What is the 5977 vacuum tube?

The 5977 is a triode vacuum tube designed for preamp applications. Military subminiature..

What is a 5977 substitute or equivalent?

Direct equivalents to the 5977 include None. 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 5977?

Amplification factor μ ≈ 16, transconductance gm ≈ 4.5 mA/V, plate resistance rp ≈ 3.6 kΩ, max plate voltage 180 V, max plate dissipation 3.3 W, heater 6.3 V / 0.15 A.

Is the 5977 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 5977 as Rare 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 5977 sound like?

Military subminiature.. 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.

By Jean-Michel Falligan Devergne · Reviewed May 29, 2026

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5977 Triode Vacuum Tube

Triode6.3V / 0.15ASubminiature 9-lead (flying leads, no socket)SPICE

SourceRadiomuseum 5977 / tubebooks RaytheonReviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

5977 — Raytheon — triode vacuum tube — (1958)

3.6kΩ

4.5mA/V

2.0pF

1.3pF

0.80pF

GAIN16%

POWER8%

DRIVE96%

LINEARITY92%

SPECIFICATIONS

Heater6.3 V · 0.15 A

Max Plate Voltage180 V

Pa max3.3 W

Gain Factor16

gm4.5 mA/V

rp3.6 kΩ

Inter-electrode capacitances

Cgk2 pF

Cgp1.3 pF

Cpk0.8 pF

PinoutSubminiature 9-lead (flying leads, no socket)

Era1958

RarityRare

HEATER6.3V / 0.15A

MAX PLATE180V / 3.3W

BASEsubminiature

Source datasheets

5 manufacturer datasheets cross-checked for 5977

5 verified

TYPICAL OPERATING POINT

Va90V

Ia3.87mA

Vg-4V

Pd0.35W

RL7kΩ

Av20.2dB

EXECUTIVE SUMMARY

The 5977 is a indirectly-heated triode from Raytheon, introduced around 1958. It provides a gain factor (μ) of 16 with 3556Ω plate resistance. Commonly used in preamp applications. Military subminiature.

APPLICATIONS

Voltage amplifierLine stage

Generic triode preamp stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced1958ManufacturerRaytheon

Golden Age

5977 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

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