the IPBE user right, a CheckUser needs to take a look at the account. This can be requested most easily at SPI Quick Checkuser Requests. Unblocking an IP or IP range with this template is highly discouraged without at least contacting the blocking administrator.

This block will expire on 09:46, 11 January 2025.

Even when blocked, you will usually still be able to edit your user talk page, as well as email administrators and other editors.

For information on how to proceed, please read the FAQ for blocked users and the guideline on block appeals. The guide to appealing blocks may also be helpful.

Other useful links: Blocking policy · Help:I have been blocked
Your IP address is in a range that has been blocked on all Wikimedia Foundation wikis. The block was made by ‪AntiCompositeNumber‬. The reason given is Open proxy/Webhost: Visit the FAQ if you are affected .
- Start of block: 13:55, 18 August 2022
- Expiry of block: 13:55, 18 January 2025
Your current IP address is 44.195.68.6. The blocked range is 44.195.0.0/16. Please include all above details in any queries you make. If you believe you were blocked by mistake, you can find additional information and instructions in the No open proxies global policy. Otherwise, to discuss the block please post a request for review on Meta-Wiki. You could also send an email to the stewards VRT queue at stewards@wikimedia.org including all above details.

You can view and copy the source of this page:

((short description|Miniature high-gain dual triode vacuum tube))
((Infobox vacuum tube
  |image          = 12AX7 tube.jpg
  |caption        = 12AX7
  |classification = Dual triode
  |service        = [[Class-A amplifier]]
  |height_in      = 2.2
  |diameter_in    = 0.8
  |weight_lbs     =
<!--Cathode-->
  |cathode_type     = Indirectly heated
  |heater_voltage   = 12.6 V (series)<br />6.3 V (parallel)
  |heater_current   = 150 mA (series)<br />300 mA (parallel)
  |filament_voltage =
  |filament_current =
<!--Anode-->
  |max_dissipation = 1 per section
  |max_voltage     = 300 V
<!--Socket connections (bottom view)-->
  |pinout = [[File:EIA-9A.png]]
<!--Class A amplifier ops-->
  |class_a_amplification_factor = 100
  |class_a_anode_voltage        = 250 V
  |class_a_anode_current        = 1.2 mA
  |lass_a_screen_voltage        =
  |class_a_bias_voltage         = −2 V
  |class_a_anode_resistance = 62.5 kΩ
<!--Class C amplifier ops-->
  <!--Highest rated CCS specification (recommended)-->
  |class_c_power_output   =
  |class_c_anode_voltage  =
  |class_c_anode_current  =
  |class_c_screen_voltage =
  |class_c_bias_voltage   =
<!-- Class AB amplifier ops -->
  <!--Highest rated CCS specification (recommended)-->
  |class_ab_power_output     =
  |class_ab_anode_resistance =
  |class_ab_anode_voltage    =
  |class_ab_anode_current    =
  |class_ab_screen_voltage   =
  |class_ab_bias_voltage     =
  |reference = [https://drtube.com/datasheets/12ax7-sylvania1955.pdf Sylvania 12AX7 datasheet]
))
'''12AX7''' (also known as ECC83<ref>((cite web |url=http://www.thetubestore.com/Tubes/12AX7-ECC83-Tube-Types |title = www.thetubestore.com - 12AX7 / ECC83 Tube Types))</ref>) is a miniature dual-[[triode]] [[6AV6]] [[vacuum tube]] with high voltage [[gain (electronics)|gain]]. Developed around 1946 by [[RCA]] engineers<ref name="vintage">((cite journal|last=Jung|first=David|title=Draw! A 12AX7 'Shootout'|journal=[[Vintage Guitar (magazine)|Vintage Guitar]]|date=September 2010|pages=114 ))</ref> in [[Camden, New Jersey]], under developmental number A-4522, it was released for public sale under the 12AX7 identifier on September 15, 1947.

The 12AX7 was originally intended as replacement for the [[6SL7]] family of dual-triode amplifier tubes for audio applications.  As a popular choice for guitar tube amplifiers, its ongoing use in such equipment makes it one of the few small-signal vacuum tubes in continuous production since it was introduced.

==History==
The 12AX7 is a twin triode basically composed of two of the triodes from a 6AV6, a double diode triode.  The 6AV6 is a miniature repackaging (with just a single cathode) of the triode and twin diodes from the octal [[6SQ7]] (a double-diode triode used in AM radios), which itself is very similar to the older type 75 triode-diode dating from 1930.

==Application==
((more citations needed section|date=March 2022))
[[File:TriodeECC83Characteristic1.png|thumb|Anode current characteristic with grid voltage as parameter]]
The 12AX7 is a high-gain (typical amplification factor 100), low-plate-current [[triode]] best suited for low-level audio voltage amplification.  In this role it is widely used for the preamplifier (input and mid-level) stages of audio amplifiers. It has relatively high [[Miller effect|Miller]] capacitance, making it unsuitable for radio-frequency use.

Typically a 12AX7 triode is configured with a high-value plate resistor, 100 kohms in most guitar amps and 220 kΩ or more in high-fidelity equipment. Grid bias is most often provided by a cathode resistor.  If the cathode resistor is unbypassed, negative feedback is introduced and each half of a 12AX7 provides a typical voltage gain of about 30; the amplification factor is basically twice the maximum stage gain, as the plate impedance must be matched.  Thus half the voltage is across the tube at rest, half across the load resistor. The cathode resistor can be bypassed to reduce or eliminate AC negative feedback and thereby increase gain; maximum gain is about 60 times with a 100k plate load, and a center biased and bypassed cathode, and higher with a larger plate load.<ref>((cite web |url=https://www.ampbooks.com/mobile/amplifier-calculators/output-impedance/calculator/ |title = Preamp Gain and Output Impedance Calculator))</ref>

<math>A_v = \mu \times R_{tot} /(r_P + R_{tot} + (R_K \times (\mu + 1))</math>

Where <math>A_v</math> = voltage gain, <math>\mu</math> is the amplification factor of the valve, <math>r_P</math> is the internal plate resistance, <math>R_K</math> is the cathode resistor and <math>R_{tot}</math> is the parallel combination of <math>R_P</math> (external plate resistor) and <math>R_{load}</math>. If the cathode resistor is bypassed, use <math>R_K = 0</math>.

The initial “12” in the designator implies a 12-volt heater requirement; however, the tube has a center-tapped heater so it can be used in either 6.3-V or 12.6-V heater circuits.

==Similar twin-triode designs==
The 12AX7 is the most common member of what eventually became a large family of twin-triode vacuum tubes, manufactured all over the world, all sharing the same pinout (EIA 9A). Most use heaters which can be optionally wired in series (12.6V, 150&nbsp;mA) or parallel (6.3V, 300&nbsp;mA).  Other tubes, which in some cases can be used interchangeably in an emergency or for different performance characteristics, include the [[12AT7]], [[12AU7]], [[12AV7]], 12AY7, and the low-voltage 12U7, plus many four-digit EIA series dual triodes.  They span a wide range of voltage gain and transconductance. Different versions of each were designed for enhanced ruggedness, low [[microphonics]], stability, lifespan, etc.

Those other designs offer lower voltage gain (traded off for higher plate current) than the 12AX7 (which has a voltage gain or <math>A_v</math> of 100), and are more suitable for high-frequency applications.

Some American designs similar to the 12AX7:

* 12AD7 (October 10, 1955 - 225mA heater - low hum)
* [[12AT7]]<ref>killerrig.com,((cite web |url=https://killerrig.com/12ax7-vs-12at7/ |title = 12AX7 vs 12AT7 Tube Types| date=13 April 2022 ))</ref> (May 20, 1947, dual 6AB4, <math>A_v</math> = 60)
* [[12AU7]] (October 18, 1946, dual 6C4,<ref>((Cite web|url=https://www.thetubestore.com/preamp-tubes/6c4-m8080-tube-types|title=www.thetubestore.com - Tubes with part numbers beginning with 6C4 - M8080 Tube|website=www.thetubestore.com))</ref> <math>A_v</math> = 17-20)
* 12AV7 (February 14, 1950 - dual 6BC4, <math>A_v</math> = 37-41)
* '''12AX7''' (September 15, 1947 - dual 6DR4, also like octal 6SL7, <math>A_v</math> = 100) dual 12AV6 (6AV6)
* 12AY7 (December 7, 1948 - <math>A_v</math> = 44, for audio preamp use)<ref>((Cite web|url=https://www.thetubestore.com/preamp-tubes/12ay7-6072-tube-types|title=www.thetubestore.com - Tubes with part numbers beginning with 12AY7 - 6072 Tube|website=www.thetubestore.com))</ref>
* 12AZ7 (March 2, 1951 - 225mA heater, <math>A_v</math> = 60)
* 12DF7 (<math>A_v</math> = 100, low microphonics)
* 12DT7 (<math>A_v</math> = 100)
* 12DW7 <ref>((Cite web|url=https://www.thetubestore.com/preamp-tubes/12dw7-7247-tube-types|title=www.thetubestore.com - Tubes with part numbers beginning with 12DW7 - 7247 Tube|website=www.thetubestore.com))</ref>(First triode: <math>A_v</math> = 100, Second triode: <math>A_v</math> = 17)
* 12U7  (<math>A_v</math> = 20, for use in automotive radios on 12-volt plate supply)

Although commonly known in Europe by its [[Mullard–Philips tube designation]] of ECC83, other European variations also exist including the low-[[signal noise|noise]] versions 12AX7A, 12AD7, 6681, 7025, and 7729; European versions B339, B759, CV492, CV4004, CV8156, CV8222, ECC803, ECC803S, E2164, and M8137; and the lower-gain low-noise versions 5751 and 6851, intended for avionics equipment.

In European usage special-quality valves of some sort were often indicated by exchanging letters and digits in the name: the E83CC was a special-quality ECC83.
In the US a "W" in the designation, as in 12AX7WA, designates the tube as complying with military grade, higher reliability specifications.

The 'E' in the European designation classifies this as having a 6.3 volt heater, whereas the American designation of 12AX7 classifies it as having a 12.6 volt heater.  It can, of course, be wired for operation off either voltage.

==Manufacturers==
((As of|2022)) versions of the 12AX7/ECC83 are available from the following manufacturers:
* In [[Russia]]:  [[Sovtek|New Sensor]], which produces tubes under the [[Sovtek]], [[Electro-Harmonix]], Svetlana, [[Tung-Sol]], and [[Mullard]] brands
* In [[Slovakia]]:  [[JJ Electronic]] (annual production of approximately two million units)
* In [[China]]:  [[Changsha Hengyang Electronics(Company)|Hengyang Electronics]], Tubes<ref>Classic series ECC83,((cite web |url=http://www.psvane.com/hifixl/714.html |title = Changsha Hengyang Electronics Co., Ltd.))</ref> sold under Psvane and TAD<ref>Sales network,((cite web |url=http://www.psvane.com/en/salesnetwork.html |title = Changsha Hengyang Electronics Co., Ltd.))</ref> brand names. Company owns its independent manufacturing facility in Southern China<ref>Rachel Zhang,((cite web|url=https://premiumvacuumtubes.com/who-is-psvane/ |title = Who is Psvane?))</ref> (former Guiguang tube factory)<ref>Rachel Zhang,((cite web |url=https://premiumvacuumtubes.com/who-was-guiguang/ |title = Who was GuiGuang))</ref> and recently they acquired former small signal tube manufacturing line from Tianjin Quanzheng factory (TJ Full Music) <ref>About Linlai Team,((cite web |url=https://www.linlaiglobal.com/ |title = LINLAI Global))((cite web |url=http://www.linlaitube.com/en/ |title = Changsha Qiangsheng Light Power Co., Ltd.))</ref>

==Gallery==
<gallery>
  File:Electro-harmonix 12AX7EH.JPG|Electro-Harmonix 12AX7EH
  File:ECC83 var.jpg|Various brands of 12AX7, with measuring tape to indicate size
  File:Dubulttriode darbiibaa.jpg|Tungsram ECC83 during operation
  File:Philips 12AX7WA tube.jpg|Philips JAN 12AX7WA (Joint Army Navy)
</gallery>

==See also==
* [[List of vacuum tubes]]

==References==
((reflist))

==External links==
* [http://tdsl.duncanamps.com/show.php?des=12AX7 Duncan's Amps TDSL.]
* [https://web.archive.org/web/20180412193231/http://tubedata.milbert.com/sheets11.html Several tube datasheets.]
* [http://www.tubemaze.info/tag/12ax7/ Reviews of 12ax7 tubes.]
* [https://web.archive.org/web/20180430094424/http://www.effectrode.com/signal-tubes/12ax7-tube-cornerstone-guitar-tone/ The 12AX7 tube.]
* [https://www.jj-electronic.com/ecc83s-12ax7-7025 12AX7/ECC83 page] (with [https://www.jj-electronic.com/images/stories/product/preamplifying_tubes/pdf/ecc83s.pdf datasheet]) at [https://www.jj-electronic.com/ JJ Electronic]

((DEFAULTSORT:12ax7))
[[Category:Vacuum tubes]]
[[Category:Guitar amplification tubes]]
[[Category:RCA]]

Pages transcluded onto the current version of this page (help):

12AX7 (edit)
Template:Ambox (view source) (template editor protected)
Template:As of (view source) (template editor protected)
Template:Cite journal (view source) (protected)
Template:Cite web (view source) (protected)
Template:Convert (view source) (template editor protected)
Template:DMCA (view source) (template editor protected)
Template:Dated maintenance category (view source) (template editor protected)
Template:Dated maintenance category (articles) (view source) (template editor protected)
Template:FULLROOTPAGENAME (view source) (template editor protected)
Template:Infobox (view source) (template editor protected)
Template:Infobox vacuum tube (edit)
Template:Main other (view source) (protected)
Template:More citations needed (view source) (template editor protected)
Template:More citations needed section (view source) (template editor protected)
Template:Ns has subpages (view source) (protected)
Template:PAGENAMEBASE (view source) (template editor protected)
Template:Pagetype (view source) (protected)
Template:Reflist (view source) (protected)
Template:Reflist/styles.css (view source) (protected)
Template:SDcat (view source) (protected)
Template:Short description (view source) (protected)
Template:Short description/lowercasecheck (view source) (protected)
Template:Sp (view source) (template editor protected)
Template:Template other (view source) (protected)
Template:Yesno (view source) (protected)
Module:Arguments (view source) (protected)
Module:Category handler (view source) (protected)
Module:Category handler/blacklist (view source) (protected)
Module:Category handler/config (view source) (protected)
Module:Category handler/data (view source) (protected)
Module:Category handler/shared (view source) (protected)
Module:Check for unknown parameters (view source) (protected)
Module:Citation/CS1 (view source) (protected)
Module:Citation/CS1/COinS (view source) (protected)
Module:Citation/CS1/Configuration (view source) (protected)
Module:Citation/CS1/Date validation (view source) (protected)
Module:Citation/CS1/Identifiers (view source) (protected)
Module:Citation/CS1/Utilities (view source) (protected)
Module:Citation/CS1/Whitelist (view source) (protected)
Module:Citation/CS1/styles.css (view source) (protected)
Module:Convert (view source) (template editor protected)
Module:Convert/data (view source) (template editor protected)
Module:Convert/text (view source) (template editor protected)
Module:Disambiguation/templates (view source) (protected)
Module:Infobox (view source) (template editor protected)
Module:Infobox/styles.css (view source) (template editor protected)
Module:InfoboxImage (view source) (template editor protected)
Module:Message box (view source) (protected)
Module:Message box/ambox.css (view source) (protected)
Module:Message box/configuration (view source) (protected)
Module:Namespace detect/config (view source) (protected)
Module:Namespace detect/data (view source) (protected)
Module:Ns has subpages (view source) (protected)
Module:Pagetype (view source) (protected)
Module:Pagetype/config (view source) (protected)
Module:Pagetype/disambiguation (view source) (protected)
Module:Pagetype/setindex (view source) (protected)
Module:Pagetype/softredirect (view source) (protected)
Module:SDcat (view source) (protected)
Module:String (view source) (protected)
Module:Unsubst (view source) (protected)
Module:Wikitext Parsing (view source) (protected)
Module:Yesno (view source) (protected)

Return to 12AX7.

Retrieved from "https://en.wikipedia.org/wiki/12AX7"