(!!) 13D3 Brimar UK black plates tests like new 1962 (6.8ma/7.2ma) (similar to 12AU7)

1 tube) 13D3 Brimar UK black plates tests like new 1962 (6.8ma/7.2ma) in white box

similar to 12AU7

1 section) 6.8ma Gm=2400

1 section) 7.2ma Gm=2400

Amplitrex Test Data

Vplate=250V

Vgrid=-4.6V

Good Iplate (ma) = 6ma

Good Gm = 2200-2400