(!) (Recommended Pair) 76 Sylvania black plate branded Tungsol and Westinghouse NOS 1946 (5.6ma and 5.4ma)

1 pair) 76 Sylvania black plate branded Tungsol/Westinghouse NOS 1946 same build

1 tube) 5.6ma Gm=1300 Tungsol made in 1946 branded Tungsol in 1951

1 tube) 5.4ma Gm=1400 Westinghouse

Matched on Amplitrex

Vplate=250V

Vgrid=-13.5V

Good Ma range = 4.5 - 5ma

Good Gm range = 1300-1400