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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

ECL85 Pentode Vacuum Tube

Triode + Pentode9-pin Noval2 sectionsAlso known as6GV8

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

ECL85

In brief

TriodeTriode

μ: 50
gm: 5.5 mA/V
rp: 9 kΩ
Pa: 0.5 W

PentodePentode

gm: 7.5 mA/V
rp: 25 kΩ
Pa: 7 W

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.

Limits

Specifications of ECL85-T — Triode
Specification	Value	Source
Heater
Heater voltage	6.3 V	Datasheet
Heater current	0.9 A	Datasheet
LimitsDatasheet maximum ratings — not to be exceeded
Max Plate V	250 V	Datasheet
Pa max	0.5 W	Datasheet

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

Open the loadline calculator

APPLICATIONS

Phase splitter

Generic pentode power stage

Replace or compare

Sources

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

HISTORY

Introduced: 1960
Manufacturer: Philips
Era: Late Production

METRIX TESTER