What is the 6900 vacuum tube?

The 6900 is a triode vacuum tube designed for driver / preamp applications. Bendix premium. Military-spec 5687. Holy grail..

What is a 6900 substitute or equivalent?

Direct equivalents to the 6900 include 5687, 7044. 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 6900?

Amplification factor μ ≈ 18, transconductance gm ≈ 11.5 mA/V, plate resistance rp ≈ 1.7 kΩ, max plate voltage 600 V, max plate dissipation 4.25 W, heater 12.6 V / 0.45 A.

Is the 6900 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 6900 as Collector 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 6900 sound like?

Bendix premium. Military-spec 5687. Holy grail.. 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

←6900

← 6888 6922 →Compare → 5687

6900 Triode Vacuum Tube

Dual triode12.6V / 0.45A9-pin Noval

SourceBendixReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗

6900 — Bendix — triode vacuum tube — (1960)

1.7kΩ

11.5mA/V

6.5pF

4.0pF

0.80pF

GAIN18%

POWER11%

DRIVE98%

LINEARITY91%

SPECIFICATIONS

Heater12.6 V · 0.45 A

Max Plate Voltage600 V

Pa max4.25 W

Gain Factor18

gm11.5 mA/V

rp1.7 kΩ

Inter-electrode capacitances

Cgk6.5 pF

Cgp4 pF

Cpk0.8 pF

Pinout9-pin Noval

Era1960

RarityCollector

HEATER12.6V / 0.45A

MAX PLATE600V / 4.25W

BASEnoval

SECTIONS2 (dual)

Source datasheets

2 manufacturer datasheets cross-checked for 6900

2 verified

EXECUTIVE SUMMARY

The 6900 is a dual indirectly-heated triode from Bendix, introduced around 1960. It provides a gain factor (μ) of 18 with 1700Ω plate resistance. Commonly used in driver / preamp applications. Bendix premium. Military-spec 5687. Holy grail.

APPLICATIONS

Voltage amplifierHeadphone outputLine stagePhase splitter

Generic triode driver / preamp stage

• Hi-Fi stereo• Headphone amp

VS 5687

μ +13%Rp -43%Pd +1%Full comparison →

HISTORY

Introduced1960ManufacturerBendix

Late Production

6900 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

SPICE model not yet available. Loadline calculator requires calibrated Koren parameters.

SIMILAR TRIODES

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