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.

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

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829B Tetrode Vacuum Tube

Tetrode6.3V / 2.25ASpecialSPICE

SourceFrank/pocnet 829B · amplifiedpartsReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

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

Datasheet ↗SPICE

829B — RCA — tetrode vacuum tube — (1942)

8.5mA/V

14.5pF

0.1pF

7.00pF

GAIN9%

POWER100%

DRIVE50%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 2.25 A

Max Plate Voltage750 V

Pa max40 W

Gain Factor9

gm8.5 mA/V

rp—

Inter-electrode capacitances

Cgk14.5 pF

Cgp0.12 pF

Cpk7 pF

PinoutSpecial

Era1942

RarityModerate

HEATER6.3V / 2.25A

MAX PLATE750V / 40W

BASEspecial

Source datasheets

3 manufacturer datasheets cross-checked for 829B

3 verified

EXECUTIVE SUMMARY

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

APPLICATIONS

High-power output

Generic tetrode transmitting stage

• PA/public address

HISTORY

Introduced1942ManufacturerRCA

Pre-War

829B Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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