(!!!!!) (Best Holland Pair 1967-1968) 12AX7=ECC83 Philips and Philips Miniwatt Holland ribbed plates "O" getter halo NOS 1967-1968 (1.3/1.5ma and 1.4/1.6ma) (close Gm)
(!!!!!) (Good Value Single) 12AX7 BRIMAR BVA England narrow ribbed plates like new 1959 (1.0/1.2ma)
(!!!) 12AX7 BRIMAR England BVA ribbed plates used/good 1960's (0.8/1.0ma and Gm=1400/1500)
ECC83=12AX7 Mullard UK BVA long plates "O" getter like new 1958 (f91 series) (1.2/1.2ma)
(!!!) (Best Value Single) 12AX7 Triotron by Philips Canada NOS 1963 (1.3/1.5ma and Gm=1800/1900)(same sound as Holland)
(!!!) (Best Value Pair) 12AX7A=ECC83 Raytheon by HITACHI JAPAN NOS 1960's (1.5/1.4ma and 1.6/1.4ma) (High mA and Gm) 1-3 % matched
(!!!!) (BEST SINGLE) 12AX7A=ECC83 Matsushita Japan NOS rebranded Raytheon NOS 1970 era (Gm=1800/1800 and 1.5/1.3ma) (similar to Mullard)
(!!!!) (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) 12AX7=ECC83 Ultron SQ India (Mullard clone) ribbed plates NOS 1976 (Gm=1700/1700) 1% section balance
(!!) (Best Value) 12AX7=ECC83 Zaerix East Germany NOS 1970's (Gm=1500/1500) 1% section balance
(!!!!) (Single) E83CC=12AX7 Siemens Halske Germany NOS 1976 (0.7/0.9ma and Gm=1400/1600)
(!) (MULLARD CLONE) 12AX7=ECC83 Matsushita Japan NOS 1960's (Gm=1600/1500 and 1.2/1.0ma) (similar to Mullard)
(!!!) 7025 RCA ribbed gray plates used/tests like new 1960's faded printing (Gm=1500/1500 and 1.1/0.9mA) (V1 guitar amp)
(!!!) 7025 RCA ribbed gray plates like new 1968 (Gm=1500/1600 and 1.1/1.3mA) (V1 guitar amp)
(!!!) 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 1964 (Gm=1450/1900 and 0.8/1.6mA) (V1 guitar amp)
(!!!) 7025 RCA ribbed gray plates used/good 1972 (Gm=1450/1400 and 0.9/0.8mA) (V1 guitar amp)
(!!!) 7025 RCA ribbed gray plates used/good 1970 era faded printing (Gm=1500/1500 and 0.9/1.0mA) (V1 guitar amp)
(!!!) (Best Single) 12AX7A RCA gray ribbed plates NOS 1966 (1.0/1.0ma and Gm=1500/1500) 1% section balance
(!!) (Nice Single) 12AX7 GE NOS pinched plates 1970 (1.0/1.3ma and Gm=1600/1800)