What is the ECC99 vacuum tube?

The ECC99 is a triode vacuum tube designed for driver / power applications. Modern powerhouse..

What is a ECC99 substitute or equivalent?

Direct equivalents to the ECC99 include None direct. 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 ECC99?

Amplification factor μ ≈ 22, transconductance gm ≈ 9.5 mA/V, plate resistance rp ≈ 2.3 kΩ, max plate voltage 400 V, max plate dissipation 5 W, heater 6.3 V / 0.4 A.

Is the ECC99 still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the ECC99 as Common 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 ECC99 sound like?

Modern powerhouse.. 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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ECC99 Triode Vacuum Tube

Dual triode6.3V / 0.4A9-pin NovalSPICE

SourceJJ Electronic ECC99 OEM datasheetReviewed2026-05-29StatusDataModelCalcModelNorman KorenPDF

Medium-gain triode for driver and line stage applications

Datasheet ↗SPICE

ECC99 — JJ Electronic — triode vacuum tube — (2000)

2.3kΩ

9.5mA/V

5.0pF

1.4pF

2.30pF

GAIN22%

POWER13%

DRIVE98%

LINEARITY89%

SPECIFICATIONS

Heater6.3 V · 0.4 A

Max Plate Voltage400 V

Pa max5 W

Gain Factor22

gm9.5 mA/V

rp2.3 kΩ

Inter-electrode capacitances

Cgk5 pF

Cgp1.4 pF

Cpk2.3 pF

Pinout9-pin Noval

Era2000

RarityCommon

HEATER6.3V / 0.4A

MAX PLATE400V / 5W

BASEnoval

SECTIONS2 (dual)

TYPICAL OPERATING POINT

Va250V

Ia17.76mA

Vg-8.94638305V

Pd4.44W

RL6kΩ

Av24.2dB

EXECUTIVE SUMMARY

The ECC99 is a modern dual triode designed by JJ Electronic specifically for audio driver applications, with no direct vintage equivalent. It features a mu of ~22 and unusually low plate resistance (~2.4k ohms per section), giving it exceptional current delivery and load-driving capability for a small-signal tube. The ECC99 can swing large voltages while sourcing significant current, making it an ideal driver for power triodes like the 300B or 2A3 in transformer-coupled or interstage-coupled designs. Its modern design and robust construction make it a practical choice for new amplifier designs that need a strong octal-based driver stage.

APPLICATIONS

Push-pull outputPhase splitter

Generic triode driver / power stage

• Hi-Fi stereo• Headphone amp

HISTORY

Introduced2000ManufacturerJJ Electronic

Modern

ECC99 Datasheet

Local mirror · PDF

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METRIX TESTER

Test this tube on a Metrix

CLASSIC CIRCUITS

Headphone Amp

ECC99 Headphone Output

0.5W

JJ ECC99 as headphone output stage. High-current dual triode designed for low-impedance loads. Drives headphones directly without OPT.

SEVb 200V · Vg -12V · RL 600Ω

JJ ECC99 Datasheet

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