6281

Directly heated subminiature pentode for resistance-coupled audio and direct-coupled amplifiers. Manufacturer documentation emphasizes low battery drain, long life, and low microphonics, making it well suited to compact low-level audio equipment.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: SUBMINIATURE8
Base pins: 8
Nominal heater: 0.625 V / 20 mA

Description

Directly heated subminiature pentode for resistance-coupled audio and direct-coupled amplifiers, with low battery drain, long life and low microphonics.

Socket description

Subminiature 8-lead base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: SUBMINIATURE8
Base pins: 8
Nominal heater voltage: 0.625 V
Nominal heater current: 20 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

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

Transconductance: 0.00016 S
Max plate voltage: 45 V
Max screen voltage: 45 V

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

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

1938 Raytheon

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

Heater or filament voltage
0.625 V
Published nominal or representative value
Heater or filament current
20 mA
Published nominal or representative value
Transconductance
160 µS
Published operating characteristic