(!!!!) (Best Overall Pair) JAN-5755 Raytheon Black Plates NOS 1973-1979 (1.9/2.0ma and 1.9/1.9ma) (Highest mA and Gm) 1-2% matched

1 pair) JAN-5755 Raytheon Black Plates NOS most 1973-1979

1 tube) 1.9/2.0ma Gm=1500/1600 (1979)

1 tube) 1.9/1.9ma Gm=1500/1600 (1973)

Good Ma 1.5-2.0ma

Good Gm = 1400-1500

Matched on Amplitrex

also see 420A/5755 Western Electric