Known Equivalents & Substitutes
No known equivalents. If you know of any, use the ⚑ Report Issue button above.
Similar Tubes (Not Drop-In Compatible)
A11D
Radiomuseum lists as similar rectifier alternativeIW4
Same family but lower voltage rating — not interchangeable if circuit requires 350V ratingR2
Radiomuseum lists as similar rectifier alternativeElectrical Specifications
Absolute Maximum
Anode Voltage (max)Max AC Voltage per Anode (RMS)350V
Rectifier
DC Output Current (max)Max DC Output Current120mA
Heater
Heater VoltageHeater Voltage4V
Heater CurrentHeater Current2A
Notes
- Half-indirect heating — a transitional cathode design between direct and fully indirect heating.
- European B4 (4-pin) base with 4V/2A filament.
- Valve Equivalents reference lists as 'Double Diode' with B4 base and 4V heater.
- Used in 66 documented radio models (1936-1946) per Radiomuseum.
- Also referred to as 1W4/350 in some references (Taschenbuch 1948/49).
Pin Layout — B4
1Anode 1
2Heater/Cathode
3Anode 2
4Heater/Cathode
Socket-Compatible Tubes ⚠ Not electrically compatible