(!!!) (BEST PAIR) ECC808=6KX8 Telefunken Diamond Bottom NOS 1963-1966 (1.1/1.3ma and 1.3/1.0ma)1 matched pair) ECC808=6KX8 Telefunken Diamond Bottom NOS 1963 1966 in white boxes 1 tube) 1. 1 1. 3ma Gm=1500 1600 1963 1 tube) 1. 3 1. 0ma Gm=1600 1500 1966 Matched on Amplitrex Vplate=250V Vgrid= 1. 9V Good Ma = 1. 0 1. 2ma Good Gm = 1500 1600 B=Berlin Tubes were "Factory Sealed " (5 are used in the 4 Channel Echolette PA amp made in Germany)