6X4 SER = LM Ericsson Sweden NOS "D" getter 1950's slightly faded top getter

Aktiebolaget Svenska Elektronror = Limited Company Swedish Electron Tubes

54/40

55/40

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

DIY