What is the EF806S vacuum tube?

The EF806S is a pentode vacuum tube designed for preamp applications. Special quality EF86. Ultra-low noise..

What is a EF806S substitute or equivalent?

Direct equivalents to the EF806S include EF86, 6267. 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 EF806S?

Amplification factor μ ≈ 38, transconductance gm ≈ 2 mA/V, plate resistance rp ≈ 2500.0 kΩ, max plate voltage 300 V, max plate dissipation 1 W, heater 6.3 V / 0.2 A.

Is the EF806S still in production?

Production status varies by year and manufacturer. The current Amperatubes catalog classifies the EF806S 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 EF806S sound like?

Special quality EF86. Ultra-low noise.. 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

←EF806S

← EF804S EF86 →Compare → EF86

EF806S Pentode Vacuum Tube

Pentode6.3V / 0.2A9-pin Noval

SourceTelefunkenReviewed2026-05-29StatusDataModelCalcModelunder reviewPDF

Small-signal pentode for low-noise voltage amplification

Datasheet ↗

EF806S — Telefunken — pentode vacuum tube — (1955)

2500.0kΩ

2.0mA/V

4.0pF

0.1pF

5.50pF

GAIN38%

POWER3%

DRIVE0%

LINEARITY81%

SPECIFICATIONS

Heater6.3 V · 0.2 A

Max Plate Voltage300 V

Pa max1 W

Gain Factor38

gm2 mA/V

rp2500.0 kΩ

Inter-electrode capacitances

Cgk4 pF

Cgp0.05 pF

Cpk5.5 pF

Pinout9-pin Noval

Era1955

RaritySought-after

HEATER6.3V / 0.2A

MAX PLATE300V / 1W

BASEnoval

Source datasheets

3 manufacturer datasheets cross-checked for EF806S

3 verified

EXECUTIVE SUMMARY

The EF806S is a indirectly-heated pentode from Telefunken, introduced around 1955. It provides a gain factor (μ) of 38 with 2500.0kΩ plate resistance. Commonly used in preamp applications. Special quality EF86. Ultra-low noise.

APPLICATIONS

Voltage amplifier

Generic pentode preamp stage

VS EF86

μ 0%Rp +0%Pd 0%Full comparison →

HISTORY

Introduced1955ManufacturerTelefunken

Golden Age

EF806S 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.

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