What is the 417A vacuum tube?

The 417A is a triode vacuum tube designed for phono / preamp applications. Same as 5842..

What is a 417A substitute or equivalent?

Direct equivalents to the 417A include 5842. These share the same pinout and operating envelope, so they can usually be swapped without circuit changes — though batch-to-batch variations between manufacturers (NOS vs current production) may shift the sonic character noticeably.

What are the key specifications of the 417A?

Amplification factor μ ≈ 43, transconductance gm ≈ 25 mA/V, plate resistance rp ≈ 1.7 kΩ, max plate voltage 200 V, max plate dissipation 4.5 W, heater 6.3 V / 0.3 A.

Is the 417A still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 417A as Collector availability. NOS (new-old-stock) examples from RCA, Mullard, Tung-Sol, GE, Sylvania and Telefunken trade among collectors; modern production where it exists comes mostly from JJ Electronic, Electro-Harmonix, Tung-Sol (New Sensor), Genalex, and a handful of small-batch makers.

What does the 417A sound like?

Same as 5842.. Sonic character also depends heavily on the circuit operating point, the surrounding tubes in the stage, and the output transformer when present — use the interactive loadline calculator on this page to explore the trade-offs.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

←417A

← 3A5 421A →Compare → 5842

417A Triode Vacuum Tube

Triode6.3V / 0.3A9-pin NovalSPICE

SourceWestern ElectricReviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

417A — Western Electric — triode vacuum tube — (1956)

1.7kΩ

25.0mA/V

9.0pF

1.8pF

0.55pF

GAIN43%

POWER11%

DRIVE98%

LINEARITY79%

SPECIFICATIONS

Heater6.3 V · 0.3 A

Max Plate Voltage200 V

Pa max4.5 W

Gain Factor43

gm25 mA/V

rp1.7 kΩ

Inter-electrode capacitances

Cgk9 pF

Cgp1.8 pF

Cpk0.55 pF

Pinout9-pin Noval

Era1956

RarityCollector

HEATER6.3V / 0.3A

MAX PLATE200V / 4.5W

BASEnoval

Source datasheets

4 manufacturer datasheets cross-checked for 417A

4 verified

TYPICAL OPERATING POINT

Va105V

Ia14.22mA

Vg-1.5V

Pd1.49W

RL4kΩ

Av28.3dB

EXECUTIVE SUMMARY

The 417A is a indirectly-heated triode from Western Electric, introduced around 1956. It provides a gain factor (μ) of 43 with 1700Ω plate resistance. Commonly used in phono / preamp applications. Same as 5842.

APPLICATIONS

Voltage amplifierHeadphone outputPhono stage

Generic triode phono / preamp stage

• Hi-Fi stereo• Headphone amp

VS 5842

μ 0%Rp +0%Pd 0%Full comparison →

HISTORY

Introduced1956ManufacturerWestern Electric

Golden Age