7643 Valvo branded Amperex PQ Germany "PINCHED WAIST" NOS 1960 (6BL8 sub)

7643 Amperex Germany "PINCHED WAIST" NOS Gold Pins made by Valvo Hamburg Germany (BG2-D0J1=1960) date code on bottom of tube (Triode/Pentode)

triode) 11.5ma Gm=4600 

pentode) 7.0ma Gm=5400

Good Triode section Ma and Gm = 10-13ma Gm= 4500-5000

Good Pentode section Ma and Gm = 9-11ma Gm = 6000-6500



(The E80CF is a "SPECIAL QUALITY" medium-mu triode/pentode. Specs are similar to 6BL8=ECF80)

- McIntosh MR-67 tuner