What is the 5R4GY vacuum tube?

The 5R4GY is a rectifier vacuum tube designed for rectifier applications. Robust..

What is a 5R4GY substitute or equivalent?

Direct equivalents to the 5R4GY include 5R4WGA. 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.

Is the 5R4GY still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 5R4GY 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 5R4GY sound like?

Robust.. 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.

5R4GY Rectifier Vacuum Tube

Also known as 5R4WGA

Full-wave rectifier for vacuum tube power supply designs

RectifierHeater 5 V · 2 AOctalRCA 1942

Max DC output current: 250mA
Peak inverse voltage: 2800V
Max RMS input per anode: 1000V
Peak anode current: 650mA

5R4GY

Characteristics

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

HeaterDirectly heated

Specifications of 5R4GY — Heater
Heater voltageVh	5 V
Heater currentIh	2 A

Rectifier limitsDatasheet maximum ratings — not to be exceeded

Specifications of 5R4GY — Rectifier limits
Max RMS input voltage per anode	1000 V
Io max (DC output current)	250 mA
Peak inverse voltage (PIV)	2800 V
Peak anode current	650 mA
Max reservoir capacitor	4 µF
Min series resistance per anode	575 Ω

Mechanical

Specifications of 5R4GY — Mechanical
Base	Octal
Rarity	Moderate
Pinout

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

Using this tube

Interactive loadline calculator not available for this tube yet — it needs calibrated Koren or Ayumi parameters.

Applications

Power supply rectification

Generic rectifier rectifier stage

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : cap audit 2026-05-09

Manufacturer datasheets

4 manufacturer datasheets cross-checked for 5R4GY4 verified

5R4GY DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: cap audit 2026-05-09
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The 5R4GY is a full-wave directly-heated rectifier with a high voltage drop (~60-70V under load) and a relatively stiff, slow recovery characteristic. This substantial voltage drop provides significant power supply sag that contributes to a compressed, touch-sensitive dynamic response in guitar amplifiers and a relaxed presentation in hi-fi equipment. The tube was widely used in military equipment and industrial power supplies where the voltage drop was acceptable and the rugged construction was valued. Its high internal resistance effectively functions as built-in power supply impedance, which some designers deliberately exploit as part of the amplifier's voicing.

History

Introduced: 1942
Manufacturer: RCA
Era: Pre-War

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