(!!!!!) (Best Overall Pair) 311B Western Electric NOS 1972-1974 (36.2ma and 37.8ma)

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

1 tube) 36.2ma and Gm=3200 (1972)

1 tube) 37.8ma and Gm=3060 (1974)

Tested on Amplitrex

Vplate=180V

Vscreen=135V

Vgrid=-15V

Good Ma = 30ma

Good Gm = 2900