What is the EL506 vacuum tube?

The EL506 is a pentode vacuum tube designed for power applications. Magnoval power..

What are the key specifications of the EL506?

Transconductance gm ≈ 10.2 mA/V, plate resistance rp ≈ 25.0 kΩ, max plate voltage 550 V, max plate dissipation 19 W, heater 6.3 V / 0.8 A.

Is the EL506 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EL506 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 EL506 sound like?

Magnoval power.. 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.

EL506 Pentode Vacuum Tube

Power pentode delivering up to 19W in pentode, UL, or triode mode

PentodeHeater 6.3 V · 0.8 AMagnovalPhilips 1962

Plate dissipation: 19W
Max plate voltage: 550V
Max screen voltage: 300V
Transconductance: 10.2mA/V

EL506

Characteristics

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

HeaterIndirectly heated

Specifications of EL506 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.8 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of EL506 — Limiting values
Plate voltageVa max	550 V
Screen voltageVg2 max	300 V
Plate dissipationPa max	19 W

Mechanical

Specifications of EL506 — Mechanical
Base	Magnoval
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of EL506 — Small signal
Transconductance	10.2 mA/V
Plate resistance	25 kΩ

Capacitances

Specifications of EL506 — Capacitances
Input	9 pF
Grid–plate	0.4 pF
Output	4 pF

Charactereditorial reading, not a measurement

Specifications of EL506 — Character
Gain	0%
Power	48%
Drive	75%
Linearity	75%

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

Using this tube

Applications

Power output

Generic pentode power stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : EL506 datasheet (beam power, not strict pentode)Active model : Koren pentode

Manufacturer datasheets

1 manufacturer datasheets cross-checked for EL5061 verified

EL506 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: EL506 datasheet (beam power, not strict pentode)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The EL506 is a indirectly-heated pentode from Philips, introduced around 1962. Commonly used in power applications. Magnoval power.

History

Introduced: 1962
Manufacturer: Philips
Era: Late Production

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