1 pair) ECF80=6BL8 Telefunken Germany <> bottom NOS 1971

1 tube) 11.5ma Gm=5000 and 9.6ma Gm=6000 (triode/pentode) 

1 tube) 12.2ma Gm=5200 and 9.5ma Gm=6100 (triode/pentode) 

Matched on Amplitrex

Good Triode Ma/Gm=11-14ma Gm=4500-5000

Good Pentode Ma/Gm=8-10ma Gm=5500-6000

Recommended for

- McIntosh MR67, MR71 FM Stereo tuner
- Telefunken radio
- Graaf GM 100 amplifier
- HH Scott 350 Tuner 1961-2