417A

Small Signal Triode — Noval

Western Electric

Known Equivalents & Substitutes

5842

Similar Tubes (Not Drop-In Compatible)

12AT7

Noval medium-mu triode (mu=60) but twin triode with higher ra (10900 ohms); different pinout

6AK5

Noval miniature tube used in similar telecom/instrumentation applications but is a pentode

6C45Pi

Single noval triode with very high gm and low ra; similar high-current low-impedance design philosophy

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Max. Plate Voltage200V

Anode Dissipation (max)Max. Plate Dissipation4.5W

Cathode Current (max)Max. Cathode Current38mA

Heater-to-Cathode Voltage (max)Max. Heater-Cathode Voltage55V

Typical Operating

Notes

Originally designed by Western Electric for telephone repeater amplifier service.
The 5842 is the RETMA/JAN designation for the same tube as the 417A.
Single triode despite the Noval base; pins 4, 5, 7, and 8 are all connected to the grid for low inductance.
Very low plate resistance (1700 ohms) and high transconductance (25 mA/V) make it suitable as a low-impedance driver.
Widely used in high-end audio preamplifiers and microphone preamps.
Coated unipotential cathode; may be operated in any position.
RCA datasheet dated March 1962.

Pin Layout — Noval

1Plate

2No Internal Connection

3Heater

References