(!!!!) (Best Pair) 6189W Sylvania NOS 1976-1979 (9.5/9.6ma and 9.2/10.2ma) 1-3% matched
(!!!!) (Best Single) GB-6189=12AU7WA Sylvania Gold Brand Gold Pins 1960's (10.6/11.2ma) (High mA and Gm)
(!!!!) (Good Value Pair) 6189=12AU7WA Sylvania NOS 1960's (8/8ma and 8.4/8.6ma) (same Gm)