6691

Sharp-cutoff RF pentode using a 6.3 V, 0.15 A heater. Manufacturer handbook data document fixed-gain high-frequency amplification with relatively low heater-current demand.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7BD
Socket code: B7G
Base pins: 7
Nominal heater: 6.3 V / 150 mA

Description

6691 is listed in the supplied receiving-tube handbook as a sharp-cutoff RF pentode. The published heater/filament rating is 6.3 V at 0.15 A. Maximum ratings, representative operating characteristics, and available special-service data were captured from the supplied table.

Socket description

Miniature 7-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7BD
Socket code: B7G
Base pins: 7
Nominal heater voltage: 6.3 V
Nominal heater current: 150 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7BD - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G1	A	G1 — Control Grid EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2G3	A	G3 — Suppressor GridGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2IS	A	IS — Internal ScreenGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN2K	A	K — CathodeGroup 7BD2 EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN3H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN4H	—	H — Heater EIA transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN5P	A	P — Plate (Anode) EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN6G2	A	G2 — Screen Grid EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7G3	A	G3 — Suppressor GridGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7IS	A	IS — Internal ScreenGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD
PIN7K	A	K — CathodeGroup 7BD7 EIA chart transcription; manufacturer confirmation pending	Unverified EIA Base Connections, printed page 128, 7BD

Section ratings

1 physical section, each with unique specifications.

Section 1

Pentode

X-ray radiationInterelectrode capacitances

Plate resistance: 500000 Ω
Transconductance: 0.0051 S
Max plate voltage: 180 V
Max screen voltage: 140 V

Published maximum ratings, representative operating conditions, and available capacitance/rectifier data reviewed.

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

Pentode

Other

Maximum plate voltage
180 V
Published handbook rating
Maximum screen voltage
140 V
Published handbook rating
Plate voltage
180 V
ClassA
Screen voltage
120 V
ClassA
Plate current
7.7 mA
ClassA
Screen current
2.4 mA
ClassA

Characteristic

Plate resistance
500000 ohm
Published handbook characteristic
Transconductance
5100 µS
Published handbook characteristic
Heater/filament voltage
6.3 V
Published heater/filament rating
Heater/filament current
150 mA
Published heater/filament rating

Capacitance

Input capacitance
4 pF
Published capacitance column
Output capacitance
2.8 pF
Published capacitance column
Grid-to-plate capacitance
0.02 pF
Published capacitance column