The 6L6 ( Russian type designation 6П3C ) is an electron tube which is designed as Strahlpentode or beam -power tetrode. It was developed in 1936 as a steel tube with a standard octal by Radio Corporation of America (RCA).

The Dutch company Philips was at that time owned a patent on pentode. To circumvent the patent licenses developed English tube engineers as early as 1933, the Strahlbündeltetrode and later sold the development of the American electronics manufacturer RCA. While this tube also has five electrodes in the electrode system, the function of which also corresponds in principle in a pentode, but it was referred to bypass the Pentodenpatents by the manufacturer as a tetrode.

In the beam -power tetrode the pentodentypische suppressor grid is replaced by specially shaped Elektronenleitbleche that focus the electrons flow from the cathode to the anode and through a space charge effect a similar effect on unwanted emission of secondary electrons from the anode unfold like the usual suppressor grid of a pentode.


The 6L6 is nowadays mainly used in the construction of tube amplifiers for electric guitars. It comes in the final stage are used. The "classic" 6L6 amplifiers are models of the Fender company, such as the "Fender Bassman " or " Fender Twin Reverb." Also, the sound of different amplifier models from Mesa / Boogie is based on these tubes, such as the "Mark IV", while others established amplifier manufacturer for the " sound " of their models to other types of tubes in the power stage set ( Marshall EL34 Vox: EL84 ).