What is the 829B vacuum tube?

The 829B is a tetrode vacuum tube designed for transmitting applications. Push-pull beam in one envelope..

What is a 829B substitute or equivalent?

Direct equivalents to the 829B include 3E29. 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 829B?

Amplification factor μ ≈ 9, transconductance gm ≈ 8.5 mA/V, max plate voltage 750 V, max plate dissipation 40 W, heater 6.3 V / 2.25 A.

Is the 829B still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 829B as Moderate 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 829B sound like?

Push-pull beam in one envelope.. 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.

829B Tetrode Vacuum Tube

Also known as 3E29

Beam power tetrode rated at 40W for high-power output stages

TetrodeHeater 6.3 V · 2.25 ASpecialRCA 1942

Plate dissipation: 40W
Max plate voltage: 750V
Transconductance: 8.5mA/V

829B

Characteristics

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

HeaterIndirectly heated

Specifications of 829B — Heater
Heater voltageVh	6.3 V
Heater currentIh	2.25 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 829B — Limiting values
Plate voltageVa max	750 V
Plate dissipationPa max	40 W

Mechanical

Specifications of 829B — Mechanical
Base	Special
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 829B — Small signal
Transconductance	8.5 mA/V
Amplification factor	9

Capacitances

Specifications of 829B — Capacitances
Input	14.5 pF
Grid–plate	0.12 pF
Output	7 pF

Charactereditorial reading, not a measurement

Specifications of 829B — Character
Gain	9%
Power	100%
Drive	50%
Linearity	95%

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	Va	Vg2	Vg1 / Rk	Ia	Ig2	Load	Source
Class AB1, push-pullpentode connection · fixed bias	600 V	200 V	-18 V	40 mA	6 mA	13.8 kΩ a-a	OCR, to be checked RCA · 1963 · p. 2 · transcript

Using this tube

Applications

High-power output

Generic tetrode transmitting stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Frank/pocnet 829B · amplifiedpartsActive model : Koren pentode

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 829B3 verified

829B DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Frank/pocnet 829B · amplifiedparts
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The 829B is a indirectly-heated beam tetrode from RCA, introduced around 1942. Commonly used in transmitting applications. Push-pull beam in one envelope.

History

Introduced: 1942
Manufacturer: RCA
Era: Pre-War

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