6DR7 Raytheon black plates NOS around 1960 (1.2ma/40ma)

1 tube) 6DR7 Raytheon black plates NOS around 1960

1.2ma Gm=1400

40ma Gm=6900

Good Triode = 1.0-1.5ma Gm=1400-1600

Good Pentode = 25-35ma Gm=5500-6000

– Border Patrol