(!!!!!) (INFORMATION) 6N1 or 6N1P (Best Sounding Substitutes = 6BK7B, 6BQ7A, 6BZ7)
(!!!!) (Best GE Single 1957) 6BK7A GE gray plates NOS "U" getter 1957 (9.8/10.8ma)
(!!!!) (Best GE Single) 6BK7B GE gray plates NOS "U" getter 1974 (8.0/8.8ma)
(!!!!) (Single) 6BK7B GE gray plates NOS "U" getter 1963 (6.2/5.4ma)
(!!!!) (Single) 6BK7B RCA NOS "U" getter 1950's (7.5/8.5ma)
(!!!!) (Single) 6BK7B Tungsol branded RCA "U" getter 1957 (10/14ma)
(!!!) (Recommended Pair) 6BK7B Tungsol black plates NOS "O" getter 1960 era (9.5/12ma and 9.8/10.5ma)
(!!!) (Recommended Pair) 6BK7B Tungsol black plates NOS "O" getter 1960's (7.5/8.6ma and 8.2/9.4ma)
(!!!) (Recommended Pair) 6BK7B Tungsol gray plates NOS "O" getter 1960's (10/11ma and 10.6/13.2ma)
(!!!) (Recommended Single) 6BK7A Raytheon black plates NOS "D" getter 1950's (7.2/8.2ma) (great sub for 6N1P)
(!!!) (Recommended Single) 6BK7B Tungsol gray plates NOS 1960's (8.0/9.8ma) (great sub for 6N1P)
(!) (BEST SINGLE) 5BQ7A Tungsol black plates NOS 1960 era (12.0/12.2ma) 1-2% section balance
(!) (PAIR) 5BQ7A Dumont by GE gray plates NOS 1973 "U" and "O" getter (7.0/7.4ma and 7.0/6.6ma)
(!) (PAIR) 5BQ7A Dumont by GE gray plates NOS 1973 (8.3/8.0ma and 8.6/9.8ma)
(!) (PAIR) 5BQ7A GE gray plates NOS large "U" getter halo 1961 -1964
(!) (Single) 5BK7A GE gray plates "U" getter NOS 1964 (7.5/10.5ma)
(!) (Single) 5BK7A GE gray plates "U" getter NOS 1973 (8.5/11ma)
(!) 5BQ7A RCA black plates NOS 1964 (11.6/14.4ma)
5BQ7A GE black plates "U" getter 1961 (10.8/7.0ma)
5BQ7A GE Dumont gray plates "O" getter 1973 (12.8/8.2ma)
