(!!!!) (Best Pair #1) 448A Western Electric tipped top used/test like new 1965 (27.2ma and 27.3ma) 1-2% matched

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

1 tube) 27.2ma Gm=26,400 (6552=1965)

1 tube) 27.3ma Gm=26,600 (6539=1965)

Amplitrex Test Data:

Vplate=135V

Vscreen=135V

Vgrid=-2.5V

Good Ma range 18-25ma

Good Gm = 25,000

DIY pentode