6N5P — Small Signal Triode, Noval | Tubeofile

6N5P

Small Signal Triode — Noval

NEVZ (Novosibirsk)

Known Equivalents & Substitutes

1539

Similar Tubes (Not Drop-In Compatible)

6AU7

Same 9A noval pinout but different characteristics: mu=20 vs 27, gm=3.1 vs 4.2 mA/V, Pa_max=2.75W vs 2.2W

Noval double triode but completely different pinout (pins 1,2=heater vs 4,5=heater on 6N5P) — not interchangeable without rewiring

7AU7

Same noval pinout but 7V/300mA series heater instead of 6.3V/600mA

ECC804

Same noval pinout with shield on pin 9, but different characteristics: mu=17, gm=2.2 mA/V, 0.3A heater

Electrical Specifications

Absolute Maximum

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

Anode Dissipation (max)Anode Dissipation (max, per section)2.2W

Cathode Current (max)Cathode Current (max, per section)25mA

Heater-to-Cathode Voltage (max)Heater-to-Cathode Voltage (max)250V

Notes

Cyrillic designation: 6Н5П. Also transliterated as 6H5P. The 1539 is a higher-quality-class variant of the same tube.
Pin 9 is an internal shield between the two triode sections, same arrangement as 6N6P and 6N1P.
The Chinese 6N5P (different tube entirely) is a power dual triode equivalent to 6AS7/6080 with an octal base and 2.4A heater — do not confuse with this Soviet noval small-signal type.
Plate resistance (ra) is not stated directly in the datasheet but can be calculated: ra = μ/gm = 27/4.2 ≈ 6430 Ω.
Capacitance values differ slightly between the two triode sections: Cak = 1.5 pF (triode 1) vs 1.7 pF (triode 2).
Heater current (0.6A) is double that of most Western noval dual triodes (e.g. 12AU7 at 0.15A for 12.6V operation) — verify heater supply capacity before substituting in circuits designed for lower-current types.

Pin Layout — Noval

1Anode (triode 1)

2Grid (triode 1)

3Cathode (triode 1)

Socket-Compatible Tubes ⚠ Not electrically compatible

References