(!) (Good Value Pair) 6S4A RCA USA black plate NOS 1960”s – 1970”s (19ma and 18.8ma)

1 pair) 6S4A RCA black plate NOS

1 tube) 19ma Gm=3900 (“”O”” getter 1970”s

1 tube) 18.8ma Gm=3800 (“”U”” getter 1960”s) on left

Good mA = 20+

Good Gm = 4000+

(the 6S4A features high plate current at relatively low plate voltages and is capable
of withstanding high pulse voltages)(Vfil=6.3V @ 600ma)
MAX Ratings: Vplate=550V, Iplate=30ma, Pout=8.5 watts
Typical Operation: Vplate=250V, Vgrid=-8V, Iplate=24ma, Mu=16.5, Gm=4500, Rplate=3700 ohms)

– Woo Audio GES Electrostatic headphone amp