What is the 12B-EmissionLabs vacuum tube?

The 12B-EmissionLabs (12B EML) is a triode vacuum tube designed for power (set) applications. EML DHT triode..

What is a 12B-EmissionLabs substitute or equivalent?

Direct equivalents to the 12B-EmissionLabs 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 12B-EmissionLabs?

Amplification factor μ ≈ 12, transconductance gm ≈ 3.5 mA/V, plate resistance rp ≈ 3.4 kΩ, max plate voltage 600 V, max plate dissipation 25 W, heater 5 V / 2.5 A.

Is the 12B-EmissionLabs still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the 12B-EmissionLabs as Sought-after 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 12B-EmissionLabs sound like?

EML DHT triode.. 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 10, 2026

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12B-EmissionLabs 12B EML Triode Vacuum Tube

Triode5V / 2.5AUX-4SPICE

SourceEmission Labs design notes (EML-12B-20A-20B-30A) · external audit feedbackReviewed2026-05-10StatusDataModelCalcModelNorman KorenPDF

Power triode delivering 25W for push-pull and SET designs

Datasheet ↗SPICE

12B EML — Emission Labs — triode vacuum tube — (2008)

3.4kΩ

3.5mA/V

8.0pF

14.0pF

6.00pF

GAIN12%

POWER63%

DRIVE97%

LINEARITY94%

SPECIFICATIONS

Heater5 V · 2.5 A

Max Plate Voltage600 V

Pa max25 W

Gain Factor12

gm3.5 mA/V

rp3.4 kΩ

Inter-electrode capacitances

Cgk8 pF

Cgp14 pF

Cpk6 pF

PinoutUX-4

Era2008

RaritySought-after

HEATER5V / 2.5A

MAX PLATE600V / 25W

BASEux4

TYPICAL OPERATING POINT

Va450V

Ia44.04mA

Vg-18.7V

Pd19.82W

RL7kΩ

Av20.7dB

EXECUTIVE SUMMARY

The 12B-EmissionLabs is a directly-heated triode from Emission Labs, introduced around 2008. It provides a gain factor (μ) of 12 with 3400Ω plate resistance. Commonly used in power (set) applications. EML DHT triode.

APPLICATIONS

SET outputPush-pull output

Generic triode power (set) stage

• Hi-Fi stereo

HISTORY

Introduced2008ManufacturerEmission Labs

Modern

12B-EmissionLabs Datasheet

Frank's Electron Tube Pages · PDF

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METRIX TESTER

Test this tube on a Metrix

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