(!!!!) (Recommended Pair) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (9.8/11ma and 10/10.9ma) 1-2% matched
(!!!!) (Recommended Pair) ECC82=12AU7 Telefunken Diamond Bottom ribbed plates used/tests like new 1960's (9.2ma/8.4ma and 9.3/9.4ma)
(!!!!) (Recommended Pair) ECC82=12AU7 Telefunken Germany <> Bottom smooth plates NOS 1960's - 1970 faded printing (8.2ma/8.6ma and 8.8/9.2ma)
(!!!!) (Recommended Pair) JAN-6189W=12AU7WA Sylvania NOS 1972-1973 (9.6/10.6ma and 9.3/10.4ma) 1-3% matched
(!!!!) (Recommended Single) 12AU7=ECC82 Mullard UK ribbed plates NOS 1963 (11.4/9.6ma) (smooth rich sound)
(!!!!) (Recommended Single) 12AU7=ECC82 Mullard UK ribbed plates NOS 1970 (10.4/8.6ma)(smooth rich sound)
(!!!!) (Recommended Single) 12AU7=ECC82 Mullard UK ribbed plates NOS 1972 (12.2/13.6ma) (same Gm) (smooth rich sound)
(!!!!) (Recommended Single) 12AU7A Sylvania NOS 1960's (10/2/11.2ma)
(!!!!) (Recommended Single) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (8.6/11.3mA)
(!!!!) (Recommended Single) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (9.4/11.3mA)
(!!!!) (Recommended Single) CV491=12AU7=ECC82 Brimar UK NOS ribbed plates large "O" getter halo 1966 (9.4/10.4ma)
(!!!!) (Recommended Single) ECC82=12AU7 Telefunken Diamond Bottom ribbed plates like new 1960 (14.0/11.2ma) (Close Gm) (Highest mA and Gm)
(!!!!) (Single 1955) 12AU7 Brimar UK NOS gray ribbed plates "D" getter halo 1955 (8.2/10.4ma)
(!!!!) (Single 1959) ECC82=12AU7 Philips Miniwatt Holland like new low hours/tests like new 1959 (10.6/9.8ma)
(!!!!) (Single 1964) ECC82=12AU7 Miniwatt Philips Canada NOS 1964 (9.2/9.8ma) (same build as Holland)
(!!!!) (Slightlly microphonic single) JAN-CHS-12AU7 Sylvania "black plates" with "D" getter halo NOS 1951 (9.8/10ma)
(!!!) (Best 5-Star) 5814A=12AU7 GE Electronic Secretary "5 STAR" triple mica NOS 1960 (10.8/10.4ma) (Same Gm)
(!!!) (Best Mullard Single) 12AU7=ECC82 Mullard rebranded Philips ribbed plates NOS 1970 (10.2/10.0mA) 1-2% section balance
(!!!) (Best Overall Pair) 5963=12AU7 Sylvania NOS 1960's (10/10.6ma and 10/10.6ma) 1% matched
(!!!) (Best Pair) 5963=12AU7 Sylvania NOS 1960's (11.4/11.2ma and 11.2/11.4ma) (same Gm) 1% matched