What is the PL504 vacuum tube?

The PL504 is a pentode vacuum tube designed for power applications. Enhanced PL500..

What are the key specifications of the PL504?

Transconductance gm ≈ 14 mA/V, max plate voltage 250 V, max plate dissipation 16 W, heater 27 V / 0.3 A.

Is the PL504 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the PL504 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 PL504 sound like?

Enhanced PL500.. 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.

PL504 Pentode Vacuum Tube

Power pentode delivering up to 16W in pentode, UL, or triode mode

PentodeHeater 27 V · 0.3 AMagnovalPhilips 1963

Plate dissipation: 16W
Max plate voltage: 250V
Max screen voltage: 250V
Max cathode current: 250mA
Transconductance: 14mA/V

PL504

Characteristics

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

HeaterIndirectly heated

Specifications of PL504 — Heater
Heater voltageVh	27 V
Heater currentIh	0.3 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of PL504 — Limiting values
Plate voltageVa max	250 V
Screen voltageVg2 max	250 V
Plate dissipationPa max	16 W
Cathode currentIk max	250 mA
Grid resistorRg1 max	500 kΩ
Peak plate voltageVao	550 V

Mechanical

Specifications of PL504 — Mechanical
Base	Magnoval
Rarity	Common
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of PL504 — Small signal
Transconductance	14 mA/V

Capacitances

Specifications of PL504 — Capacitances
Input	15 pF
Grid–plate	1.75 pF
Output	7.5 pF

Charactereditorial reading, not a measurement

Specifications of PL504 — Character
Gain	0%
Power	40%
Drive	50%
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 : PL504 datasheet (beam power tube)Active model : Koren pentode

Manufacturer datasheets

2 manufacturer datasheets cross-checked for PL5042 verified

PL504 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: PL504 datasheet (beam power tube)
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Koren pentode

Context

The PL504 is a indirectly-heated pentode from Philips, introduced around 1963. Commonly used in power applications. Enhanced PL500.

History

Introduced: 1963
Manufacturer: Philips
Era: Late Production

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