12AX7 (ECC83) Guitar Amplifier Valves (Amp Tubes)

Tungsol 12AX7 Amplifier Valve

The 12AX7 (ECC83) guitar amplifier tube, also known in Europe as the ECC83 valve, was created in 1946 as a miniature dual triode 6AV6 valve with high voltage gain. The replacement 12ax7 tube was developed by RCA engineers in the USA. It was then released for public sale with the 12AX7 tube identifier number on September 15, 1947. 12AX7 tubes were designed as a replacement for 6SL7 valves that were commonly used in audio systems in the 40s. The 12AX7 tube is very popular with valve guitar amplifier designers and this has kept the 12AX7 valve it in continuous production since 1947. The 12AX7 tube, as it is known in the US, or the European ECC83 valve is mainly used in the pre-amplifier section of valve guitar amplifier circuits. This is due to the high gain characteristic of 12AX7 tubes when compared to other similar pre-amp valves.

To get an in-depth look at how replacement 12ax7 tubes can affect the tone of your tube guitar amp read our guide to pre-amplifier valves page. We have discussed how the various replacement 12ax7 and similar sized valves have different gain levels and how these can shape your tube amp tone.

The Yumagold website includes many different replacement guitar amp valves for all the popular guitar amplifier brands and tube amp models, old and new. Buying replacement guitar amplifier valves is easy, just look up your tube guitar amplifier model using the links below or the search icon in the top menu. The replacement 12ax7 tubes can be purchased as single valves, matched valve pairs, matched valve quads, full amplifier matched sets and complete amplifier valve kits.

Buy the 12AX7 (ECC83) Guitar Amplifier Valve (Tube)

Use the links on this page to find the replacement tubes for your valve guitar amp. You can buy the 12AX7 (ECC83) valve below using the links. The 12AX7 valve is one of many guitar amplifier pre-amp valves that are available on the site. Use the links below to buy the 12AX7 guitar amp valve, ECC83 is the European alternative code.

Buy 12AX7 Tested Valve Sets

Use the website links to buy replacement 12ax7 tubes, or replacement 12ax7 tubes, for your tube guitar amp model. Popular sets of 12AX7 tubes, or ECC83 valves, are listed below.

About the 12AX7 (ECC83) Guitar Amplifier Valve (Tube)

The 12AX7 (ECC83) Valve for Guitar Amplifier is more commonly known in Europe by its Mullard-Philips tube designation of ECC83 however there are also many other alternative types developed for specific equipment and for military use.It is estimated that over 2 million 12ax7 tubes are produced annually. These are mainly used in new amplifier production and the replacement market. As of 2012 the 12AX7 (ECC83) Valve for Guitar Amplifier was being manufactured in various styles and brands by the following main manufacturers: JJ Electronic, Winged C, New Sensor, Shuguang.

  • Application – The 12AX7 (ECC83) Valve for Guitar Amplifier is a high-gain, 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. The 12AX7 tube has relatively high Miller capacitance, making it unsuitable for radio-frequency use. The initial “12” in the designation implies a 12-volt heater requirement; however, the tube has a center-tapped heater so it can be used in either 6.3V or 12.6V heater circuits. The 12AX7 tube is the most commonly used in tube guitar amplifier designs. It can be found in the pre-amplifier stages of most classic, b guitar amplifiers.
  • Alternative – A common alternative used by some guitarists is to is to replace the first high gain 12AX7 pre-amplifier valve in the guitar amplifier input circuit with a 5751 low gain valve.
  • The SRV 5751 swap – This will lower the overall gain of a preamp stage. You can swap a 5751 guitar amp valve into any socket that carries a 12AX7 valve. To lower the gain even more but retain the same performance characteristics (other than gain) you can use a 12AY7 pre-amp valve.  This 5751 swap is a trick that was used by Stevie Ray Vaughan, for one, to help generate his signature tone, and it has also been employed by plenty of other great blues players.

Other Valve Products to Consider

Is your Guitar Amplifier Struggling? Has the output sound begun to degrade and break up? Are you experiencing additional noise and distortion? If yes, then it is time to consider replacing some or all of the valves in your guitar amplifier. Guitar amplifier valves (or tubes as they are known in the USA) are robust and will work for many hours. Performance will be affected by mistreating them or allowing them to overheat. Generally the performance of vacuum tubes starts to degrades with the amount of time they are used and up to 1000 hours is typically the optimum life of a valve or tube. If the performance of your amplifier is failing then it is likely that some or all of the valves need replacement.

When replacing guitar amplifier valves it is best to use matched pairs as this will ensure the valves last as long as possible with the best sound quality. We have a full range of replacement guitar amplifier valves , full tube sets and matched sets available for the most popular amplifier types – see the links above.