What is the EL506 vacuum tube?

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

What is a EL506 substitute or equivalent?

Direct equivalents to the EL506 include None. 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 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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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EL506 Pentode Vacuum Tube

Pentode6.3V / 0.8AMagnovalSPICE

SourceEL506 datasheet (beam power, not strict pentode)Reviewed2026-05-29StatusDataModelCalcModelKoren pentodePDF

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

Datasheet ↗SPICE

EL506 — Philips — pentode vacuum tube — (1962)

25.0kΩ

10.2mA/V

9.0pF

0.4pF

4.00pF

GAIN0%

POWER48%

DRIVE75%

LINEARITY75%

SPECIFICATIONS

Heater6.3 V · 0.8 A

Max Plate Voltage550 V

Pa max19 W

Gain Factor—

gm10.2 mA/V

rp25.0 kΩ

Inter-electrode capacitances

Cgk9 pF

Cgp0.4 pF

Cpk4 pF

PinoutMagnoval

Era1962

RarityModerate

HEATER6.3V / 0.8A

MAX PLATE550V / 19W

BASEmagnoval

Source datasheets

1 manufacturer datasheets cross-checked for EL506

1 verified

EXECUTIVE SUMMARY

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

APPLICATIONS

Power output

Generic pentode power stage

HISTORY

Introduced1962ManufacturerPhilips

Late Production

EL506 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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