6DR7 Sylvania branded GE black plates NOS 1977 (4.6ma/25ma)

1 tube) 6DR7 Sylvania branded GE black plates NOS 1977 (SL)

4.6ma Gm=3300

25ma Gm=5100

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

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

– Border Patrol