EL84 Power Valve for Guitar Amplifier (Alt 6BQ5)


The EL84 Power Valve for Guitar Amplifier (Alternative 6BQ5) is a power pentode vacuum tube developed by Philips in 1953 for use in the British Mullard 5/10 amplifier. It has a 9 pin Noval base and is used mainly in the power output stages of audio amplifier circuits. It is most commonly found now in valve guitar amplifiers however it was originally developed for radios and other audio devices. The EL84 valve is used in the power stage of valve guitar amplifiers in either matched pairs or quads. These are specially selected valves with similar characteristics to ensure the amplifier works correctly. The EL84 Power Valve for Guitar Amplifier is smaller and more sensitive than the 6V6 valve  that was widely used around the world until the 1960s. You can buy the EL84 Power Valve for Guitar Amplifier below however it is mot likely you will need to buy a EL84 matched pair or EL84 matched quad. Use the links at the bottom of the page to find your valve or amplifier. Also, read our Guide to Replacing Guitar Amplifier Valves.

Buy the EL84 Power Valve for Guitar Amplifier (Alt 6BQ5)

Tested and Matched EL84 Valves

More about the EL84 Power Valve for Guitar Amplifier (Alt 6BQ5)

History, the EL84 was developed to eliminate the need for a driver tube in radio designs producing full output from a relatively small drive signal. This eliminated the need for a preamplifier valve in radios, making them cheaper to produce. The EL84 (6BQ5) Power Valve for Guitar Amplifier was also cheap to produce and manufacturers were quick to adopt it in new designs. A single EL84 was used in low-cost equipment, and a push-pull pair of two valves were used for lower distortion and higher power. In common with all ‘E’ prefix tubes, using the Mullard-Philips tube designation, it has a heater voltage of 6.3V.

  • The EL84 requires less than 4.4Vrms for 5.7W output
  • The 6V6 requires 9.0Vrms for 5.5W output
  • The EL34 requires 8.7Vrms for 11W output.

Use in early guitar amplifier design. The EL84, when used at its rated plate voltage of 300VDC in a Class AB1 push-pull configuration can produce 17w output. Many guitar amplifiers run EL84 tubes in excess of 400VDC with 2 EL84’s in a push pull configuration and a plate voltage of around 420VDC giving 25w output. The EL84 came to prominence when used in Watkins (and later the Vox) amplifiers preferred by many British invasion bands of the 1960s.[citation needed] When overdriven, the EL84 power tubes in these amplifiers produce a distinctive chiming, articulate, treble-heavy sound when compared to 6L6 tubes more commonly used in American amplifiers of the era such as those from Fender.

Alternative Valves to the EL84

Other interchangeable valves developed by other manufacturers around the world that have the same design as the EL84 (6BQ5) Power Valve for Guitar Amplifier are:

  • 6BQ5 – as used in the North American market. Some manufacturers label their versions of the EL84 as “EL84/6BQ5” or “6BQ5/EL84” or simply “6BQ5”
  • N709 – as sold by General Electric Co. Ltd. of England
  • Other equivalent tubes are the 7189, 7189A and CV2975.
  • The E84L is a long life, 10000 hours, professional version with the 6P14P as a direct equivalent.
  • The 6P14-EV or EL84M is an extended rating, Russian Milatary, version popular with Guitar players due to low noise and durability.

Manufacturers – The EL84 and alternatives are manufactured in Russia (Sovtek and Electro-Harmonix brands), Slovakia (JJ Electronic), and Serbia (Ei). The Sovtek EL84 is often sold under their own brand name by other well-known electric guitar and guitar amplifier manufacturers – such as Fender or Mesa Boogie. Popular guitar amplifier makes which use the EL84 valve in their guitar amplifiers includes Mesa Boogie, Fender, Laney, Vox, Marshall, Peavey, Orange and Carlsbro.

More Guitar Amplifier Links

  • Buy Guitar Amp Valves Matched Sets
    • Matched sets of pre-amplifier and power output valves to ensure the maximum performance from your amplifier.
  • Buy Full Guitar Amp Re-Valve Kits
    • The best way to get the best from you guitar amplifier. By changing all of the valves as a complete set maximum performance from the amplifier can be assured. Changing individual valves can be a false economy as the one weak link in the chain will affect the overall performance.
  • Look Up Your Guitar Amplifier
    • We have kits available for most guitar amplifiers. Use the link above or the SEARCH feature to look up your amplifier.

Is your Guitar Amplifier not performing like it did when new? 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 and matched sets available for the most popular amplifier types – see the links above.