14S7

Triode-heptode frequency changer for superheterodyne radio receivers. A separate triode provides local oscillation while the heptode performs frequency conversion, combining the receiver front-end oscillator and mixer functions within one envelope.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 2
Base: 8BL
Socket code: B8G
Base pins: 8
Nominal heater: 12.6 V / 150 mA

Description

The BRIMAR 14S7 is a triode-heptode frequency changer with a 12.6 V heater.

Socket description

Loctal 8-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 8BL
Socket code: B8G
Base pins: 8
Nominal heater voltage: 12.6 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

8BL - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

No fixed ratings are recorded for this section.

Promoted from clearly identified printed ratings/characteristics; additional published operating points and capacitances retained in TUBE_SECTION_PARAMETER.

Section 2

Heptode

X-ray radiationInterelectrode capacitances

Plate resistance: 1250000 Ω
Max plate voltage: 300 V
Max screen voltage: 100 V

Promoted from clearly identified printed ratings/characteristics; additional published operating points and capacitances retained in TUBE_SECTION_PARAMETER.

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

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Oscillator plate voltage
250 V
Converter
Oscillator plate series resistance
20000 Ω
Converter
Oscillator plate current
5 mA
Converter
Oscillator-grid current
0.4 mA
Converter
Oscillator-grid resistor
50000 Ω
Converter

SECTION 2

Heptode

Other

Plate voltage
250 V
Converter
Screen voltage
100 V
Converter
Control-grid voltage
-2 V
Converter
Plate current
1.8 mA
Converter
Screen current
3 mA
Converter

Characteristic

Plate resistance
1250000 Ω
Converter
Conversion transconductance
525 µS
Converter