6B4G Tungsol coated glass NOS 1940”s

81ma

Gm=6100

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)