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Voltage Pentode ·Pentode

6BS7

Very-low-microphony pentode designed for extremely sensitive low-level audio preamplification, with practical input levels down to approximately 10 µV.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
9BB
Socket code
B9A
Base pins
9
Nominal heater
6.3 V / 150 mA

Description

Very-low-microphony amplifier pentode for early stages of high-gain audio-frequency amplifiers.

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

9BB - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
2400000 Ω
Transconductance
0.00125 S
Max plate voltage
300 V
Max screen voltage
125 V

Promoted from the printed maximum-rating/characteristic columns; additional operating-point data retained as section parameters.

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

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Heater Voltage

    6.3 V

  • Heater Current

    150 mA

  • MinimumPracticalInputLevel

    10 uV

    HighGainAFAmplifier

Data set 02

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

    100 V

    ClassA

  • Control-grid voltage

    -3 V

    ClassA

  • Plate current

    2.1 mA

    ClassA

  • Screen current

    0.6 mA

    ClassA

Characteristic

  • Plate resistance

    2400000 Ω

    ClassA

  • Transconductance

    1250 µS

    ClassA