What is the 813 vacuum tube?

The 813 is a pentode vacuum tube designed for transmitting applications. Beam tetrode giant. Deep controlled bass in triode..

What is a 813 substitute or equivalent?

Direct equivalents to the 813 include VT-144. 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 813?

Amplification factor μ ≈ 8, transconductance gm ≈ 3.75 mA/V, max plate voltage 2500 V, max plate dissipation 125 W, heater 10 V / 5 A.

Is the 813 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 813 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 813 sound like?

Beam tetrode giant. Deep controlled bass in triode.. 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.

813 Pentode Vacuum Tube

Also known as VT-144

Power pentode delivering up to 125W in pentode, UL, or triode mode

PentodeHeater 10 V · 5 ASpecialRCA·Amperex 1938

Plate dissipation: 125W
Max plate voltage: 2500V
Transconductance: 3.75mA/V

813

Characteristics

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

HeaterDirectly heated

Specifications of 813 — Heater
Heater voltageVh	10 V
Heater currentIh	5 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 813 — Limiting values
Plate voltageVa max	2500 V
Plate dissipationPa max	125 W

Mechanical

Specifications of 813 — Mechanical
Base	Special
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 813 — Small signal
Transconductance	3.75 mA/V
Amplification factor	8

Capacitances

Specifications of 813 — Capacitances
Input	16.3 pF
Grid–plate	0.25 pF
Output	14 pF

Charactereditorial reading, not a measurement

Specifications of 813 — Character
Gain	8%
Power	100%
Drive	50%
Linearity	95%

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

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

Power output

Generic pentode transmitting stage

PA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : RCA 813 datasheet (beam tetrode classification) · cap audit 2026-05-09

Manufacturer datasheets

2 manufacturer datasheets cross-checked for 8132 verified

813 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: RCA 813 datasheet (beam tetrode classification) · cap audit 2026-05-09
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The 813 is a directly-heated pentode from RCA·Amperex, introduced around 1938. Commonly used in transmitting applications. Beam tetrode giant. Deep controlled bass in triode.

History

Introduced: 1938
Manufacturer: RCA·Amperex
Era: Pre-War

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