(!!!!!) (2nd Best Single 1958) 12AX7=ECC83 Mullard UK "long plates" NOS 1958 (1.3/1.4ma) (f91 series)
(!!!!!) (Best Single 1956) 12AU7=ECC82 Amperex Holland "long-plates" large "D" getter with crossbar like new 1956 (9.2/8.2ma) (rare)
(!!!!!) (Good Value Single) 12AU7=ECC82 Mullard UK long plates "O" getter halo used/good 1958 (9.0/8.8ma)
(!!!!!) (Recommended Single) 12AU7 Mullard UK "long plates" and "O" getter 1958 (10.8ma and 11ma) (High mA and Gm)
(!!!!) (Best Bugle Boy Single 1959) 12AU7 Amperex Bugle Boy England (Mullard) long plates with "D" getter like new 1959 (12.4/9.8ma)
(!!!!) (Best Pair) 12AU7A RCA clear top "D" getter NOS 1959-1965 (10.6/10.6ma and 11.6/11.7ma) (Highest mA and Gm) (close Gm)
(!!!!) (Good Value Single) ECC83=12AX7 Amperex Bugle Boy Holland "long plates" and "D" getter used/good 1958 (1.1/1.1ma and Gm=1350/1350) 1% section balance
(!!!!) (Holland single 1958) ECC83=12AX7 Triotron Holland "long plates" with "D" getter halo like new 1957 (1.1/1.2ma and Gm=1700/1700)
(!!!!) (Long Plate Single) 12AU7 Mullard Heath UK long plates "O" getter used/good 1959 (8.8/9.0ma)
(!!!) (Good Value) 12AX7 RCA "long gray plates" with "D" getter used/good 1960 good printing (0.6/0.7mA and Gm=1400/1500)
(!!!) (Recommended Single) 12AX7 RCA "tall gray plates" and "D" getter halo branded Raytheon used/good 1950's (Gm=1900/2100) (1.3/1.7ma)
(!!!) (SINGLE) 12AU7=ECC82 RT Radio Technique France long plates 1958-1959 (11.6/9.8ma) (close Gm)
(!!!) 12AX7=ECC83 Mullard UK "long plates" with "D" getter used/50-60% (0.6/0.7ma Gm=900/1000 - low Gm) (mC1 series)
(!!) (SINGLE) 12AU7 RCA long plates D getter NOS 1950's (9.2/9.8ma)
(!!) 12AU7A CBS black plates NOS 1960 era (9.5/11.8ma)
ECC82=12AU7 Siemens Halske "Long Ribbed Plates" and "O" getter NOS 1958 (10.4/11.8ma)
ECC83=12AX7 Mullard UK BVA long plates "O" getter like new 1958 (f91 series) (1.2/1.2ma)
