EF86

Small Signal Pentode — Noval

Philips

Known Equivalents & Substitutes

62676BK86F22CV2901Z729EF806S

Similar Tubes (Not Drop-In Compatible)

Soviet equivalent (6Ж32П) — same B9A base, verify exact pin compatibility before substituting

Series-heater version (25V/0.3A) — not compatible with 6.3V parallel heater circuits

12.6V heater variant — different heater requirements

Electrical Specifications

Section 1 — Pentode

Absolute Maximum

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

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

Anode Dissipation (max)Anode Dissipation (max)1W

Screen Dissipation (max)Screen Dissipation (max)0.2W

Notes

Pins 1 and 7 are internal metallic shields for hum and noise reduction — must be grounded for lowest noise performance.
Pin 2 (g3/suppressor) is internally connected to cathode; separate pin allows external connection if needed.
Equivalent noise voltage: approx. 2 µV (25–10,000 Hz bandwidth) at Vb = 250 V, Ra = 100 kΩ.
Vhk_max is asymmetric: 100 V (cathode positive of heater) / 50 V (cathode negative of heater).
Rg_max depends on anode dissipation: 10 MΩ for Wa < 0.2 W, 3 MΩ for Wa > 0.2 W. The 10 MΩ figure applies to typical low-level audio preamp use.
PF86 (series heater) and UF86 (12.6 V heater) are pin-compatible variants with different heater ratings.
Triode connection operating data on Philips datasheet page 3: three RC-coupled amplifier configurations documented at supply voltages from 100–400 V. Small-signal triode characteristics (μ, gm, ra) from Tom Schlangen measurements, consistent with Philips stage-gain data.

Pin Layout — Noval

1Screen Grid

2Internal Shield

3Cathode

Socket-Compatible Tubes ⚠ Not electrically compatible

References