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Power - Pentode (NOT beam) ·Pentode-Triode

11KV8

Miniature triode-pentode for television voltage amplification, sync separation, sound IF, and video output. Its pentode section uses frame-grid construction for high-transconductance wideband output service.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
2
Base
9DX
Socket code
B9A
Base pins
9
Nominal heater
10.9 V / 450 mA

Description

11KV8 — High-Mu Triode and Sharp-Cutoff Pentode

The 11KV8 is a miniature multi-unit vacuum tube containing a high-mu triode and a sharp-cutoff pentode within a single envelope. Designed primarily for use in black-and-white television receivers, the tube's independent sections are tailored for distinct roles: the triode unit is designed for general-purpose voltage-amplifier, sync-separator, and sound-IF-amplifier applications, while the pentode unit features a frame-grid construction optimized for service as a video-output amplifier.

The 11KV8 is electrically identical to the 6KV8 except for its heater characteristics, making it suitable for series-string heater arrangements requiring controlled warm-up times.

Physical Specifications and Basing

The 11KV8 is constructed in a miniature T-6 1/2 glass envelope with a 9-pin button base (E9-1 designation). It utilizes the 9DX basing arrangement, which provides separate connections for the triode and pentode electrodes, with the pentode's suppressor grid, cathode, and internal shield sharing a common pin.

Physical Dimensions

  • Maximum Diameter: 0.875 inches
  • Maximum Seated Height: 2.375 inches
  • Maximum Overall Height: 2.625 inches
  • Outline Classification: 6-3

Pin Connection Diagram (9DX Base)

The pin connections, viewed from the bottom of the tube base, are assigned as follows:

  • Pin 1: Triode Grid (GT)
  • Pin 2: Triode Cathode (KT)
  • Pin 3: Triode Plate (PT)
  • Pin 4: Heater (H)
  • Pin 5: Heater (H)
  • Pin 6: Pentode Grid No. 1 / Control Grid (G1P)
  • Pin 7: Pentode Grid No. 3 / Suppressor Grid, Pentode Cathode, Internal Shield (G3P, KP, IS)
  • Pin 8: Pentode Grid No. 2 / Screen Grid (G2P)
  • Pin 9: Pentode Plate (PP)

Heater and Heater-Cathode Ratings

The 11KV8 heater is designed for series-string operation with a controlled warm-up sequence to minimize voltage surges in television receiver strings.

ParameterValue
Heater Voltage (AC or DC)10.9 V
Heater Current0.450  0.030 A
Average Heater Warm-up Time11 seconds

Heater-Cathode Voltage Limits

To prevent insulation breakdown between the heater and the cathodes, the following maximum ratings must be observed:

  • Heater Negative with Respect to Cathode: 200 V (Peak or Total DC + Peak)
  • Heater Positive with Respect to Cathode: 100 V DC maximum, 200 V (Peak or Total DC + Peak)
  • Average Value: 100 V maximum

Electrical Characteristics and Typical Operation

The triode section provides high voltage gain with moderate plate resistance, while the pentode section features exceptionally high transconductance (exceeding 20,000 mhos) due to its frame-grid design. Typical Class A operating points for both sections are detailed below:

ParameterTriode SectionPentode Section (Point A)Pentode Section (Point B)
Plate Supply Voltage200 V125 V200 V
Grid No. 2 (Screen) Supply Voltage—125 V125 V
Grid No. 1 (Control) Supply Voltage-2 V0 V0 V
Cathode-Bias Resistor—82 ̤68 ̤
Amplification Factor70——
Plate Resistance (Approx.)17,500 ̤55,000 ̤75,000 ̤
Transconductance4,000 mhos21,000 mhos23,000 mhos
Plate Current4.0 mA16.5 mA20.0 mA
Grid No. 2 Current—3.1 mA3.5 mA
Grid No. 1 Voltage for Ib = 100 A (Approx.)-4.5 V-4.2 V-4.2 V

Design-Maximum Ratings

The ratings below are established under the Design-Maximum Rating System. Operating the tube beyond these limits may impair its reliability and performance.

RatingTriode SectionPentode Section
Maximum Plate Voltage300 V300 V
Maximum Grid No. 2 Supply Voltage—300 V
Maximum Grid No. 2 Voltage—See Rating Chart
Maximum Positive Grid No. 1 Voltage0 V0 V
Maximum Plate Dissipation1.0 W5.0 W
Maximum Grid No. 2 Dissipation (up to 150 V)—1.1 W
Maximum Grid No. 2 Dissipation (150 V to 300 V)—See Rating Chart

Maximum Grid No. 1 Circuit Resistance

  • Triode Section: 0.5 M̤ (Fixed Bias), 1.0 M̤ (Cathode Bias)
  • Pentode Section: 0.1 M̤ (Fixed Bias), 0.25 M̤ (Cathode Bias)

Special Testing and Handling Precaution

The physical spacing between the control grid (Grid No. 1) and the cathode in the pentode section is extremely small. Because of this close spacing, testing the tube in commercial tube checkers or shorts-indicating devices requires caution. To prevent damage or false readings, the voltage applied between the control grid and cathode must not exceed 50 volts DC or peak AC, particularly when the tube is subjected to mechanical excitation or vibration during testing.

Direct Interelectrode Capacitances

The capacitances listed below are measured without an external shield:

Triode Section

  • Grid to Plate: 3.7 pF
  • Input (Grid to Heater + Triode Cathode + Pentode Cathode + Pentode Grid No. 3 + Internal Shield): 2.5 pF
  • Output (Plate to Heater + Triode Cathode + Pentode Cathode + Pentode Grid No. 3 + Internal Shield): 2.4 pF

Pentode Section

  • Grid No. 1 to Plate (Maximum): 0.12 pF
  • Input (Grid No. 1 to Heater + Pentode Cathode + Pentode Grid No. 3 + Internal Shield + Grid No. 2): 13 pF
  • Output (Plate to Heater + Pentode Cathode + Pentode Grid No. 3 + Internal Shield + Grid No. 2): 4.8 pF

Inter-Section Coupling

  • Triode Grid to Pentode Plate (Maximum): 0.015 pF
  • Pentode Plate to Triode Plate (Maximum): 0.17 pF

Related Designations and Curves

The 11KV8 is part of a family of high-performance television receiver tubes. It shares its physical structure, electrode configuration, and electrical characteristics with the 6KV8, differing only in its heater requirements (the 6KV8 operates at 6.3 V and 0.775 A).

For detailed graphical representations of the average plate characteristics of the triode unit, reference is made to the curves published for the 6AW8A vacuum tube, which exhibits identical triode plate 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
9DX
Socket code
B9A
Base pins
9
Nominal heater voltage
10.9 V
Nominal heater current
450 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

9DX - Terminal pinout

Electrical assignments shared by every tube using this base designation.

TerminalSectionConnectionEvidence
PIN12KBK — Cathode

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN22G1BG1 — Control Grid

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN32PBP — Plate (Anode)

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN4H—H — Heater

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN5H—H — Heater

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN61G3AG3 — Suppressor GridGroup 9DX6

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN6ISAIS — Internal ScreenGroup 9DX6

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN61KAK — CathodeGroup 9DX6

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN71G1AG1 — Control Grid

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN81G2AG2 — Screen Grid

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

PIN91PAP — Plate (Anode)

EIA transcription; manufacturer confirmation pending

Unverified

EIA Base Connections, printed page 131, 9DX

Section ratings

2 physical sections, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances
Plate resistance
20000 Ω
Transconductance
0.004 S
Amplification factor
100
Max plate voltage
300 V
Max plate dissipation
2 W

high-mu

Section 2

Pentode

X-ray radiationInterelectrode capacitances
Plate resistance
75000 Ω
Transconductance
0.023 S
Max plate voltage
300 V
Max screen voltage
300 V
Max plate dissipation
5 W
Max screen dissipation
1 W

sharp-cutoff

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

1971 RCA HB3 Binder 5 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

  • Maximum Plate Voltage

    300 V

    Inherited from explicitly referenced 6-volt parent type

  • Plate Dissipation

    2 W

    Inherited from explicitly referenced 6-volt parent type

SECTION 2

Pentode

Other

  • Maximum Plate Voltage

    300 V

    Inherited from explicitly referenced 6-volt parent type

  • Plate Dissipation

    5 W

    Inherited from explicitly referenced 6-volt parent type

Data set 02

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Triode

Capacitance

  • Grid to Plate

    3.7 pF

  • Grid to other electrodes

    2.5 pF

  • Plate to other electrodes

    2.4 pF

Other

  • Plate supply voltage

    200 V

    ClassA

  • Plate current

    4 mA

    ClassA

SECTION 2

Pentode

Capacitance

  • Grid No.1 to Plate

    0.12 pF

  • Grid No.1 to other electrodes

    13 pF

  • Plate to other electrodes

    4.8 pF

Other

  • Plate supply voltage

    125 V

    ClassA

  • Screen-grid supply voltage

    125 V

    ClassA

  • Plate current

    16.5 mA

    ClassA

  • Screen-grid current

    3.1 mA

    ClassA