4689

Philips high-output audio pentode for push-pull Class AB service, providing approximately 28.5 W per pair.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: P35-31
Socket code: P8A
Base pins: 8
Nominal heater: 6.3 V / 1.35 A

Description

The Philips 4689 is an indirectly heated output pentode intended for push-pull Class AB audio service.

Socket description

European 8-pin side-contact base

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: P35-31
Socket code: P8A
Base pins: 8
Nominal heater voltage: 6.3 V
Nominal heater current: 1.35 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

P35-31 - 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

Max plate voltage: 375 V
Max screen voltage: 275 V
Max plate dissipation: 18 W
Max screen dissipation: 3.5 W
Max cathode current: 90 mA

Promoted only from clearly identified published characteristics/limits; additional operating, capacitance, regulator, gas-tube, and push-pull 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

1938 Philips Miniwatt Vacuum Tube Catalog

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate voltage
375 V
ClassAB;PushPull;TwoTubes;SelfBias
Screen voltage
275 V
ClassAB;PushPull;TwoTubes;SelfBias
Quiescent plate current per tube
48 mA
ClassAB;PushPull;TwoTubes;SelfBias
Full-modulation plate current per tube
62 mA
ClassAB;PushPull;TwoTubes;SelfBias
Quiescent screen current per tube
5 mA
ClassAB;PushPull;TwoTubes;SelfBias
Full-modulation screen current per tube
9 mA
ClassAB;PushPull;TwoTubes;SelfBias
Common cathode resistor
165 Ω
ClassAB;PushPull;TwoTubes;SelfBias
Optimum plate-to-plate load
6500 Ω
ClassAB;PushPull;TwoTubes;SelfBias
Power output
28.5 W
ClassAB;PushPull;TwoTubes;SelfBias
Total distortion
2.25 %
ClassAB;PushPull;TwoTubes;SelfBias
Grid AC voltage at full modulation
16 V RMS
ClassAB;PushPull;TwoTubes;SelfBias
Maximum plate dissipation per tube
18 W
ClassAB;PushPull;TwoTubes

Data set 02

1957 Philips Receiving and Amplifying Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate Voltage
375 V
ClassAB; PushPull
Screen Voltage
275 V
ClassAB; PushPull
Anode Current
48 mA
ClassAB; PushPull; per tube
Power Output
21.5 W
ClassAB; PushPull; TwoTubes

Data set 03

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

Plate-to-plate load resistance
6.5 kOhm
ClassAB; TwoTubes
Power output
28.5 W
ClassAB; TwoTubes

Capacitance

Anode-grid capacitance
<0.8 pF