(!!!!!) (2nd Best Pair) ECF80=6BL8 Telefunken Germany <> bottom NOS 1971 (11.5/9.6ma and 12.2/9.5ma) (best sound)
(!!!!!) (3rd Best Pair) ECF80=6BL8 Telefunken Germany <> bottom NOS 1971 (11.8/9.6ma and 11.0/8.6ma) (best sound)
(!!!!!) (Best Overall Pair) ECF80=6BL8 Telefunken Germany <> bottom NOS 1971 (12.8/12.4ma and 12.6/12.2ma) 1-3% matched (Highest mA and Gm)
(!!!!) (Best Single) ECF80=6BL8 Telefunken Germany NOS 1971 (12.5/10ma)
(!!!!) (Best Value Pair #1) 12AX7=ECC83 Telefunken Germany <> bottom branded GAP/R Computor tube <> bottom smooth plates used/good 1964 era (0.9/0.8ma and 1.0/0.8ma)
(!!!!) (Best Value Pair #1) 12AX7A RCA gray ribbed plates NOS 1967-1973 (best tone) (0.9/0.9ma and 0.9/1.1ma) (Fender)
(!!!!) (Best Value Pair #2) 12AX7=ECC83 Telefunken Germany <> bottom branded GAP/R Computor tube <> bottom smooth plates used/good 1964 era (0.8/0.8ma and 0.8/0.8ma)
(!!!!) (Good Value Pair) 12BH7A GE NOS gray oval plates "o" getter halo 1961-1965 (7.2/6.6ma and 8.4/6.8ma)
(!!!!) (Single 1950's) 12BH7A RCA branded Westinghouse narrow black plates NOS "U" getter mid-1950's (10.6/7.4ma) (1st series made)
(!!!!) (Single 1955 era) 12BH7A RCA narrow black plates used/very good "U" getter halo 1955 era (8.6/10ma) (1st series made) (rare)
(!!!!) (Single) 12BH7A GE gray oval plates NOS mid-1960's (11.5/16ma)
(!!!!) (Single) 12BH7A Sylvania NOS gray oval plates NOS 1965 era (8.2/8.4ma) 1-3% section balance
(!!!!) (Single) ECF80=6BL8 Telefunken Germany NOS 1971 (11.7/9ma)
(!!!) (BEST EM87) EM87 Valvo Germany branded Telefunken Germany NOS 1961 (2 in stock)
(!!!) (Best Mullard Single) ECF80=6BL8 IEC Mullard UK NOS 1966 (16ma/12ma) (Highest mA and Gm)
(!!!) (Best Value Pair) 6BL8 Motorola Golden JAPAN by Toshiba "Premium Rated" NOS 1974 (1 pair)
(!!!) (Best Value) 12AX7A RCA gray ribbed plates "O" getter halo NOS 1965 (1.0/0.8mA and Gm=1600/1400)
(!!!) (Good Value) 12AX7A RCA gray ribbed plates "O" getter halo NOS 1973 (1.0/0.9mA and Gm=1400/1550)
(!!!) (Recommended Pair) 12AZ7A GE Admiral black plates NOS 1960 (10/9ma and 9.2/10.5ma) (McIntosh MC275)
(!!!) (Recommended Pair) 12AZ7A GE gray plates NOS 1969-1970 (8.2/8.0ma and 8.7/8.8ma) (McIntosh MC275)