The 6BC7 is an American designed miniature, dual-triode vacuum tube from the 1950s. It is a small, glass cylindrical tube typically measuring 2.75 inches in length and 0.5 inch in diameter, with a base containing 5 pins. It is capable of high-mu amplification and moderate power gain. It was used in pre-amplifier circuits, including phono pre-amps, guitar amplifiers, and radio and TV receivers. It is also used in some logic circuits and other applications where extremely low noise levels and a long life need to be maintained.