What is the GP-5 vacuum tube?

The GP-5 (GP-5 / ГП-5) is a triode vacuum tube designed for voltage regulator applications. High-voltage shunt regulator. TV / X-ray..

What is a GP-5 substitute or equivalent?

Direct equivalents to the GP-5 include ED500, 6BK4. 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 GP-5?

Amplification factor μ ≈ 2750, transconductance gm ≈ 0.7 mA/V, plate resistance rp ≈ 3900.0 kΩ, max plate voltage 30000 V, max plate dissipation 37.5 W, heater 6.3 V / 0.21 A.

Is the GP-5 still in production?

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

High-voltage shunt regulator. TV / X-ray.. 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.

GP-5 ГП-5 Triode Vacuum Tube

Also known as ED500 · 6BK4

Power triode delivering 37.5W for push-pull and SET designs

TriodeHeater 6.3 V · 0.21 A9-pin MagnovalSvetlana 1960

Plate dissipation: 37.5W
Max plate voltage: 30000V
Transconductance: 0.7mA/V

GP-5

Characteristics

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

HeaterIndirectly heated

Specifications of GP-5 — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.21 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of GP-5 — Limiting values
Plate voltageVa max	30000 V
Plate dissipationPa max	37.5 W

Mechanical

Specifications of GP-5 — Mechanical
Base	9-pin Magnoval
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of GP-5 — Small signal
Transconductance	0.7 mA/V
Plate resistance	3.9 MΩ
Amplification factor	2750

Capacitances

Specifications of GP-5 — Capacitances
Grid–cathode	4 pF
Grid–plate	0.1 pF
Plate–cathode	1.5 pF

Charactereditorial reading, not a measurement

Specifications of GP-5 — Character
Gain	100%
Power	94%
Drive	0%
Linearity	10%

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

SET output
Push-pull output
High-gain preamp

Generic triode voltage regulator stage

Studio/recordingPA/public address

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Frank/pocnet Svetlana GP-5 · Lampes-et-Tubes

Manufacturer datasheets

1 manufacturer datasheets cross-checked for GP-5 / ГП-51 verified

GP-5 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: Frank/pocnet Svetlana GP-5 · Lampes-et-Tubes
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The GP-5 is a indirectly-heated triode from Svetlana, introduced around 1960. It provides a gain factor (μ) of 2750 with 3900.0kΩ plate resistance. Commonly used in voltage regulator applications. High-voltage shunt regulator. TV / X-ray.

History

Introduced: 1960
Manufacturer: Svetlana
Era: Late Production

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