(!!) (1 Pair) 31 Cunningham NOS 1940”s (11ma and 11.6ma)

1 pair) 31 Cunningham NOS 1940”s

1 tube) 11.6ma and Gm=1000 gold printing

1 tube) 11.0ma and Gm=1000 silver printing

Tested on Amplitrex

Vplate=180V

Vgrid=-30V

Good NOS Ma = 11 -12ma

Good Gm = 1000