This offer is only valid for the middle VALVO tube
1 x unused ECC86 tube
Valvo tube Hamburg Germany plant
Very good test result
S/gm = 4,2 + 4,5mA/V (100% = 4,6mA/V - usable starts with 2,8mA/V)
Final assessment: Only the slope/gm S/gm provides information about the emission
Further explanation: According to military standards, tubes with 60% (minimum value) were classified as usable.