What is the 6S45P vacuum tube?

The 6S45P (6S45P / 6С45П) is a triode vacuum tube designed for preamp / driver applications. Ultra-high Gm. Gold grid. Stunning speed..

What is a 6S45P substitute or equivalent?

Direct equivalents to the 6S45P include WE437A, 6C45Pi. 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 6S45P?

Amplification factor μ ≈ 52, transconductance gm ≈ 45 mA/V, plate resistance rp ≈ 1.1 kΩ, max plate voltage 150 V, max plate dissipation 7.8 W, heater 6.3 V / 0.44 A.

Is the 6S45P still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6S45P 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 6S45P sound like?

Ultra-high Gm. Gold grid. Stunning speed.. 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.

6S45P 6С45П Triode Vacuum Tube

Also known as WE437A · 6C45Pi

Medium-gain triode for driver and line stage applications

TriodeHeater 6.3 V · 0.44 A9-pin NovalReflector 1965

Plate dissipation: 7.8W
Max plate voltage: 150V
Transconductance: 45mA/V

6S45P

Characteristics

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

HeaterIndirectly heated

Specifications of 6S45P — Heater
Heater voltageVh	6.3 V
Heater currentIh	0.44 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 6S45P — Limiting values
Plate voltageVa max	150 V
Plate dissipationPa max	7.8 W

Mechanical

Specifications of 6S45P — Mechanical
Base	9-pin Noval
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 6S45P — Small signal
Transconductance	45 mA/V
Plate resistance	1.1 kΩ
Amplification factor	52

Capacitances

Specifications of 6S45P — Capacitances
Grid–cathode	11 pF
Grid–plate	4 pF
Plate–cathode	1.9 pF

Charactereditorial reading, not a measurement

Specifications of 6S45P — Character
Gain	52%
Power	20%
Drive	99%
Linearity	74%

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

Push-pull output
Voltage amplifier
Headphone output
High-gain preamp

Generic triode preamp / driver stage

Hi-Fi stereoHeadphone ampStudio/recording

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : Soviet-Tubes 6С45П-Е datasheet

Manufacturer datasheets

1 manufacturer datasheets cross-checked for 6S45P / 6С45П1 verified

6S45P DatasheetFrank's Electron Tube Pages · PDF

SPICE models

Revision and verification status

Source: Soviet-Tubes 6С45П-Е datasheet
Reviewed: 2026-05-29
Status: DataModelCalc
Model: under review

Context

The 6S45P is a indirectly-heated triode from Reflector, introduced around 1965. It provides a gain factor (μ) of 52 with 1150Ω plate resistance. Commonly used in preamp / driver applications. Ultra-high Gm. Gold grid. Stunning speed.

History

Introduced: 1965
Manufacturer: Reflector
Era: Late Production

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