GZ31

Rectifier — Octal

Mullard

Known Equivalents & Substitutes

5AS45AS4ACV3440

Similar Tubes (Not Drop-In Compatible)

Russian equivalents reference lists 5C3S as equivalent to both 5U4G and GZ31 — similar full-wave rectifier but directly heated, different characteristics

GZ32

Similar Mullard rectifier on Octal base but different voltage/current ratings

GZ34

Higher-current Mullard rectifier (5AR4) on Octal base — not directly interchangeable due to higher current ratings

Electrical Specifications

Absolute Maximum

Anode Voltage (max)AC Plate Voltage (max, per plate)350V

Rectifier

DC Output Current (max)DC Output Current (max)225mA

Heater

Heater VoltageHeater Voltage5V

Heater CurrentHeater Current

Notes

The GZ31 is the Mullard/Philips designation for a full-wave rectifier. The 5AS4A is the American RETMA equivalent.
Indirectly heated cathode with 5V heater. Sams lists 5U4G as a substitute.
Soviet equivalent 5C3S (5Ц3С) covers both 5U4G and GZ31 according to the Russian equivalents reference.

Pin Layout — Octal

1No Connection

2Heater

3Anode 1

4

Socket-Compatible Tubes ⚠ Not electrically compatible

AZ31

References