(!!!!!) (Recommended Single) ECC83=12AX7A Tungsram Hungary branded RCA NOS 1970's (Gm=1700/1900) (1.0/1.4ma)
(!!!!) (Best Pair) 12AU7=ECC82 Mullard Philips UK ribbed plates NOS 1974 same date codes 1-2% matched (9.8/10.2ma and 9.8/10.0ma) (Rogue, Hovland, Audio Note)
(!!!!) (Best Pair) 12AU7=ECC82 Mullard Philips UK ribbed plates NOS 1974 same date codes 1-2% matched (9.8/9.6ma and 9.6/10.0ma) (Rogue, Hovland, Audio Note)
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.3/1.6ma and 1.4/1.6ma) 1-3% matched (high Gm)
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.4/1.4ma and 1.4/1.4ma) 1-2% matched
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.4/1.5ma and 1.4/1.5ma) 1% matched
(!!!!) (Best Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.5/1.4ma and 1.5/1.4ma) 1% matched
(!!!!) (Best Single 1961) 12AX7=ECC83 Mullard UK ribbed plates NOS 1961 (161 Series) (1.1/1.1ma and Gm=1600/1700)
(!!!!) (Best Single 1975) 12AX7=ECC83 Mullard England ribbed plates NOS 1975 (163 Series) (1.3/1.4ma and Gm=1800/1800)
(!!!!) (BEST SINGLE) 12AX7A=ECC83 Matsushita Japan NOS rebranded Raytheon NOS 1970 era (Gm=1800/1800 and 1.5/1.3ma) (similar to Mullard)
(!!!!) (Best Single) ECC82=12AU7 Telefunken Diamond Bottom ribbed plates like new 1960 (10.6/10.2ma) (same Gm)
(!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1600/1700) (1.1/1.3ma)
(!!!!) (Best Tungsram Single) ECC83=12AX7 Tungsram Hungary NOS 1982 (1.6/1.5mA and Gm=2100/2000) (high Ma and Gm)
(!!!!) (Best Value Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1500/1600) (0.9/1.0ma)
(!!!!) (Best Value Single) ECC83=12AX7 Tungsram Hungary NOS 1980 (Gm=1500/1800) (0.9/1.2ma)
(!!!!) (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)
(!!!!) (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)