6350 Sylvania black plates NOS, "U" getter halo 1956, faded printing 

1 section) 11.5ma Gm=4900

1 section) 14.5ma Gm=5400

Tested on Amplitrex

Vplate=150V

Vgrid=-5V

Good Ma per section = 9-11ma

Good Gm per section = 4500-5000

Recommended for

- VTL Wotan MB1250, VTL MB450, VTL MB300, VTL 225 Deluxe, VTL Deluxe 140, VTL Stereo 120/50, VTL ST150
- VTL Siegfried
- Joule Electra LA-150 (mk2)

- Joule Electra LA 100 Mk.III

- Shindo-lab Corton