(!!!!) (Best Pair #2) 6F6G Marconi Spain NOS 1940's (37.5ma and 39ma)

1 matched pair) 6F6G Marconi Spain NOS 1940's 1 tube) 37.5ma Gm=2850 slight rattle inside base - slightly taller bottle 1 tube) 39.0ma Gm=2770   Test settings: Vplate=285V Vscreen=285V Vgrid=-20V Good Ma range = 32-38ma Good Gm range = 2400-2600   Recommended for - Sparton Nocturne 1186 from 1936- Fire Stone Sir Chef S-7404-3 1939- Montgomery-Ward Airline Model 62-226- Supratek Cortese- Victoria- WE 106 preamp clone - Wards Airline Radio