(!!!!!) (Best Overall Pair) 311B Western Electric NOS 1972-1974 (32ma and 33.4ma)

1 pair) 311B Western Electric NOS 1972-1974 original boxes

1 tube) 32.0ma and Gm=3060 (1972)

1 tube) 33.4ma and Gm=3100 (1974)

Tested on Amplitrex

Vplate=180V

Vscreen=135V

Vgrid=-15V

Good Ma = 30ma

Good Gm = 2900