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Voltage Radio Detector Converter ·Diode-Diode-Pentode

6N8

Double-diode pentode combining detector and control-voltage rectification with high-resistance amplification. Paired diodes support detector, discriminator, or automatic-gain-control functions while the pentode supplies substantial gain.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
3
Base
9T
Socket code
B9A
Base pins
9
Nominal heater
6.3 V / 300 mA

Description

Dual-diode pentode for detection and RF or IF amplification; source also designates 6N8.

Socket description

Small-button Noval 9-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
9T
Socket code
B9A
Base pins
9
Nominal heater voltage
6.3 V
Nominal heater current
300 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

9T - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

3 physical sections, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
1400000 Ω
Transconductance
0.0022 S
Max plate voltage
300 V
Max screen voltage
250 V
Max plate dissipation
2 W
Max screen dissipation
0.3 W
Max cathode current
10 mA

Published ratings/characteristics promoted where clearly stated; repeated identical sections compressed where applicable.

Section 2

Diode

X-ray radiationInterelectrode capacitances
Max plate voltage
200 V
Max cathode current
0.8 mA
Rectifier peak inverse voltage
350 V
Rectifier nominal output current
0.8 mA

Promoted from printed maximum-rating/characteristic columns; additional published operating points and capacitances retained as parameters.

Section 3

Diode

X-ray radiationInterelectrode capacitances
Max plate voltage
200 V
Max cathode current
0.8 mA
Rectifier nominal output current
0.8 mA

Promoted values and additional parameters were taken from the supplied Ferranti datasheet tables.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1953 RFT Rundfunk Technik

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • HeaterVoltageNominal

    6.3 V

    Nominal

  • HeaterCurrentNominal

    300 mA

    Nominal

  • Maximum Plate Voltage

    300 V

  • Maximum Screen Voltage

    300 V

  • Maximum Plate Dissipation

    1.5 W

  • Maximum Screen Dissipation

    0.3 W

SECTION 2

Diode

Characteristics

  • Heater voltage

    6.3 V

    Published nominal value

  • Heater current

    300 mA

    Published nominal value

  • Transconductance

    2200 µS

    Published operating characteristic

Other

  • Maximum plate dissipation

    1.7 W

    Published maximum rating

Data set 02

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Cutoff characteristic

    Variable-mu

Application

  • Application

    RF / IF amplifier

SECTION 2

Diode

Application

  • Application

    Signal detection

Data set 03

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    250 V

    ClassA

  • Screen voltage

    85 V

    ClassA

  • Cathode resistor

    295 Ω

    ClassA

  • Plate current

    5 mA

    ClassA

  • Screen current

    1.75 mA

    ClassA

Characteristic

  • Plate resistance

    1600000 Ω

    ClassA

  • Transconductance

    2200 µS

    ClassA

  • Amplification factor

    35

    ClassA

Data set 04

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate voltage

    250 V

    PentodeSection

  • Control-grid voltage

    -2 V

    PentodeSection

  • Plate current

    5 mA

    PentodeSection

  • Screen-grid current

    1.75 mA

    PentodeSection

Characteristics

  • Transconductance

    2200 uS

    PentodeSection

  • Plate resistance

    1500000 Ohm

    PentodeSection

  • Screen-to-control-grid amplification factor

    18 ratio

    PentodeSection

  • Control-grid voltage for gm=22uS

    -41.5 V

    PentodeSection

Capacitance

  • Input capacitance

    4 pF

    PentodeSection

  • Output capacitance

    4.9 pF

    PentodeSection

  • Grid-to-plate capacitance maximum

    0.0025 pF

    PentodeSection

SECTION 2

Diode

Other

  • Diode current maximum

    0.8 mA

    Diode1

  • Peak diode plate voltage

    200 V

    Diode1

SECTION 3

Diode

Other

  • Diode current maximum

    0.8 mA

    Diode2

  • Peak diode plate voltage

    200 V

    Diode2

Data set 05

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

  • Application

    RF_IF_Amplifier text

SECTION 2

Diode

Application

  • Application

    Detector text

Data set 06

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Heater voltage

    6.3 V

  • Heater current

    300 mA

  • Plate voltage (without current)

    550 volts

    PublishedLine: Plate voltage (without current) 550 volts

  • Plate dissipation

    2 watts

    PublishedLine: Plate dissipation 2 watts

  • Screen grid voltage (without current)

    550 volts

    PublishedLine: Screen grid voltage (without current) 550 volts

  • S reen grid voltage (plate current

    5 ma

    PublishedLine: Séreen grid voltage (plate current = 5 ma) 125 volts

  • Screen grid dissipation

    0.3 watts

    PublishedLine: Screen grid dissipation 0.3 watts

  • cathode

    3 megohms

    PublishedLine: ' cathode 3 megohms 1)

  • Volta e between heater and cathode

    50 volts

    PublishedLine: Volta;e between heater and cathode 50 volts

  • Flate voltage (veak value)

    200 volts

    PublishedLine: Flate voltage (veak value) 200 volts

  • Plate voltage at plate current

    -1.3 volts

    PublishedLine: Plate voltage at plate current = +0.3 ua -1.3 volts

  • Voltage bLetween heater and cathode

    50 volts

    PublishedLine: Voltage bLetween heater and cathode 50 volts

Other

  • Pentode plate voltage

    250 V

    Section1

  • Pentode plate dissipation

    2 W

    Section1

  • Pentode screen voltage

    250 V

    Section1

  • Pentode screen dissipation

    0.3 W

    Section1

  • Pentode cathode current

    10 mA

    Section1

  • Plate and supply voltage

    250 volts

    PublishedLine: Plate and supply voltage 250 volts

  • Grid No

    0 volts

    PublishedLine: Grid No.3 wvoltage 0} volts

  • Screen grid series resistor

    95000 ohms

    PublishedLine: Screen grid series resistor 95,000 ohms

  • Cathode resistor

    225 ohms

    PublishedLine: Cathode resistor 225 ohms

  • Grid No

    -41.5 volts

    PublishedLine: Grid No.1 voltage 22 -41.5' volts

  • Screen grid voltage

    250 volts

    PublishedLine: Screen grid voltage 85 250 volts

  • Plate current

    5 amps

    PublishedLine: Plate current 5 - milli-amps

  • Screen grid current

    1.75 amps

    PublishedLine: Screen grid current 1,75 - milli.-amps

SECTION 2

Diode

Other

  • Diode peak plate voltage

    200 V

    Section2 Section3