What is the EC86 vacuum tube?

The EC86 is a triode vacuum tube designed for uhf / preamp applications. UHF frame-grid..

What is a EC86 substitute or equivalent?

Direct equivalents to the EC86 include 6CM4. 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 EC86?

Amplification factor μ ≈ 68, transconductance gm ≈ 14 mA/V, plate resistance rp ≈ 5.5 kΩ, max plate voltage 220 V, max plate dissipation 2.2 W, heater 6.3 V / 0.2 A.

Is the EC86 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EC86 as Moderate 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 EC86 sound like?

UHF frame-grid.. 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.

EC86 Triode Vacuum Tube

Also known as 6CM4

Medium-gain triode for driver and line stage applications

TriodeHeater 6.3 V · 0.2 A9-pin NovalSiemens 1960

Plate dissipation: 2.2W
Max plate voltage: 220V
Amplification factor: 68
Transconductance: 14mA/V
Plate resistance: 5.5kΩ

EC86

Characteristics

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

HeaterIndirectly heated

Specifications of EC86 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.2 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EC86 — Limiting values
Plate voltageVa max	220 V
Plate dissipationPa max	2.2 W

Mechanical

Specifications of EC86 — Mechanical
Base	9-pin Noval
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EC86 — Small signal
Transconductance	14 mA/V
Plate resistance	5.5 kΩ
Amplification factor	68

Capacitances

Specifications of EC86 — Capacitances
Grid–cathode	3.6 pF
Grid–plate	2 pF
Plate–cathode	0.2 pF

Charactereditorial reading, not a measurement

Specifications of EC86 — Character
Gain	68%
Power	6%
Drive	95%
Linearity	66%

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

Typical operation

Canonical operating pointSPICE model2 availableModel

B+: 175 V
Load: 5.6 kΩ
Va: 105 V
Ia: 11.51 mA
Vg: -0.5 V
Pd: 1.21 W
Gain: 31.3 dB

At Q: Ayumi Nakabayashi · 2 engines
μ: 72.6
gm: 14.72 mA/V
rp: 4.9 kΩ

Design a stage →

Using this tube

Applications

Voltage amplifier
High-gain preamp

Generic triode uhf / preamp stage

Hi-Fi stereoHeadphone ampStudio/recording

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Philips EC86 datasheet — single UHF triode; corrected sections=1Active model : Ayumi Nakabayashi · 2 engines

Manufacturer datasheets

4 manufacturer datasheets cross-checked for EC864 verified

EC86 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Philips EC86 datasheet — single UHF triode; corrected sections=1
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Ayumi Nakabayashi · 2 engines

Context

The EC86 is a indirectly-heated triode from Siemens, introduced around 1960. It provides a gain factor (μ) of 68 with 5500Ω plate resistance. Commonly used in uhf / preamp applications. UHF frame-grid.

History

Introduced: 1960
Manufacturer: Siemens
Era: Late Production

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