EF53

Name: EF53
Brand: Philips

Small Signal Pentode — Loctal — Philips

Data: HighHigh quality — base, heater, all universal parameters present, and ≥50% of desirable parameters filled in. Safe to use for design decisions.

↗ TDSL ↗ Radiomuseum

Known Equivalents & Substitutes

VR91A

Similar Tubes (Not Drop-In Compatible)

EF50

Earlier version (VR91) — same B9G base but inferior performance and higher noise; not all circuits will work with direct substitution

EF54

Similar B9G pentode with different operating point — verify characteristics before substituting

EF91

Functional successor on B7G miniature base — different pinout, not plug-compatible

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)300V

Screen Voltage (max)Screen Voltage (max)200V

Anode Dissipation (max)Anode Dissipation (max)2.5W

Screen Dissipation (max)Screen Dissipation (max)0.5W

Heater-to-Cathode Voltage (max)

Notes

The EF53 is an improved version of the EF50 with higher gm and better noise performance.
B9G (Loctal) base has a central locating spigot and locking mechanism — requires the correct Loctal socket.
Pin 5 (metallising/shield) must be grounded for proper screening and lowest noise.
Widely used in British military radar equipment as VR91A during WWII.
Datasheet not available from frank.pocnet.net; specifications from Philips published data and cross-referenced with Brans Vademecum and valve equivalents references.

Pin Layout — Loctal

1Suppressor Grid (g3)

2Heater

3Anode

References