JANCHS 6SL7GT VT-229

Premium military-grade contract version of the octal 8-pin high-mu twin triode manufactured by Hytron under strict military requirements for long-term electrical matching and mechanical ruggedness. Equivalents: 6SL7, 6SL7GT, VT-229, 5691, 6N9S. Real-Life Examples: US Army Air Forces aircraft communication setups, vintage Ampeg B-15 Portaflex bass amplifiers, early McIntosh high-fidelity monoblocks.