What is the 12AU7 vacuum tube?

The 12AU7 (12AU7 / ECC82) is a triode vacuum tube designed for line / headphone applications. Open, transparent, neutral..

What is a 12AU7 substitute or equivalent?

Direct equivalents to the 12AU7 include ECC82, 5814A. 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 12AU7?

Amplification factor μ ≈ 17, transconductance gm ≈ 2.2 mA/V, plate resistance rp ≈ 7.7 kΩ, max plate voltage 300 V, max plate dissipation 2.75 W, heater 12.6 V / 0.15 A.

Is the 12AU7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 12AU7 as Common 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 12AU7 sound like?

Open, transparent, neutral.. 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

←12AU7

← 12AT7 12AX7 →Compare → ECC82

12AU7 12AU7 / ECC82 Triode Vacuum Tube

Dual triode12.6V / 0.15A9-pin NovalSPICE

SourceRCA·Amperex datasheetReviewed2026-05-29StatusDataModelCalcModelKoren v1PDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

12AU7 / ECC82 — RCA·Amperex — triode vacuum tube — (1946)

7.7kΩ

2.2mA/V

1.7pF

1.5pF

0.50pF

GAIN17%

POWER7%

DRIVE92%

LINEARITY92%

SPECIFICATIONS

Heater12.6 V · 0.15 A

Max Plate Voltage300 V

Pa max2.75 W

Gain Factor17

gm2.2 mA/V

rp7.7 kΩ

Inter-electrode capacitances

Cgk1.7 pF

Cgp1.5 pF

Cpk0.5 pF

Pinout9-pin Noval

Era1946

RarityCommon

HEATER12.6V / 0.15A

MAX PLATE300V / 2.75W

BASEnoval

SECTIONS2 (dual)

Source datasheets

2 manufacturer datasheets cross-checked for 12AU7 / ECC82

2 verified

TYPICAL OPERATING POINT

SPICE model(2 available)6 .subckt available ↓

Va180V

Ia5.97mA

Vg-6.62V

Pd1.07W

RL12kΩ

Av21.5dB

EXECUTIVE SUMMARY

The 12AU7 (ECC82) is a low-mu (mu ~17) dual triode with the lowest gain and lowest plate resistance of the 12A_7 family. Its strong suit is current delivery and linearity rather than voltage gain, making it the preferred tube for cathode followers, buffers, headphone amplifiers, and line output stages. The low mu and low plate resistance (~7.7k ohms) give it excellent load-driving capability and a relaxed, open sonic character. It is also commonly used as a phase inverter in push-pull power amplifiers where a 12AX7 would have excessive gain.

APPLICATIONS

Line stagePhase splitter

McIntosh C22 line stageMarantz 8B driver

• Guitar amp• Headphone amp

VS ECC82

μ 0%Rp +0%Pd 0%Full comparison →

HISTORY

Introduced1946ManufacturerRCA·Amperex

Golden Age

12AU7 Datasheet

Local mirror · PDF

↗

METRIX TESTER

Test this tube on a Metrix

CLASSIC CIRCUITS

Headphone Amp

12AU7 Preamp Stage

N/A

Typical 12AU7 voltage amplifier stage for headphone buffer or line-level preamp. Moderate gain with low output impedance.

SEVb 250V · Vg -8.5V · RL 100kΩ

RCA 12AU7 Datasheet

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