(!!!!) (Recommended Pair) ECC83=12AX7 Tungsram Hungary branded IEC Mullard NOS 1982 (1.5/1.6ma and 1.4/1.7ma)
(!!!!) (Recommended Single) 12AX7 Brimar BVA England narrow ribbed plates used/good 1959 (1.1/1.0ma and Gm=1450/1350)
(!!!!) (Single 1955) 12AU7 Brimar UK NOS gray ribbed plates "D" getter halo 1955 (8.2/10.4ma)
(!!!!) (Slightly microphonic single) 12AX7=ECC83 Mullard UK branded Philips ribbed plates NOS 1962 (161 Series) (1.0/1.2ma and Gm=1600/1650)
(!!!) (Best Single 1966) 12AX7A RCA ribbed plates NOS 1966 (Gm=1800/1600, 1.3/1.0ma) (best tone, 2nd best to Mullard)
(!!!) (Best Value Single) 12AX7 Fisher Telefunken ribbed plate used/good 1960 era fair printing (Gm=1400/1600 and 0.9/1.1ma)
(!!!) (Best Value Single) 12AX7=ECC83 Mullard UK ribbed plates used/good 1967 (1.7/0.8ma and Gm=2000/1600) (V1 guitar amp)
(!!!) (Good Value Single) 12AX7=ECC83 Mullard GE UK ribbed plates used/good 1966 (.8/.9ma and Gm=1450/1600)
(!!!) (Good Value Single) 12AX7A RCA Magnavox ribbed plates used/good 1961 (Gm=1500/1900 and 0.8/1.3ma)
(!!!) (Good Value Single) 12AX7A RCA ribbed plates NOS 1974 (Gm=1600/1400, 1.1/0.8ma)
(!!!) (Good Value Single) 12AX7A RCA ribbed plates used/good 1960's faded printing (Gm=1400/1700 and 0.8/1.1ma)
(!!!) (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 1962) ECC83=12AX7 Mullard Webcor ribbed plates used/very good 1962 (161 series) in white box (1.0/1.1ma and Gm=1600/1600)
(!!!) (Recommended Single) ECC83=12AX7 Mullard Webcor ribbed plates used/good 1962 (161 series) in white box (1.0/0.7ma and Gm=1600/1400)
(!!!) (Recommended Single) JRP-12AX7 Raytheon Black Plates NOS 1962 (Gm=1450/1600) (1.0/1.3ma)
(!!!) 12AU7=ECC82 Brimar BVA UK ribbed plates like new 1958 (8/9ma)
(!!!) 12AX7=ECC83 Mullard UK "long plates" with "D" getter used/50-60% (0.6/0.7ma Gm=900/1000 - low Gm) (mC1 series)
(!!!) 7025 RCA Beckman ribbed gray plates used/60% 1960's (Gm=1100/1300 and 0.5/0.7mA)
(!!!) 7025 RCA ribbed gray plates low hours/tests like new 1960's faded printing (Gm=1500/1800 and 0.9/1.3mA) (V1 guitar amp)
(!!!) 7025 RCA ribbed gray plates used/good 1960's (Gm=1350/1450 and 0.7/0.8mA)
