1 low noise tube) 5687WA and 5687WB GE black plates - same build - test like new 1970's in white boxes

1 tube) 39.0/38.5ma Gm=11,400/12,000

1 tube) 37.0/41.0ma Gm=11,150/11,650

Good Ma range 30-35ma

Recommended for

Manley

Modwright

Audio Note

Ray Samuels

Ayon

Kondo

Mastersound

Audio Thrills

Loth