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.

PL36 Pentode Vacuum Tube

Also known as 25E5

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

PentodeHeater 25 V · 0.3 AOctalPhilips 1955

Plate dissipation: 10W
Max plate voltage: 250V
Max screen voltage: 250V
Max cathode current: 200mA
Transconductance: 14mA/V

PL36

Characteristics

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

HeaterIndirectly heated

Specifications of PL36 — Heater
Heater voltageVh	25 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of PL36 — Limiting values
Plate voltageVa max	250 V
Screen voltageVg2 max	250 V
Plate dissipationPa max	10 W
Screen dissipationPg2 max	5 W
Cathode currentIk max	200 mA
Grid resistorRg1 max	500 kΩ
Peak plate voltageVao	550 V

Mechanical

Specifications of PL36 — Mechanical
Base	Octal
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of PL36 — Small signal
Transconductance	14 mA/V
Plate resistance	5 kΩ
Amplification factor	6

Capacitances

Specifications of PL36 — Capacitances
Input	17.5 pF
Grid–plate	1.1 pF
Output	8 pF

Charactereditorial reading, not a measurement

Specifications of PL36 — Character
Gain	6%
Power	25%
Drive	95%
Linearity	95%

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 : audit-eu_b (CLEAN — matches canonical datasheet)Active model : Koren pentode

Manufacturer datasheets

5 manufacturer datasheets cross-checked for PL365 verified

PL36 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 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.

History

Introduced: 1955
Manufacturer: Philips
Era: Golden Age

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