Skip to main content
Tube Tinker — Electron Tube Database
Alternatives & variationsDownload PDF datasheet

Power - Pentode (NOT beam) ·Pentode

UL84

High-transconductance series-heater audio power pentode for Class A and push-pull Class AB output.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
-
Socket code
B9A
Base pins
9
Nominal heater
45 V / 100 mA

Description

Power pentode for Class A and two-tube Class AB low-frequency audio output amplification.

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
45 V
Nominal heater current
100 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
28000 Ω
Transconductance
0.01 S
Max plate voltage
550 V
Max screen voltage
300 V
Max plate dissipation
12 W
Max screen dissipation
1.75 W
Max cathode current
100 mA

Published ratings and characteristics promoted from the approved source.

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

1953 La Radiotechnique

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Plate Voltage

    170 V

    ClassA

  • Screen Voltage

    170 V

    ClassA

  • Grid Voltage

    -12.5 V

    ClassA

  • Plate Current

    70 mA

    ClassA

  • Screen Current

    5 mA

    ClassA

  • OutputPower

    5.6 W

    ClassA

  • Total Distortion

    10 percent

    ClassA

  • Load Impedance

    2400 Ohm

    ClassA

  • OutputPower

    13.55 W

    ClassB;PushPull;TwoTubes;Va=170V

  • OutputPower

    13 W

    ClassAB;PushPull;TwoTubes;Va=170V

  • OutputPower

    2.1 W

    ClassA;TriodeConnection;Va=170V

  • OutputPower

    3.9 W

    ClassAB;PushPull;TwoTubes;TriodeConnection;Va=170V

Capacitance

  • Input Capacitance

    12 pF

  • Output Capacitance

    6 pF

  • Plate To Grid Capacitance

    0.6 pF

Data set 02

1957 Philips Receiving and Amplifying Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Heater Voltage

    45 V

  • Heater Current

    100 mA

Other

  • Plate Voltage

    170 V

    ClassA

  • Plate Current

    70 mA

    ClassA

  • Maximum Signal Power Output

    5.3 W

    ClassA

Data set 03

195X Tesla

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • HeaterVoltageNominal

    45 V

    Nominal

  • HeaterCurrentNominal

    100 mA

    Nominal

  • Maximum Plate Voltage

    550 V

  • Maximum Screen Voltage

    300 V

  • Maximum Plate Dissipation

    12 W

Data set 04

1961 Ferranti Technical Handbook

Published operating points and test conditions from this source.

SECTION 1

Pentode

Application

  • Application

    Audio output

Other

  • Class-A audio operation

    Published

    ClassA

Data set 05

1963 Philips Electron Tubes Handbook V1

Published operating points and test conditions from this source.

SECTION 1

Pentode

Capacitance

  • Anode capacitance

    6.8 pF

  • Control-grid capacitance

    13 pF

  • Anode-to-control-grid capacitance

    - to 0.6 pF

    Maximum

  • Control-grid-to-heater capacitance

    - to 0.25 pF

    Maximum

Characteristic

  • Plate voltage

    170 V

    Typical

  • Screen voltage

    170 V

    Typical

  • Grid voltage

    -12.5 V

    Typical

  • Plate current

    70 mA

    Typical

  • Screen current

    3.5 mA

    Typical

  • Transconductance

    11000 uS

    Typical

  • Plate resistance

    26 kOhm

    Typical

Other

  • Plate supply voltage

    170 V

    ClassA; OneTube

  • Load resistance

    2 kOhm

    ClassA; OneTube

  • Power output

    5.1 W

    ClassA; OneTube

  • Plate supply voltage

    200 V

    ClassA; OneTube

  • Load resistance

    2.5 kOhm

    ClassA; OneTube

  • Power output

    5.3 W

    ClassA; OneTube

  • Plate supply voltage

    200 V

    ClassAB; PushPull; TwoTubes

  • Load resistance plate-to-plate

    3 kOhm

    ClassAB; PushPull; TwoTubes

  • Power output

    14.3 W

    ClassAB; PushPull; TwoTubes

  • Distortion

    3.8 %

    ClassAB; PushPull; TwoTubes

Data set 06

1967 Mullard Receiving and Amplifying Valves

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristic

  • Output pentode roted (or

    12

    Characteristic

  • *Vg2 (b ) =

    4700

    CHARACTERISTICS

Other

  • Va

    200 V

    OPERATING CONDITIONS AS SINGLE VALVE AMPLIFIER

  • Vg

    170 V

    OPERATING CONDITIONS AS SINGLE VALVE AMPLIFIER

  • Ra

    2.4 kO

    OPERATING CONDITIONS AS SINGLE VALVE AMPLIFIER

  • *Vg

    47012

    OPERATING CONDITIONS AS SINGLE VALVE AMPLIFIER

  • approximately

    10

    OPERATING CONDITIONS AS SINGLE VALVE AMPLIFIER

  • Va

    200 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Vg

    200 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Ra _ a

    3.5 a

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Pout

    15 W

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Distri buted load conditions w it h screen-grid tapping at

    20 w

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Va + VRk

    200 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Vg2 + VR k

    200 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Va l b ) max

    550 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Va max

    250 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Vg

    550 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Vg2 max

    200 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • I " Ve = Vg

    0 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • 2: Ve = Vg2 = 17 0 V

    0 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • 3 : Ve ~ Vg2 = 10 0 V II I

    0 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Vg l (V)

    0 V

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • CO NTROL-GRID VOLTAGE AS PARAMETER. Vg2 =

    100

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • CO NTRO L-GRID VO LTA GE AS PARAM ETER. Vg

    170

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • CO NTROL-GRID VOLTAGE AS PARAMETER. Vg

    200

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • PERFORMANC E OF UL8

    4 W

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • v« = V g

    100 v

    OPERATING CONDITIONS FOR TWO VALVES IN PUSH-PULL

  • Va = Vg2 =

    170

    PERFORMANCE OF UL84 WHEN USED AS SINGLE VALVE AMPLIFIER

  • PERFO RMA N CE OF UL8

    4

    PERFORMANCE OF UL84 WHEN USED AS SINGLE VALVE AMPLIFIER

Data set 07

1968 Mazda Belvu

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • Power Output

    5.3 W

    ClassA;OneTube;Supply 200 V;Load 2.5 kohm

  • Power Output

    14.3 W

    ClassAB;PushPull;TwoTubes;Supply 200 V;Load 3 kohm

Data set 08

1972 Philips Receiving Tubes

Published operating points and test conditions from this source.

SECTION 1

Pentode

Other

  • HeaterVoltageNominal

    45 V

    Nominal

  • HeaterCurrentNominal

    100 mA

    Nominal

  • Maximum Plate Voltage

    250 V

  • Maximum Screen Voltage

    200 V

  • Maximum Plate Dissipation

    12 W

  • Maximum Screen Dissipation

    1.75 W

  • Maximum Cathode Current

    100 mA

Characteristic

  • Transconductance

    11000 µS

    Typical

  • Amplification Factor

    8

    Typical

  • Plate Resistance

    26000 ohm

    Typical

Data set 09

1999 Philips E-Z

Published operating points and test conditions from this source.

SECTION 1

Pentode

Characteristics

  • Capacitances Ca 6,0 pF

    6 a

    Capacitances Ca 6,0 pF

  • Capacités ) 3

    3 a

    Capacités ) 3

  • Capacitances Ca

    6 a

    Capacitances Ca = 6,0 pF

  • Capacites c

    12 a

    Capacites c = 12,0 pF

  • Capacités Cq

    6.8 a

    Capacités Cq = 6,8 pF

  • A (Grille-écran relide a 1'anode)

    1 A

    A (Grille-écran relide a 1'anode)

  • en montage triode (Grille-écran relide a 1'anode)

    1 a

    en montage triode (Grille-écran relide a 1'anode)

  • 4 (Grille-écran reliée a 1'anode

    4 a

    4 (Grille-écran reliée a 1'anode

  • en montage triode (Grille-écran reliée a 1'anode)

    1 a

    en montage triode (Grille-écran reliée a 1'anode)

  • 9 With automatic grid bias

    9 W

    9 With automatic grid bias

  • 1)With automatic grid bias

    1 W

    1)With automatic grid bias