1 matched pair) 6B4G Raytheon NOS 1940”s separate plates

1 tube) 90.0ma Gm=5850 Raytheon branded Philco same build

1 tube) 91.5ma Gm=5600 Raytheon – hairline crack in base – see pic

Test Data:

Vplate=225V

Vgrid=-30V

GOOD NOS Ma range 70-90ma

GOOD NOS Gm = 5200

Recommended for

(6B4G=6.3V filament)
(6B4G is electrically equivalent to 6A3, but 6A3 has UX-4 pin base and 6B4G has 8 pin octal base)
(The best sounding 6B4G are 1940”s-1950”s: Ken Rad, Tungsol, Sylvania, Raytheon)