What is the 12AT7 vacuum tube?

The 12AT7 (12AT7 / ECC81) is a triode vacuum tube designed for driver applications. Detailed, articulate..

What is a 12AT7 substitute or equivalent?

Direct equivalents to the 12AT7 include ECC81, 6201. 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 12AT7?

Amplification factor μ ≈ 60, transconductance gm ≈ 5.5 mA/V, plate resistance rp ≈ 10.9 kΩ, max plate voltage 300 V, max plate dissipation 2.5 W, heater 12.6 V / 0.15 A.

Is the 12AT7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 12AT7 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 12AT7 sound like?

Detailed, articulate.. 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

←12AT7

← 10Y 12AU7 →Compare → ECC81

12AT7 12AT7 / ECC81 Triode Vacuum Tube

Dual triode12.6V / 0.15A9-pin NovalSPICE

SourceMullard·GE datasheetReviewed2026-05-29StatusDataModelCalcModelKoren v1PDF

Medium-gain triode for voltage amplification applications

Datasheet ↗SPICE

12AT7 / ECC81 — Mullard·GE — triode vacuum tube — (1947)

10.9kΩ

5.5mA/V

2.2pF

1.5pF

0.50pF

GAIN60%

POWER6%

DRIVE89%

LINEARITY70%

SPECIFICATIONS

Heater12.6 V · 0.15 A

Max Plate Voltage300 V

Pa max2.5 W

Gain Factor60

gm5.5 mA/V

rp10.9 kΩ

Inter-electrode capacitances

Cgk2.2 pF

Cgp1.5 pF

Cpk0.5 pF

Pinout9-pin Noval

Era1947

RarityCommon

HEATER12.6V / 0.15A

MAX PLATE300V / 2.5W

BASEnoval

SECTIONS2 (dual)

Source datasheets

6 manufacturer datasheets cross-checked for 12AT7 / ECC81

6 verified

TYPICAL OPERATING POINT

SPICE model(3 available)6 .subckt available ↓

Va180V

Ia3.73mA

Vg-2.17V

Pd0.67W

RL10kΩ

Av28dB

EXECUTIVE SUMMARY

The 12AT7 (ECC81) is a medium-mu (mu ~60) dual triode designed for VHF applications, with lower plate resistance (~11k ohms) and higher transconductance than the 12AX7. In audio it serves as a driver tube, phase inverter, or anywhere moderate gain with better current delivery is needed than a 12AX7 can provide. Its lower plate resistance makes it superior for driving capacitive loads and long interstage connections. The 12AT7 is also the standard reverb driver and effects loop tube in guitar amplifiers, where its current capability matters more than raw voltage gain.

APPLICATIONS

High-gain preampPhase splitter

Marshall JCM800 PIFender reverb driver

• Guitar amp• Headphone amp• Studio/recording

VS ECC81

μ 0%Rp -1%Pd 0%Full comparison →

HISTORY

Introduced1947ManufacturerMullard·GE

Golden Age

12AT7 Datasheet

Local mirror · PDF

↗

METRIX TESTER

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CLASSIC CIRCUITS

Preamp Stage

12AT7 Driver Stage

N/A

12AT7 as phase inverter or driver stage. Medium-mu triode with higher current capability than 12AX7. Common in Fender reverb drivers.

SEVb 250V · Vg -2V · RL 47kΩ

Fender Reverb Driver Circuit

SIMILAR TRIODES

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12AT7 12AT7 / ECC81 Triode Vacuum Tube

Source datasheets

Test this tube on a Metrix

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