What is the ECL84-T vacuum tube?

The ECL84-T (ECL84 (Triode)) is a triode vacuum tube designed for preamp applications. Triode section..

What is a ECL84-T substitute or equivalent?

Direct equivalents to the ECL84-T include 6DX8. 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 ECL84-T?

Amplification factor μ ≈ 65, transconductance gm ≈ 4 mA/V, plate resistance rp ≈ 16.3 kΩ, max plate voltage 250 V, max plate dissipation 1 W, heater 6.3 V / 0.72 A.

Is the ECL84-T still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the ECL84-T 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 ECL84-T sound like?

Triode section.. 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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ECL84-T ECL84 (Triode) Triode Vacuum Tube

Triode6.3V / 0.72A9-pin NovalSPICE

SourcePCL84/ECL84 datasheet (DIYaudio thread)Reviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for voltage amplification applications

Datasheet ↗SPICE

ECL84 (Triode) — Philips — triode vacuum tube — (1960)

16.3kΩ

4.0mA/V

3.9pF

2.7pF

2.30pF

GAIN65%

POWER3%

DRIVE84%

LINEARITY68%

SPECIFICATIONS

Heater6.3 V · 0.72 A

Max Plate Voltage250 V

Pa max1 W

Gain Factor65

gm4 mA/V

rp16.3 kΩ

Inter-electrode capacitances

Cgk3.9 pF

Cgp2.7 pF

Cpk2.3 pF

Pinout9-pin Noval

Era1960

RarityCommon

HEATER6.3V / 0.72A

MAX PLATE250V / 1W

BASEnoval

Source datasheets

3 manufacturer datasheets cross-checked for ECL84 (Triode)

3 verified

TYPICAL OPERATING POINT

Va135V

Ia0.8mA

Vg-1.5V

Pd0.11W

RL33kΩ

Av32.4dB

EXECUTIVE SUMMARY

The ECL84-T is a indirectly-heated triode from Philips, introduced around 1960. It provides a gain factor (μ) of 65 with 16.3kΩ plate resistance. Commonly used in preamp applications. Triode section.

APPLICATIONS

Voltage amplifierHigh-gain preamp

Generic triode preamp stage

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

HISTORY

Introduced1960ManufacturerPhilips

Late Production

ECL84-T Datasheet

Local mirror · PDF

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METRIX TESTER

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