1 pair) 6X4 SER = LM Ericsson Sweden NOS "D" getter 1950's 1% matched in white boxes

1 tube) 53/40 and 55/40

1 tube) 53/40 and 55/40

Aktiebolaget Svenska Elektronror = Limited Company Swedish Electron Tubes

Recommended for

Audio Note DAC 1.2
LAMM LP2 phono

KONDO KSL M7 preamp
Kondo M77 preamp
Eastern Electric Minimax Phono

Pultec EQ

Wright WPP200C
Audio Note M7