1 low noise tube) 5687 Tungsol branded Amperex black plate/bronze-black plate 1960's - 1 plate has a hint of bronze color

38.5ma Gm=11,200

43ma Gm=12,600

Good Ma range 30-35ma

Tested on Amplitrex

Recommended for

Manley

Modwright

Audio Note

Ray Samuels

Ayon

Kondo

Mastersound

Audio Thrills

Loth