EL81

Name: EL81
Brand: Philips

Power Pentode — Noval — 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

6CJ6CV2721CV10326N152

Similar Tubes (Not Drop-In Compatible)

PL81

Series-heater equivalent (300mA) — not compatible with 6.3V parallel heater circuits

Electrical Specifications

Section 1 — Pentode

Absolute Maximum

Anode Voltage (max)Anode Voltage (max)250V

Screen Voltage (max)Screen Voltage (max)250V

Anode Dissipation (max)Anode Dissipation (max)8W

Screen Dissipation (max)Screen Dissipation (max)4.5W

Notes

PL81 is the 300 mA series-heater equivalent (different heater specification, not a direct drop-in for 6.3 V parallel heater circuits).
Anode and screen dissipation limits are jointly defined by a combined Wa + Wg2 graph; TDSL lists Pa_max = 8 W and Ps_max = 4.5 W as individual limits.
Pins 6, 7, and 8 are internal connections (ic) per the Philips datasheet pinout diagram and must not be externally wired.
Va_max of 250 V applies to continuous operation as an A.F. amplifier; in line output (deflection) service, Va up to 550 V and Vs up to 550 V are permitted with appropriate pulse duty-cycle limits (max 22% of cycle, max 18 µs).
Triode-strapped data sourced from diyAudio forum discussion citing Philips EL81 datasheet (https://www.diyaudio.com/community/threads/is-the-6888-tube-worth-messing-with.356750/page-2), not directly visible in the fetched datasheet pages.

Pin Layout — Noval

1Cathode

2Control Grid (g1)

3Heater

Socket-Compatible Tubes ⚠ Not electrically compatible

AL860 PL81

References