(!!!) (2nd Best Pair) 311B Amperex made in Russia NOS 1977 (31.8ma and 33.2ma) (very good construction)

1 pair) 311B Amperex made in Russia NOS 1977 large getters – excellent conditon

1 tube) 31.8ma Gm=2850

1 tube) 33.2ma Gm=2900

Tested on Amplitrex

Vplate=180V

Vscreen=135V

Vgrid=-15V

Good Ma = 30ma

Good Gm = 2800-2900