EL50

Name: EL50
Brand: Philips

Power Pentode — B8A — Philips

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

↗ r-type.org ↗ TDSL ↗ Radiomuseum

Known Equivalents & Substitutes

46544654P46994699NCV2941BF45110E/131

Similar Tubes (Not Drop-In Compatible)

4689

EL5/375 — same P8A base, higher voltage rating than EL5, electrically very close to EL50

6L6

American equivalent by function (~18W beam tetrode) but Octal base and beam tetrode vs true pentode

EL11

Same electrical class (~18W pentode) but G8A Stahlröhre base — completely different socket

EL12

Same ~18W Philips pentode family, P8 base — different pin assignment, not drop-in

EL34

Later Philips power pentode (25W), Octal base — higher ratings, different socket

EL35

Same ~18W Philips pentode family but Octal (I/O) base — not P8A compatible

EL37

Higher-rated Philips pentode (~25W), Octal base — not P8A compatible

EL39

Octal base version with similar ratings — not pin-compatible with P8A/B8A base

EL3N

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)600V

Screen Voltage (max)Screen Voltage (max)275V

Anode Dissipation (max)Anode Dissipation (max)18W

Screen Dissipation (max)Screen Dissipation (max, estimated)2.5W

Typical Operating

Notes

European side-contact base (P8A/Ct8) with top-cap anode — no direct American or Octal/Noval equivalents exist.
The EL50 sits in a large Philips ~18W power pentode family spanning multiple base types: EL5/EL50 (P8A), EL35 (Octal), EL11 (G8A Stahlröhre), EL12 (P8 variants). All share similar electricals (Pa=18W, Va~375V, Gm~7-9 mA/V) but different sockets.
CV2941 is the British military designation. BF451 is listed as equivalent in the Brans Vademecum.
The EL50 belongs to the Philips all-glass P8A tube family that includes the EF50 RF pentode — described as 'next to the magnetron, the most important tube from World War II.' The EF50 was critical to British Chain Home radar; its pressed-glass base technology (shared with the EL50) was a Philips innovation that became the basis for all modern tube construction. Components for the EF50 were smuggled out of the Philips factory in Eindhoven on the eve of the German invasion of the Netherlands in May 1940.

Pin Layout — B8A

1No Connection

2Heater

3Heater

Socket-Compatible Tubes ⚠ Not electrically compatible

EL51 EL6

References