(!!!!!) (Best Overall Pair) 6C10 GE rebranded RCA NOS 1960's (Ampeg / Fender) (1.6ma/1.5ma/1.4ma) and (1.5ma/1.8ma/1.4ma)
(!!!!!) (Best Overall Pair) 6C10 GE rebranded RCA NOS 1960's (Ampeg / Fender) (1.6ma/1.6ma/1.3ma) and (1.6ma/1.3ma/1.7ma) (Best Pair in the World)
(!!!!!) (Best Overall Single) JAN-5691 Sylvania black plates NOS 1977 (2.8/3.1mA) (Same Gm) (Best 6SL7GT sub) (same internals as 5691 red base)
(!!!!!) (Best Pair) JAN-5691 Sylvania black plates NOS 1977 (2.1/2.2mA and 2.1/2.3mA) (Best 6SL7GT sub) (same internals as 5691 red base)
(!!!!!) (Best Pair) JAN-5691 Sylvania black plates NOS 1979 (2.0/2.1mA and 2.1/2.1mA) (Best 6SL7GT sub) (same internals as 5691 red base)
(!!!!!) (Best Value Single) JAN-5691 Philips by Sylvania black plates NOS 1985 (2.4/2.6ma) (Best 6SL7GT sub)
(!!!!!) (Recommended Pair) 6C10 GE rebranded RCA NOS 1960's (Ampeg / Fender) (1.0ma/1.2ma/1.2ma) and (1.0ma/1.1ma/1.3ma)
(!!!!!) (Recommended Pair) 6C10 GE rebranded Westinghouse NOS 1970 era (Ampeg / Fender) (1.3ma/1.4ma/1.2ma) and (1.3ma/1.2ma/1.1ma)
(!!!!!) (Recommended Single) JAN-5691 Sylvania black plates NOS 1979 (2.2/2.4mA (Best 6SL7GT sub) (same internals as 5691 red base)
(!!!!!) (RecommendedPair) JAN-5691 Philips by Sylvania black plates NOS 1984-1985 (2.0/2.2mA and 2.1/2.4mA) (Best 6SL7GT sub) (same internals as 5691 red base) 1-3% matched
(!!!!) (2nd Best RCA Single) 6C10 RCA branded Westinghouse NOS 1971 (Ampeg / Fender) (1.0ma/2.1ma/1.6ma) (Strongest Single)
(!!!!) (BEST PAIR) 7027A RCA NOS 1970 era same build (68.6ma and 69ma) 1-3% matched
(!!!!) (Best Single #1) 6C10 GE rebranded RCA NOS 1960's (Ampeg / Fender) (1.3ma/1.3ma/1.0ma)
(!!!!) (Best Single) 6C10 GE rebranded Westinghouse NOS 1970 era (Ampeg / Fender) (1.5ma/1.4ma/1.6ma)
(!!!!) (Best Single) 6C10 RCA branded Westinghouse NOS 1971 (Ampeg / Fender) (1.4ma/2.0ma/1.5ma) (Strongest Single)
(!!!!) (Recommended Pair) 7027A RCA NOS 1970 era same build (65.5ma and 66.5ma) 1-3% matched
(!!!!) (Recommended Pair) 7027A RCA tall bottle NOS 1960's (74ma and 79.2ma)
(!!!!) (Recommended Pair) JAN-5691 Sylvania black plates NOS 1979 (2.1/2.2mA and 2.0/2.2mA) 1-3% matched (Best 6SL7GT sub) (same internals as 5691 red base)
(!!!) (Best Pair) 7868 Sylvania NOS tipped top 1970 era (60ma and 63ma) (getting rare)
(!!!) (Best RCA Single) 7199 RCA Black Plates NOS 1966 (14/7.2ma)