(!) Recommended Pair) 37 RCA branded GE NOS 1946 and RCA like new 1930”s (7.3ma and 8.3ma)

1 pair) 37 RCA branded GE NOS 1946 and RCA like new 1930”s

1 tube) 7.3ma Gm=1100 RCA branded GE NOS 1946 NOS

1 tube) 8.3ma Gm=1100 RCA Cunningham engraved abse 1930”s like new

Test parameters:

Vplate=250V

Vgrid=-18V

Iplate good range 6.5-8ma

Gm=1000-1100

(Filament=6.3V @ 300ma, many think the 37 sounds better than the 76)