What is the EF80 vacuum tube?

The EF80 is a pentode vacuum tube designed for rf / preamp applications. VHF amplifier..

What is a EF80 substitute or equivalent?

Direct equivalents to the EF80 include 6BX6. 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 EF80?

Amplification factor μ ≈ 50, transconductance gm ≈ 7.4 mA/V, plate resistance rp ≈ 500.0 kΩ, max plate voltage 300 V, max plate dissipation 2.5 W, heater 6.3 V / 0.3 A.

Is the EF80 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EF80 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 EF80 sound like?

VHF amplifier.. 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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EF80 Pentode Vacuum Tube

Pentode6.3V / 0.3A9-pin NovalSPICE

Sourceaudit-eu_b (CLEAN — matches canonical datasheet)Reviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗SPICE

EF80 — Philips — pentode vacuum tube — (1955)

500.0kΩ

7.4mA/V

7.5pF

0.0pF

3.30pF

GAIN50%

POWER6%

DRIVE0%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.3 A

Max Plate Voltage300 V

Pa max2.5 W

Gain Factor50

gm7.4 mA/V

rp500.0 kΩ

Inter-electrode capacitances

Cgk7.5 pF

Cgp0.007 pF

Cpk3.3 pF

Pinout9-pin Noval

Era1955

RarityCommon

HEATER6.3V / 0.3A

MAX PLATE300V / 2.5W

BASEnoval

Source datasheets

8 manufacturer datasheets cross-checked for EF80

8 verified

EXECUTIVE SUMMARY

The EF80 is a indirectly-heated pentode from Philips, introduced around 1955. It provides a gain factor (μ) of 50 with 500.0kΩ plate resistance. Commonly used in rf / preamp applications. VHF amplifier.

APPLICATIONS

Voltage amplifier

Generic pentode rf / preamp stage

HISTORY

Introduced1955ManufacturerPhilips

Golden Age

EF80 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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