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.

EF80 Pentode Vacuum Tube

Also known as 6BX6

Small-signal pentode for low-noise voltage amplification

PentodeHeater 6.3 V · 0.3 A9-pin NovalPhilips 1955

Plate dissipation: 2.5W
Max plate voltage: 300V
Amplification factor: 50
Transconductance: 7.4mA/V
Plate resistance: 500kΩ

EF80

Characteristics

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

HeaterIndirectly heated

Specifications of EF80 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EF80 — Limiting values
Plate voltageVa max	300 V
Screen voltageVg2 max	300 V
Plate dissipationPa max	2.5 W
Screen dissipationPg2 max	0.7 W
Cathode currentIk max	15 mA
Grid resistorRg1 max	1 MΩ
Peak plate voltageVao	550 V
Heater–cathode voltageVhk max	150 V

Mechanical

Specifications of EF80 — Mechanical
Base	9-pin Noval
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EF80 — Small signal
Transconductance	7.4 mA/V
Plate resistance	500 kΩ
Amplification factor	50

Capacitances

Specifications of EF80 — Capacitances
Input	7.5 pF
Grid–plate	0.007 pF
Output	3.3 pF

Charactereditorial reading, not a measurement

Specifications of EF80 — Character
Gain	50%
Power	6%
Drive	0%
Linearity	75%

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

Using this tube

Applications

Voltage amplifier

Generic pentode rf / preamp stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : audit-eu_b (CLEAN — matches canonical datasheet)Active model : Koren pentode

Manufacturer datasheets

8 manufacturer datasheets cross-checked for EF808 verified

EF80 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: audit-eu_b (CLEAN — matches canonical datasheet)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

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.

History

Introduced: 1955
Manufacturer: Philips
Era: Golden Age

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