6B4G Ken Rad branded RCA coated glass NOS 1946 in white box

110ma

Gm=6600

tube plugged into octal socket in photo

Test Data: Vplate=225V, Vgrid=-30V

(NOS Ma range 80-100ma)

(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)