What is the 6LQ6 vacuum tube?

The 6LQ6 is a tetrode vacuum tube designed for power applications. High-current compactron..

What is a 6LQ6 substitute or equivalent?

Direct equivalents to the 6LQ6 include 6JE6. 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 6LQ6?

Amplification factor μ ≈ 3, transconductance gm ≈ 9.6 mA/V, plate resistance rp ≈ 5.8 kΩ, max plate voltage 990 V, max plate dissipation 30 W, heater 6.3 V / 2.5 A.

Is the 6LQ6 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6LQ6 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 6LQ6 sound like?

High-current compactron.. 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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6LQ6 Tetrode Vacuum Tube

Tetrode6.3V / 2.5A12-pin CompactronSPICE

Sourceamplifiedparts 6JE6C/6LQ6 beam powerReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Beam power tetrode rated at 30W for high-power output stages

Datasheet ↗SPICE

6LQ6 — RCA — tetrode vacuum tube — (1962)

5.8kΩ

9.6mA/V

22.0pF

0.6pF

11.00pF

GAIN3%

POWER75%

DRIVE94%

LINEARITY95%

SPECIFICATIONS

Heater6.3 V · 2.5 A

Max Plate Voltage990 V

Pa max30 W

Gain Factor3

gm9.6 mA/V

rp5.8 kΩ

Inter-electrode capacitances

Cgk22 pF

Cgp0.56 pF

Cpk11 pF

Pinout12-pin Compactron

Era1962

RarityCommon

HEATER6.3V / 2.5A

MAX PLATE990V / 30W

BASEcompactron-12

Source datasheets

2 manufacturer datasheets cross-checked for 6LQ6

2 verified

Triode-connectedGeneral Electric1973 (3-73; curves FEBRUARY 4, 1970)

Specs when the screen grid (g2) is tied to the anode — the tube acts as a triode.

According to General Electric (GE Tubes) (1973 (3-73; curves FEBRUARY 4, 1970)): « Triode Connection »

EXECUTIVE SUMMARY

The 6LQ6 is a indirectly-heated beam tetrode from RCA, introduced around 1962. It provides a gain factor (μ) of 3 with 5800Ω plate resistance. Commonly used in power applications. High-current compactron.

APPLICATIONS

High-power output

Generic tetrode power stage

• PA/public address

HISTORY

Introduced1962ManufacturerRCA

Late Production

6LQ6 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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