(!!) (Good Value Pair) CX-71A and 71A RCA/Cunningham Balloon used/good 1930 era (21ma and 18.5ma) (same Gm)

1 pair) UX-CX-71A and 71A RCA/Cunningham Balloon used/good 1930 era in white boxes

1 tube) 21.0mA Gm=1700 (71A RCA)

1 tube) 18.5mA Gm=1700 (CX-71A Cunningham)

(71A=5V @ .25A Filament)
(Typical Characteristics:Vplate=135V, Vgrid=-27, Iplate=17.5ma, Rplate=1.82Kohms
Gm=1650, Mu=3, Rload=3Kohms, Pout=0.4watts)