(!!!!!) (BEST BLACK PLATE PAIR + BEST VALUE) EL37 Mullard black plates double "O" getter halos 1957-1960 same build (79ma and 78ma) 1-2% matched
(!!!!!) (BEST OVERALL PAIR) EL37 Mullard NOS black base and brown base gray plate same build NOS 1962-1966 (93ma and 96ma)
(!!!!!) (BEST VALUE PAIR) EL37 Mullard low hours/like new Ma and Gm, gray plate, same build 1963-1969 (75ma and 79ma)
(!!!!) (BEST BROWN BASE PAIR 1960's) EL37 Mullard NOS brown base gray plate NOS 1962-1966 (77ma and 85ma) (close Gm matching)
(!!!!) (BEST PAIR) EL37 Mullard black base gray plate NOS early 1960's (76ma and 80ma) (close Gm matching)
(!!!!) (BEST VALUE PAIR 1950's) EL37 Mullard black plates used/good 1956-1957 (73ma and 76ma)
(!!!) (#1 EL37 Mullard single from 1955) EL37 Mullard black plate NOS 1955 (106ma) (tested on Amplitrex) (highest Ma and Gm)
(!!!) (~ Recommended EL37 Single ~) EL37 Mullard black plate NOS (2) upside-down cup-shape getter halos (74ma)
(!!!) (~ Recommended EL37 Single ~) EL37 Mullard gray plate NOS "O" getter halos 1962 in white box (85.5ma)
(!!) (#1 EL37 single from 1955) EL37 Mullard like new gray plate, 1 upside-down "cup shape" getter halo, made on or before 1955 (91ma) (tested on Amplitrex)
(!) EL37=CV586 Mullard black plate NOS 1950-1955 (76ma) (tested on Amplitrex)
EL37 Mullard black plate used 1957 (63ma) (tested on Amplitrex)
EL37 Mullard branded Philips Miniwatt gray plate like new, small rattle inside base, made before 1955 (81ma on Amplitrex AT1000)
EL37 Mullard gray plate NOS 1960's (59ma) (tested on Amplitrex)
EL37 Mullard gray plates used double "O" getter halos 1960's (60ma) (tested on Amplitrex)
EL37 Mullard used/50-55% output 1956 (52.8ma on Amplitrex AT1000)
