(!!!!) (Best Pair #1) 6F8G Raytheon black parallel ribbed plates NOS 1940”s (8.8/7.8ma and 7.4/7.6ma) (same Gm)

1 pair) 6F8G Raytheon black parallel ribbed plates NOS 1940”s

1 tube) 8.8/7.8ma Gm=2800/2700

1 tube) 7.4/7.6ma Gm=2700/2800

Good Ma range 7-9ma

Good Gm range 2400-2600

NOTES:

GE, Sylvania and Raytheon have mirror image parallel black plates

RCA and Ken Rad have staggered black ribbed plates

6F8G dual triode = (2) 6J5G”s triodes in 1 tube