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Voltage Pentode ·Pentode

6688A

A-suffix variant of the high-transconductance 6688 broadband pentode, retaining professional wideband amplifier characteristics.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B9A
Base pins
9
Nominal heater
6.3 V / 300 mA

Description

A-suffix broad-band amplifier pentode of the 6688 family, retaining the high-transconductance wide-band characteristics.

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
-
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

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
3300 Ω
Transconductance
0.0165 S
Amplification factor
50
Max plate dissipation
3 W

Broad-band amplifier pentode A variant.

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

1963 Amperex Condensed

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Maximum plate dissipation

    3 W

  • Plate voltage

    175 V

  • Screen voltage

    160 V

  • Plate current

    13 mA

Characteristic

  • Plate resistance

    3.3 kOhm

  • Transconductance

    16500 uS

  • Amplification Factor

    50