(!!!!) (Best Single) 12AU7=ECC82 Mullard UK ribbed plates NOS 1972 (12.2/13.6ma) (same Gm) (smooth rich sound)
(!!!!) (Best Value Single) 12AU7=ECC82 Mullard UK ribbed plates like new 1965 (10/12.8ma) (smooth rich sound)
(!!!!) (Recommended Pair) 12AU7A=ECC82 Mullard rebranded "GE" and "Zenith" ribbed plates NOS 1966 (9.8/11ma and 10.4/10.5ma) (smooth rich sound)
(!!!!) (Recommended Single) 12AU7=ECC82 Mullard UK ribbed plates NOS 1970 (10.4/8.6ma)(smooth rich sound)
(!!) (slightly microphonic) 12AU7A Raytheon black ribbed plates "D" getter halo black coated glass 1951 (8.8/9.6ma)
