The 6S8GT is an 8-pin octal combination vacuum tube engineered for detector and preamplifier service in AM/FM radio receivers and television audio stages. It integrates three independent signal diodes and a high-mu triode section inside a single glass envelope. Two of the diodes function as a balanced discriminator or ratio detector for FM demodulation, while the third diode handles AM detection and Automatic Volume Control (AVC). The high-mu triode section provides voltage preamplification for the audio signal. It operates on a 6.3V heater and fits standard 8-pin octal sockets. Available NOS and tested used.