(!!!) (Best Pair #3) 448A Western Electric tipped top used/good 1965-1966 (28ma and 29.2ma) (same Gm)

1 pair) 448A Western Electric “”tipped top”” used/good “”D”” getter halo in white boxes

1 tube) 28.0ma Gm=26,000 (6613=1966)

1 tube) 29.2ma Gm=26,000 (6526=1965)

Amplitrex Test Data:

Vplate=135V

Vscreen=135V

Vgrid=-2.5V

Good Ma range 18-25ma

Good Gm = 25,000

DIY pentode