What is the 3A5 vacuum tube?

The 3A5 is a triode vacuum tube designed for portable power applications. Battery power tube..

What is a 3A5 substitute or equivalent?

Direct equivalents to the 3A5 include DL94 equiv. 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 3A5?

Amplification factor μ ≈ 15, transconductance gm ≈ 1.8 mA/V, plate resistance rp ≈ 8.3 kΩ, max plate voltage 135 V, max plate dissipation 0.5 W, heater 1.4 V / 0.22 A.

Is the 3A5 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 3A5 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 3A5 sound like?

Battery power tube.. 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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3A5 Triode Vacuum Tube

Dual triode1.4V / 0.22A7-pin MiniatureSPICE

Sourcer-type.org 3A5 / amplifiedparts 3A5/DCC90Reviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

8.3kΩ

1.8mA/V

0.9pF

3.2pF

1.00pF

GAIN15%

POWER1%

DRIVE92%

LINEARITY93%

SPECIFICATIONS

Heater1.4 V · 0.22 A

Max Plate Voltage135 V

Pa max0.5 W

Gain Factor15

gm1.8 mA/V

rp8.3 kΩ

Inter-electrode capacitances

Cgk0.9 pF

Cgp3.2 pF

Cpk1 pF

Pinout7-pin Miniature

Era1950

RarityModerate

HEATER1.4V / 0.22A

MAX PLATE135V / 0.5W

BASEminiature-7

SECTIONS2 (dual)

Source datasheets

2 manufacturer datasheets cross-checked for 3A5

2 verified

TYPICAL OPERATING POINT

Va81V

Ia3.95mA

Vg-3V

Pd0.32W

RL5kΩ

Av17.2dB

EXECUTIVE SUMMARY

The 3A5 is a dual directly-heated triode from RCA, introduced around 1950. It provides a gain factor (μ) of 15 with 8300Ω plate resistance. Commonly used in portable power applications. Battery power tube.

APPLICATIONS

Line stagePhase splitter

Generic triode portable power stage

• Hi-Fi stereo

HISTORY

Introduced1950ManufacturerRCA

Golden Age

3A5 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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