What is the 12SQ7 vacuum tube?

The 12SQ7 is a triode vacuum tube designed for preamp applications. 12V version of 6SQ7..

What is a 12SQ7 substitute or equivalent?

Direct equivalents to the 12SQ7 include 6SQ7. 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 12SQ7?

Amplification factor μ ≈ 100, transconductance gm ≈ 1.1 mA/V, plate resistance rp ≈ 91.0 kΩ, max plate voltage 300 V, max plate dissipation 1 W, heater 12.6 V / 0.15 A.

Is the 12SQ7 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 12SQ7 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 12SQ7 sound like?

12V version of 6SQ7.. 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

←12SQ7

← 12SJ7 1614 →Compare → 6SQ7

12SQ7 Triode Vacuum Tube

Triode12.6V / 0.15AOctalSPICE

Sourceamplifiedparts 6SQ7 (12SQ7 = same characteristics)Reviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

High-gain dual triode — the standard for guitar and hi-fi preamps

Datasheet ↗SPICE

12SQ7 — RCA — triode vacuum tube — (1938)

100

91.0kΩ

1.1mA/V

3.2pF

1.6pF

3.00pF

GAIN100%

POWER3%

DRIVE9%

LINEARITY50%

SPECIFICATIONS

Heater12.6 V · 0.15 A

Max Plate Voltage300 V

Pa max1 W

Gain Factor100

gm1.1 mA/V

rp91.0 kΩ

Inter-electrode capacitances

Cgk3.2 pF

Cgp1.6 pF

Cpk3 pF

PinoutOctal

Era1938

RarityCommon

HEATER12.6V / 0.15A

MAX PLATE300V / 1W

BASEoctal

Source datasheets

1 manufacturer datasheets cross-checked for 12SQ7

1 verified

TYPICAL OPERATING POINT

Va150V

Ia0.84mA

Vg-1V

Pd0.13W

RL182kΩ

Av36.7dB

EXECUTIVE SUMMARY

The 12SQ7 is a indirectly-heated triode from RCA, introduced around 1938. It provides a gain factor (μ) of 100 with 91.0kΩ plate resistance. Commonly used in preamp applications. 12V version of 6SQ7.

APPLICATIONS

Voltage amplifierHigh-gain preamp

Generic triode preamp stage

• Hi-Fi stereo• Headphone amp• Studio/recording

VS 6SQ7

μ 0%Rp +0%Pd +100%Full comparison →

HISTORY

Introduced1938ManufacturerRCA

Pre-War