(!!!) (Best Mullard Single) 6688=E180F Mullard branded Philips SQ gold pins NOS 1971 (11.5ma)
(!!!) (Best Pair) 713A Western Electric by Tungsol NOS 1942-1943 (7.1ma and 7.0ma) (713A=717A with black base)
(!!!) (Best Single #2) 6688=E180F Amperex PQ USA NOS 1965 (15.2ma)
(!!!) (Recommended Pair) 713A Western Electric by Tungsol NOS 1942-1943 (6.6ma and 6.9ma) (713A = 717A with black base)
(!!!) (Single) 6688=E180F Amperex PQ USA NOS "O" getter 1968 (9ma)
(!!) (PAIR) 713A Western Electric by Tungsol NOS 1942-1943 (6.2ma and 6.3ma)
6688 GE 5 Star used/good (7.2ma)
6688 GE NOS 1966 (9ma)
6688=E180F National UK black plate NOS probably made by Amperex (9ma)
6688=E180F National UK gray plate NOS probably made by Amperex (16ma)
