What is the ECF80-P vacuum tube?

The ECF80-P (ECF80 (Pentode)) is a pentode vacuum tube designed for preamp applications. Pentode section..

What is a ECF80-P substitute or equivalent?

Direct equivalents to the ECF80-P include 6BL8. 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 ECF80-P?

Amplification factor μ ≈ 47, transconductance gm ≈ 6.2 mA/V, plate resistance rp ≈ 400.0 kΩ, max plate voltage 250 V, max plate dissipation 1.7 W, heater 6.3 V / 0.43 A.

Is the ECF80-P still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the ECF80-P 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 ECF80-P sound like?

Pentode 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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ECF80-P ECF80 (Pentode) Pentode Vacuum Tube

Pentode6.3V / 0.43A9-pin NovalSPICE

SourcePhilips ECF80 datasheetReviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE

ECF80 (Pentode) — Philips — pentode vacuum tube — (1955)

400.0kΩ

6.2mA/V

5.2pF

0.0pF

3.40pF

GAIN47%

POWER4%

DRIVE0%

LINEARITY77%

SPECIFICATIONS

Heater6.3 V · 0.43 A

Max Plate Voltage250 V

Pa max1.7 W

Gain Factor47

gm6.2 mA/V

rp400.0 kΩ

Inter-electrode capacitances

Cgk5.2 pF

Cgp0.025 pF

Cpk3.4 pF

Pinout9-pin Noval

Era1955

RarityCommon

HEATER6.3V / 0.43A

MAX PLATE250V / 1.7W

BASEnoval

Source datasheets

6 manufacturer datasheets cross-checked for ECF80 (Pentode)

6 verified

EXECUTIVE SUMMARY

The ECF80-P is a indirectly-heated pentode from Philips, introduced around 1955. It provides a gain factor (μ) of 47 with 400.0kΩ plate resistance. Commonly used in preamp applications. Pentode section.

APPLICATIONS

Voltage amplifier

Generic pentode preamp stage

HISTORY

Introduced1955ManufacturerPhilips

Golden Age

ECF80-P Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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