(!!!!) (Best 6922 Single) USN-CEP-6922 Amperex USA NOS 1964 pins #7-#8 gently cleaned of oxidation (18.5ma/20.2ma) (Best American Made 6922)
(!!!!) (Best 6X5GT Single) JAN-CEA-5852=6X5GT Bendix NOS 1953 (64/40 and 65/40) (Best Audio Grade 6X5GT)
(!!!!) (Best 6X5GT Single) JAN-CEA-5852=6X5GT Bendix NOS 1953 (64/40 and 66/40) (Best Audio Grade 6X5GT)
(!!!!) (Best Overall Pair) JAN-CEA-5852=6X5GT Bendix NOS 1953 (65-66/40 x 2 tubes) 1% matched (Best Audio Grade 6X5GT)
(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (50-52/40 and 50-53/40 x 2 tubes)
(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (51-53/40 and 51-54/40 x 2 tubes)
(!!!!) (Best Pair) 5R4GB GE black base NOS 1981 (51-54/40 and 52-55/40 x 2 tubes)
(!!!!) (Best RCA Single 1964) 6201=12AT7WA RCA black plates NOS 1964 (9.8/7.4ma) (best tone)
(!!!!) (Best Siemens Pair) 12AT7=ECC81 Siemens Halske Germany branded "SATOR" NOS 1964 (9.0/9.3ma and 9.2/10ma) (close Gm)
(!!!!) (Best Single) 12AX7WA Sylvania NOS 1970's (Gm=3000/3100 and 2.5/2.5ma)
(!!!!) (Best Value Pair) 12AX7 Telefunken Germany <> bottom ribbed plates used/very good 1960 era (1.0/1.2ma and 1.0/1.1ma) 1-5% matched
(!!!!) (Best Value Single) 12AX7 Telefunken Germany smooth plates branded DYNACO like new 1964 (Gm=1600/1800 and 0.9/1.4ma)
(!!!!) (Best Value Single) 6550 Tungsol branded Sylvania smooth gray plate used/tests like new 1960 era (138ma)
(!!!!) (Best Value Single) JAN-CEA-5852=6X5GT Bendix NOS 1953 (63/40 and 66/40) (Best Audio Grade 6X5GT)
(!!!!) (Best Value Single) JAN-CEA-5852=6X5GT Bendix NOS 1953 imperfect printing on base (64/40 and 65/40) (1-2% section balance)
(!!!!) (Best Value used) ECC83=12AX7 Fisher Mullard ribbed plates used/good 1964 copper grid posts (.7/.8mA Gm=1400/1500)
(!!!!) (microphonic single) 6922=E88CC Siemens Halske Germany gray shield NOS 1965 (A0 Series=1st series) (15.2/15.8ma)
(!!!!) (Recommended Pair) 403B Western Electric NOS "D" getter 1969 (5.1/5.1ma)
(!!!!) (Recommended Pair) 403B Western Electric NOS "D" getter 1969 (5.6/5.6ma) 1% matched
(!!!!) (Recommended Pair) 403B=6AK5 Western Electric NOS "D" getter 1969 (7.3/7.0ma)