(!!!!!) (Recommended Single) 12AU7 Mullard UK "long plates" and "O" getter 1958 (10.8ma and 11ma) (High mA and Gm)
(!!!!) (Best Bugle Boy Single 1959) 12AU7 Amperex Bugle Boy England (Mullard) long plates with "D" getter like new 1959 (12.4/9.8ma)
(!!!!) (Long Plate Single) 12AU7 Mullard Heath UK long plates "O" getter used/good 1959 (8.8/9.0ma)
