Different Noval pin assignments — EL84 has g1 on pin 2, k on pin 3, a on pin 7, g2 on pin 9; 6P18P (EL82-family) has g1 on pins 3 and 9, k on pin 4, a on pin 7, g2 on pin 8. Not a drop-in substitute despite both being 6.3 V Noval output pentodes.
Pins 3 and 9 are both control-grid (g1) terminals — the dual connection suppresses HF parasitic oscillations, a common feature on TV vertical-output pentodes in this family.
Higher anode dissipation rating than EL82 (12 W vs 9 W) — the 6P18P is the more rugged Soviet version of the EL82, but pin layout and electrical characteristics are otherwise compatible.
Russian datasheets list μ = 13 as the screen-to-control-grid amplification factor (μg2/g1), not a triode μ. This is normal for output pentodes and cannot be substituted into mu ≈ gm × ra.
Pulse anode voltage rating: 2500 V positive / -500 V negative. Cathode-heater voltage limit: 100 V.
Often marketed as an EL84 substitute, but EL84 has a completely different Noval pin layout — see similar entry.
Pin Layout — Noval
1No Connection (internal screen)
2Suppressor Grid (internally connected to cathode)
3
Socket-Compatible Tubes ⚠ Not electrically compatible