6V6

The 6V6 is a beam-power tetrode vacuum tube. The first of this family of tubes to be introduced was the 6V6G by Ken-Rad Tube & Lamp Corporation in late 1936,^[1] with the availability by December of both Ken-Rad and Raytheon 6V6G tubes announced.^[2] It is still in use in audio applications, especially electric guitar amplifiers.^[3]

Following the introduction in July 1936 of the 6L6, the potential of the scaled down version that became the 6V6 was soon realized. The lower-powered 6V6 was better-suited for average home use, and became common in the audio-output-stages of "farmhouse" table-top radios, where power pentodes such as the 6F6 had previously been used. The 6V6 required less heater power and produced less distortion than the 6F6, while yielding higher output in both single-ended and push-pull configurations.

Although the 6V6 was originally designed especially for use in automobile radios,^[4] the clip-in Loctal base 7C5,^[5] from early 1939, or the lower heater current 12V6GT, both with the identical characteristics to the 6V6, but with the smaller T-9 glass envelope, soon became the tubes of choice for many automotive radios manufacturers. Additionally, the 6V6 had applications in portable battery-operated radios.^[6]

The data sheet information supplied by the tube manufacturers' design-centers list the typical operation of an audio output stage for a single 6V6 as producing about 5W of continuous power, and a push-pull-pair about 14W. Amplifier manufacturers soon realized that the tube was capable of being used at ratings above the recommended maximums, and guitar amplifiers with 400V on the plates of a pair of 6V6GTA claim to produce an output power of 20W RMS at 5%THD with 40W Peak Music Power, and with 490V on the plates, as much as 30 W RMS.