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

1 tube) 11.8ma Gm=5100 and 9.6ma Gm=6100 (triode/pentode) 

1 tube) 11.0ma Gm=4900 and 8.6ma 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