What is the 8417 vacuum tube?

The 8417 is a pentode vacuum tube designed for power (pp) applications. High-power beam tetrode..

What are the key specifications of the 8417?

Amplification factor μ ≈ 16, transconductance gm ≈ 23 mA/V, plate resistance rp ≈ 16.0 kΩ, max plate voltage 660 V, max plate dissipation 35 W, heater 6.3 V / 1.6 A.

Is the 8417 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 8417 as Sought-after 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 8417 sound like?

High-power beam tetrode.. 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.

8417 Pentode Vacuum Tube

Power pentode delivering up to 35W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 1.6 AOctalGE 1962

Plate dissipation: 35W
Max plate voltage: 660V
Transconductance: 23mA/V

8417

Characteristics

Datasheet values, once each. Every value cites its sheet.

HeaterIndirectly heated

Specifications of 8417 — Heater
Heater voltageVh	6.3 V
Heater currentIh	1.6 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 8417 — Limiting values
Plate voltageVa max	660 V
Plate dissipationPa max	35 W

Mechanical

Specifications of 8417 — Mechanical
Base	Octal
Rarity	Sought-after
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 8417 — Small signal
Transconductance	23 mA/V
Plate resistance	16 kΩ
Amplification factor	16

Capacitances

Specifications of 8417 — Capacitances
Input	22 pF
Grid–plate	0.9 pF
Output	9 pF

Charactereditorial reading, not a measurement

Specifications of 8417 — Character
Gain	16%
Power	88%
Drive	84%
Linearity	92%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Typical operation

Conditions published by the manufacturers, one row per condition. Nothing is computed.

Typical operation
Setup	B+	Vg1 / Rk	Ia	Pout	THD	Source
Class AB1, push-pullultra-linear · fixed bias · values for two tubes	445 V	-25 V	146 mA	70 W	2.5%	OCR, to be checked SYLVANIA ELECTRIC PRODUCTS INC. · 1965 · p. 1 · transcript

Using this tube

Applications

Power output

Generic pentode power (pp) stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Sylvania 8417 datasheetActive model : Koren pentode

Manufacturer datasheets

2 manufacturer datasheets cross-checked for 84172 verified

8417 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Sylvania 8417 datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The 8417 is a indirectly-heated pentode from GE, introduced around 1962. It provides a gain factor (μ) of 16 with 16.0kΩ plate resistance. Commonly used in power (pp) applications. High-power beam tetrode.

History

Introduced: 1962
Manufacturer: GE
Era: Late Production

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