(!!!!) (Best Overall Single) 5691 RCA red base branded Sylvania black plates NOS 1950's (2.6/2.6ma) 1% section balance
(!!!!) (Best Pair 1965) 5691 RCA Red Base Black Plates NOS branded GE 1965 (2.5/2.5ma and 2.3/2.5ma) (Same Gm for both tubes)
(!!!!) (Best Pair) 5691 RCA red base branded Sylvania and GE black plates NOS 1960-1965 (2.3/2.3ma and 2.2/2.4ma) 1-2% matched
(!!!!) (Best Single) 5691 RCA Red Base branded GE Black Plates NOS 1957 (2.4/2.6ma)
(!!!!) (Recommended Pair) 5691 RCA Red Base Black Plates rebranded GE NOS 1965 (2.1/2.6ma and 2.2/2.7ma)
(!!!!) (Recommended Single) 5691 RCA Red Base Black Plates NOS 1953 (2.0ma/2.2ma)
(!!!!) (Recommended Single) 5691 RCA red base branded Sylvania black plates NOS 1950's (2.0/2.0ma) 1% section balance
(!!!) (Best Single) 5691 RCA Red Base Black Plates rebranded GE NOS 1965 (2.2/2.2ma) 1% section balance
(!!) (BEST VALUE) 5691 RCA Red Base gray plates low hours/tests like new 1966 - broken center guide pin (2.5/2.6ma) 1-2% section balance
