(!!!!) (Recommended Pair) ECC81=12AT7 Mullard UK branded Raytheon NOS 1972 (9.2/13.8ma and 9.3/12.5ma) 1-5% matched
(!!!) (Good Value Pair) ECC81=12AT7 IEC Mullard used/good 1967 (6.8/7.0ma and 7.0/7.2ma) (Jolida, Fender)
12AT7=ECC81 Mullard low hours/like new 1970 (8.0/8.4ma)
