(!!!) (Recommended Pair) 6GK5=6FQ5A Toshiba Japan rebranded Raytheon NOS (8.7ma and 9.7ma)

1 pair) 6GK5=6FQ5A Toshiba Japan rebranded Raytheon NOS 1970 era

1 tube) 8.7ma Gm=12,300

1 tube) 9.7ma Gm=13,000

Tested on Amplitrex

Good Ma range 9-11ma

Good Gm range 13,00-15,000

– Conrad Johnson Premier 10, 14 preamp and DAC
– Supratek
– Wright