(!!!!) (Recommended Pair) 311B Western Electric NOS 1973 and 1975 (35.2ma and 36.4ma) - Tube World Express
US$188.88
Product Details
1 pair) 311B WE NOS "O" getter halos in white boxes
1 tube) 36.4ma and Gm=3250 (1973)
1 tube) 35.2ma and Gm=3150 (1975)
Tested on Amplitrex
Vplate=180V
Vscreen=135V
Vgrid=-15V
Good Ma = 30ma
Good Gm = 2900