(!!!!!) (Recommended Pair) E80CF=7643 Valvo branded Philips Miniwatt SQ NOS 1963 (PREMIUM 6BL8 SUB) (Tuners)1 matched pair) E80CF=7643 Valvo branded Philips Miniwatt SQ NOS 1963 (Triode Pentode) 1 3% matched in white boxes 1 tube) 11. 3ma Gm=4600 and 9. 5ma Gm=6300 1 tube) 11. 6ma Gm=4600 and 10. 4ma Gm=6000 Good Triode section Ma and Gm = 11 13ma Gm= 4500 5000 Good Pentode section Ma and Gm = 9 11ma Gm = 6000 6500 7643=E80CF is a "SPECIAL QUALITY" low noise medium mu triode pentode Specs are similar to 6BL8=ECF80 McIntosh MR 67 tuner