What is the 46 vacuum tube?

The 46 is a triode vacuum tube designed for power (set) applications. Dual-grid power tube. 45 cousin in triode mode..

What is a 46 substitute or equivalent?

Direct equivalents to the 46 include None standard. 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 46?

Amplification factor μ ≈ 6, transconductance gm ≈ 2.35 mA/V, plate resistance rp ≈ 2.4 kΩ, max plate voltage 400 V, max plate dissipation 10 W, heater 2.5 V / 1.75 A.

Is the 46 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 46 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 46 sound like?

Dual-grid power tube. 45 cousin in triode mode.. 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

←46

← 45B-EmissionLabs 47 →Compare…

46 Triode Vacuum Tube

Triode2.5V / 1.75AUX-5SPICE

SourceRCA·SylvaniaReviewed2026-05-29StatusDataModelCalcModelAyumi NakabayashiPDF

Power triode delivering 10W for push-pull and SET designs

Datasheet ↗SPICE

46 — RCA·Sylvania — triode vacuum tube — (1931)

2.4kΩ

2.4mA/V

7.0pF

7.5pF

4.50pF

GAIN6%

POWER25%

DRIVE98%

LINEARITY95%

SPECIFICATIONS

Heater2.5 V · 1.75 A

Max Plate Voltage400 V

Pa max10 W

Gain Factor6

gm2.35 mA/V

rp2.4 kΩ

Inter-electrode capacitances

Cgk7 pF

Cgp7.5 pF

Cpk4.5 pF

PinoutUX-5

Era1931

RaritySought-after

HEATER2.5V / 1.75A

MAX PLATE400V / 10W

BASEux5

Source datasheets

4 manufacturer datasheets cross-checked for 46

4 verified

EXECUTIVE SUMMARY

The 46 is a directly-heated triode from RCA·Sylvania, introduced around 1931. It provides a gain factor (μ) of 6 with 2380Ω plate resistance. Commonly used in power (set) applications. Dual-grid power tube. 45 cousin in triode mode.

APPLICATIONS

SET outputPush-pull output

Generic triode power (set) stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1931ManufacturerRCA·Sylvania

Pre-War

46 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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