(!!!!) (Best Overall Single) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (13/12.8ma) (Highest mA and Gm)
(!!!!) (Best Pair 1955) CV378=GZ37 Mullard "D" getter NOS 1955 faded printing (56-56/40 and 57-57/40 x 2 tubes)
(!!!!) (BEST PAIR) 5R4GYB RCA and RCA branded Westinghouse NOS 1961-1970 (50-52/40 and 50-53/40)
(!!!!) (Best Pair) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (10.2/11.2ma and 10.4/11.2ma) 1-2% matched
(!!!!) (Best Quad) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (8.8/9.5, 8.8/9.4, 9.0/9.3, 9.0/9.4mA) (Highest Gm 1-2% matched)
(!!!!) (Best Single 1965) ECC82=12AU7 Miniwatt Holland like new 1965 (9.4/9.4ma) 1% section balance
(!!!!) (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) 12AX7=ECC83 Telefunken Germany <> bottom smooth plates used/good 1960's (0.8/0.8ma and 0.8/1.0ma)
(!!!!) (Best Value Single) 12AX7 Raytheon Black Plates NOS 1962 (.9/1.1ma and Gm=1400/1600)
(!!!!) (Best Value Single) 6550 Tungsol branded Sylvania smooth gray plate used/tests like new 1960 era (138ma)
(!!!!) (Best Value Single) ECC803S=12AX7 Telefunken Ulm Germany <> bottom NOS 1961 1-2% section balance (Gm=1550/1600) (1.1/1.1ma)
(!!!!) (Best Value Single) GZ34=5AR4 Philips Mullard NOS 1979 (57/40 and 58/40)
(!!!!) (Best Value used) ECC83=12AX7 Fisher Mullard ribbed plates used/good 1964 (.8/1.2mA Gm=1400/1600)
(!!!!) (Best Value used) ECC83=12AX7 Fisher Mullard ribbed plates used/good 1964 copper grid posts (.7/.8mA Gm=1400/1500)
(!!!!) (Best Westinghouse Single) 6SN7GTB Westinghouse USA black plates NOS 1963 (8.2/8.0ma)
(!!!!) (Good Value Pair 1960's) 12AX7A RCA gray ribbed plates NOS 1967 (best tone) (1.0/0.8ma and 1.0/0.8ma) (1-2% matched)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1300/1500) (0.7/1.0ma)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1300/1600) (0.7/1.1ma)
(!!!!) (Good Value Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1500/1700) (0.9/1.2ma)
(!!!!) (Holland Single) 12AU7 Philips Holland NOS 1971 dimpled disc halo (10.2/10.6ma)
