5U4GB Tungsol used/good 1960 some white oxide flakes inside tube flaked off filament wires

51/40

60/40

Tested on TV-7D/U

Recommended for

– SET amps
– Wright Sound SET
– Audio Note P4 Balanced mono amps
– Dared MCP7 preamp with phono
– Singlepower
– Modwright Transporter
– Donald North Audio