The 6V6 is a beam-power tetrode, introduced by Radio Corporation of America RCA United States in mid 1937, and still in use in audio applications, especially electric guitar amplifiers. Similar to its predecessor, the 6L6, the 6V6 was far more widely used. 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. In an audio output stage, a single 6V6 can be used to produce about 5W (continuous) power, and a push-pull pair about 14W, with the higher output requiring a larger, more expensive output transformer with grain-oriented core laminations for better efficiency. The 6V6 became very popular for use in consumer-market musical instrument amplifiers, particularly combo-style guitar amps such as the Fender Champ, the Gibson GA-40, and the Fender Princeton Reverb, and Fender Deluxe Reverb amps, which run a push-pull pair of 6V6s at 410V-plus on the plates. Telefunken is prepared to add to this legacy by producing the best 6V6 made today. They are cryo treated, burnt in, and precisely matched to make sure they are the best option for all 6V6 applications. Please Note: Telefunken Black Diamond tubes are sold singly. Power tubes will be supplied in matched pairs or quads. Just order the quantity you need. If you want preamp tubes to be high gain or matched, just ask during checkout and we'll get it taken care of for you.