What is the PL36 vacuum tube?

The PL36 is a pentode vacuum tube designed for power applications. Series-heater sweep..

What is a PL36 substitute or equivalent?

Direct equivalents to the PL36 include 25E5. 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 PL36?

Amplification factor μ ≈ 6, transconductance gm ≈ 14 mA/V, plate resistance rp ≈ 5.0 kΩ, max plate voltage 250 V, max plate dissipation 10 W, heater 25 V / 0.3 A.

Is the PL36 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the PL36 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 PL36 sound like?

Series-heater sweep.. 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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PL36 Pentode Vacuum Tube

Pentode25V / 0.3AOctalSPICE

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

Power pentode delivering up to 10W in pentode, UL, or triode mode

Datasheet ↗SPICE

PL36 — Philips — pentode vacuum tube — (1955)

5.0kΩ

14.0mA/V

17.5pF

1.1pF

8.00pF

GAIN6%

POWER25%

DRIVE95%

LINEARITY95%

SPECIFICATIONS

Heater25 V · 0.3 A

Max Plate Voltage250 V

Pa max10 W

Gain Factor6

gm14 mA/V

rp5.0 kΩ

Inter-electrode capacitances

Cgk17.5 pF

Cgp1.1 pF

Cpk8 pF

PinoutOctal

Era1955

RarityCommon

HEATER25V / 0.3A

MAX PLATE250V / 10W

BASEoctal

Source datasheets

5 manufacturer datasheets cross-checked for PL36

5 verified

EXECUTIVE SUMMARY

The PL36 is a indirectly-heated pentode from Philips, introduced around 1955. It provides a gain factor (μ) of 6 with 5000Ω plate resistance. Commonly used in power applications. Series-heater sweep.

APPLICATIONS

Power output

Generic pentode power stage

HISTORY

Introduced1955ManufacturerPhilips

Golden Age

PL36 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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