6N6P

The 6N6P, designated 6Н6П in Cyrillic, is a double triode intended for low-frequency power amplification. The Russian manual also documents its use in pulse circuits. The two sections have separate cathodes and are enclosed in a glass bulb with a nine-pin Noval base; heating is indirect, with oxide-coated cathodes. The first triode's anode, grid and cathode connect to pins 1, 2 and 3, and the second section's to pins 6, 7 and 8; the heater uses pins 4 and 5 and the shield pin 9. This last pin is not a heater centre tap. The manual permits any mounting position.

The bilingual data sheet specifies a 6.3 V heater drawing 750 ±70 mA. At an anode voltage of 120 V and a grid voltage of −2 V, each triode has a nominal current of 28 mA, transconductance of 11.2 mA/V, amplification factor of 22 and internal resistance of 1.8 kΩ; these describe the test operating point, not the gain or output power of a particular amplifier. The Russian manual instead gives 30 mA, 11 mA/V and an amplification factor of 20 under the same nominal conditions: both sets must retain their source attribution. The bilingual sheet's limits include an anode voltage of 300 V, dissipation of 4.8 W per anode and 8 W for the two together: the combined limit prevents simply adding the individual maxima. Permissible currents are 45 mA per cathode and 40 mA per triode anode. The 450 V rating applies to the tube at cutoff, with anode current no greater than 5 µA and grid voltage no greater than −50 V; it is not a normal operating voltage.

Among the documented features, the bilingual sheet specifies an ambient operating range of −60 to +70 °C, resistance to vibration up to 2.5 g, single shocks up to 500 g and repeated shocks up to 12 g. It states a guaranteed service life of 2000 hours, whereas the Russian manual gives at least 500: these are specifications in their respective sources, not a promise of remaining life for specimens available today. The cathode-to-heater limit also differs: 100 V in the bilingual sheet and 200 V in the manual. A practical design therefore requires the documentation applicable to the particular tube. Documentary sources: bilingual 6Н6П data sheet, pp. 25–28, with static and pulse characteristics; Russian technical manual, figures 331–332.