What is the 5687 vacuum tube?

The 5687 is a triode vacuum tube designed for driver applications. Muscular bass control..

What is a 5687 substitute or equivalent?

Direct equivalents to the 5687 include 5687WA. 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 5687?

Amplification factor μ ≈ 16, transconductance gm ≈ 5.4 mA/V, plate resistance rp ≈ 3.0 kΩ, max plate voltage 300 V, max plate dissipation 4.2 W, heater 12.6 V / 0.45 A.

Is the 5687 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 5687 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 5687 sound like?

Muscular bass control.. 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.

5687 Triode Vacuum Tube

Also known as 5687WA

Medium-gain triode for driver and line stage applications

Dual triodeHeater 12.6 V · 0.45 A9-pin Noval2 sectionsTung-Sol·GE 1955

Plate dissipation: 4.2W
Max plate voltage: 300V
Amplification factor: 16
Transconductance: 5.4mA/V
Plate resistance: 3kΩ

5687

Characteristics

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

HeaterIndirectly heated

Specifications of 5687 — Heater
Heater voltageVh	12.6 V
Heater currentIh	0.45 A

Limiting valuesDatasheet maximum ratings — not to be exceeded

Specifications of 5687 — Limiting values
Plate voltageVa max	300 V
Plate dissipationPa max	4.2 W
Heater–cathode voltageVhk max	100 V

Mechanical

Specifications of 5687 — Mechanical
Base	9-pin Noval
Rarity	Moderate
Pinout

Small signalDatasheet parameters at the reference operating point — not limits

Specifications of 5687 — Small signal
Transconductance	5.4 mA/V
Plate resistance	3 kΩ
Amplification factor	16

Capacitances

Specifications of 5687 — Capacitances
Grid–cathode	4 pF
Grid–plate	4 pF
Plate–cathode	0.6 pF

Charactereditorial reading, not a measurement

Specifications of 5687 — Character
Gain	16%
Power	11%
Drive	97%
Linearity	92%

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

Typical operation

Canonical operating pointSPICE model2 availableModel

B+: 300 V
Load: 6 kΩ
Va: 180 V
Ia: 17.17 mA
Vg: -7.5 V
Pd: 3.09 W
Gain: 22.1 dB

At Q: Ayumi Nakabayashi · 2 engines
μ: 16.9
gm: 7.32 mA/V
rp: 2.3 kΩ

Design a stage →

Using this tube

Applications

Line stage
Phase splitter

Generic triode driver stage

Headphone amp

Replace or compare

Sources

By Jean-Michel Falligan DevergneReviewed May 29, 2026Source : TubeWorld 5687 datasheet · cap audit 2026-05-09Active model : Ayumi Nakabayashi · 2 engines

Manufacturer datasheets

3 manufacturer datasheets cross-checked for 56873 verified

5687 DatasheetLocal mirror · PDF

SPICE models

Revision and verification status

Source: TubeWorld 5687 datasheet · cap audit 2026-05-09
Reviewed: 2026-05-29
Status: DataModelCalc
Model: Ayumi Nakabayashi · 2 engines

Context

The 5687 is a medium-mu (mu ~18) dual triode originally designed for computer and instrumentation use, built to extreme standards of reliability and vibration resistance. It can handle significantly more plate current than a 6SN7 (up to 30mA per section) while maintaining low distortion, making it an excellent driver tube for demanding loads. The military pedigree means consistent quality and rugged construction, with many examples still testing as new after decades. Tung-Sol and GE are the primary NOS manufacturers; the tube has become a favorite of headphone amplifier designers for its combination of linearity and current drive.

History

Introduced: 1955
Manufacturer: Tung-Sol·GE
Era: Golden Age

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