6F5 Sylvania metal can NOS 1954 (1.0ma Gm=1500)

6F5 Sylvania metal can NOS 1954 (1.0ma Gm=1500)

NOS mA = 0.8-1.0mA+

NOS Gm = 1500+

(6F5 octal base is similar spec-wise to 7B4 loktal, Mu=100)

Zenith 10S669 radio 1941
Zenith 9S369 radio