What is the ECL85 vacuum tube?

The ECL85 is a pentode vacuum tube designed for power applications.

What is a ECL85 substitute or equivalent?

Direct equivalents to the ECL85 include 6GV8. 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.

Is the ECL85 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the ECL85 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 ECL85 sound like?

Sonic character depends 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.

ECL85 Pentode Vacuum Tube

Also known as 6GV8

Triode + Pentode9-pin Noval2 sectionsPhilips 1960

Triode · Plate dissipation: 0.5W
Triode · Amplification factor: 50
Pentode · Plate dissipation: 7W
Pentode · Max screen voltage: 250V

ECL85

Characteristics

Datasheet values, once each. Every value cites its sheet.

Mechanical

Specifications of ECL85 — Mechanical
Base	9-pin Noval
Rarity	Common
Pinout

TriodeTriode

HeaterIndirectly heated

Specifications of ECL85-T — Triode — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.9 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of ECL85-T — Triode — Limiting values
Plate voltageVa max	250 V
Screen voltageVg2 max	250 V
Plate dissipationPa max	0.5 W
Screen dissipationPg2 max	1.5 W
Cathode currentIk max	75 mA
Grid resistorRg1 max	1 MΩ
Peak plate voltageVao	550 V
Heater–cathode voltageVhk max	100 V

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of ECL85-T — Triode — Small signal
Transconductance	5.5 mA/V
Plate resistance	9 kΩ
Amplification factor	50

Capacitances

Specifications of ECL85-T — Triode — Capacitances
Grid–cathode	2.5 pF
Grid–plate	1.5 pF
Plate–cathode	0.5 pF

Charactereditorial reading, not a measurement

Specifications of ECL85-T — Triode — Character
Gain	50%
Power	1%
Drive	91%
Linearity	75%

PentodePentode

HeaterIndirectly heated

Specifications of ECL85-P — Pentode — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.875 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of ECL85-P — Pentode — Limiting values
Plate voltageVa max	250 V
Screen voltageVg2 max	250 V
Plate dissipationPa max	7 W
Screen dissipationPg2 max	1.5 W
Cathode currentIk max	75 mA
Grid resistorRg1 max	1 MΩ

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of ECL85-P — Pentode — Small signal
Transconductance	7.5 mA/V
Plate resistance	25 kΩ

Capacitances

Specifications of ECL85-P — Pentode — Capacitances
Input	12 pF
Grid–plate	0.6 pF
Output	8 pF

Charactereditorial reading, not a measurement

Specifications of ECL85-P — Pentode — Character
Gain	0%
Power	18%
Drive	75%
Linearity	75%

datasheet cited · model or editorial reading · catalogue value, no citation attached yet · nothing invented

Typical operation

Canonical operating pointModel

B+: 225 V
Load: 18 kΩ
Va: 135 V
Ia: 2.79 mA
Vg: -2 V
Pd: 0.38 W
Gain: 29.6 dB

At Q: Norman Koren
μ: 51
gm: 3.62 mA/V
rp: 14.1 kΩ

Design a stage →

Using this tube

Applications

Phase splitter

Generic pentode power stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : r-type.org ECL85/6GV8

Manufacturer datasheets

Triode

4 manufacturer datasheets cross-checked for ECL85 — Triode4 verified

Pentode

4 manufacturer datasheets cross-checked for ECL85 — Pentode4 verified

ECL85 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: r-type.org ECL85/6GV8
Reviewed: 2026-05-29
Status: DataModelCalc
Model: SPICE model

Context

The ECL85-T is a indirectly-heated triode from Philips, introduced around 1960. It provides a gain factor (μ) of 50 with 9000Ω plate resistance. Commonly used in preamp applications. Triode section. The ECL85-P is a indirectly-heated pentode from Philips, introduced around 1960. Commonly used in power applications. Pentode section.

History

Introduced: 1960
Manufacturer: Philips
Era: Late Production

METRIX TESTER

Characteristics

Mechanical

TriodeTriode

HeaterIndirectly heated

Limiting valuesDatasheet maximum ratings — not to be exceeded

Small signalDatasheet parameters at the reference operating point — not limits

Capacitances

Charactereditorial reading, not a measurement?

PentodePentode

HeaterIndirectly heated

Limiting valuesDatasheet maximum ratings — not to be exceeded

Small signalDatasheet parameters at the reference operating point — not limits

Capacitances

Charactereditorial reading, not a measurement?

Typical operation

Using this tube

Applications

Replace or compare

Versus 12SJ7

Similar tubes

Sources

Manufacturer datasheets

SPICE models

Context

History

Test this tube on a Metrix

Charactereditorial reading, not a measurement

Charactereditorial reading, not a measurement