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Power - Beam Single (NOT sweep) (under 10W) ·BeamPower

11DS5

Miniature beam-power output tube intended for Class-A audio-frequency output stages in television and radio receivers, delivering several watts from a compact receiving-tube envelope.

Directly heatedCold cathodeCommon cathodeDissimilar
Sections
1
Base
7BZ
Socket code
-
Base pins
7
Nominal heater
11.2 V / 450 mA

Description

11DS5

The 11DS5 is a miniature beam power tube designed primarily for use in the audio output stages of television and radio receivers.

Overview

The 11DS5 is a glass-envelope miniature beam power tube. It is designed for Class A1 audio power amplification, making it highly suitable for the audio output stages of television and radio receivers. The tube is constructed in a compact form factor requiring a standard miniature 7-contact socket.

In terms of its physical construction and electrical characteristics, the 11DS5 is identical to the 6DS5, with the sole exception of its heater ratings. While the 6DS5 is designed for standard 6.3 V heater supplies, the 11DS5 is designed with an 11.2 V heater, making it suitable for series-string heater arrangements or specific power supply configurations.

Heater Characteristics and Basing

The 11DS5 features an indirectly heated, coated cathode. The heater is designed for operation on either AC or DC power supplies.

Heater Ratings

  • Heater Voltage (AC/DC): 11.2 V
  • Heater Current: 0.450 A (with an allowable tolerance of  0.030 A)
  • Heater Warm-up Time (Average): 11 seconds
  • Peak Heater-Cathode Voltage: 200 V maximum
  • Calculated Heater Power: 5.04 W (calculated as 11.2 V  0.45 A)

7BZ Pin Connection Diagram

The tube utilizes a miniature 7-contact base (designated 7BZ). When viewed from the bottom of the tube, the pin assignments are as follows:

  • Pin 1: Grid No.1 (Control Grid)
  • Pin 2: Cathode and Grid No.3 (Beam Plates)
  • Pin 3: Heater
  • Pin 4: Heater
  • Pin 5: Plate
  • Pin 6: Grid No.2 (Screen Grid)
  • Pin 7: Grid No.1 (Control Grid)

Grid No.1 is internally connected to both Pin 1 and Pin 7 to facilitate flexible circuit layout and heat dissipation.

Maximum Ratings

The maximum ratings for the 11DS5 are defined under the Design-Maximum system. Operating the tube beyond these limits may impair its performance and reduce its operational lifespan.

  • Plate Voltage: 275 V maximum
  • Grid-No.2 (Screen-Grid) Voltage: 275 V maximum
  • Grid-No.1 (Control-Grid) Voltage (Positive-bias value): 0 V maximum
  • Plate Dissipation: 9 W maximum
  • Grid-No.2 Input: 2.2 W maximum
  • Bulb Temperature (At hottest point): 250 C maximum

Typical Operation and Electrical Characteristics

The 11DS5 is operated as a Class A1 amplifier. It can be configured using either cathode-bias or fixed-bias topologies. The typical operating parameters under these conditions are detailed below:

ParameterCathode-Bias (Option 1)Cathode-Bias (Option 2)Fixed-Bias (Option 1)Fixed-Bias (Option 2)Unit
Plate Supply Voltage200250200250V
Grid-No.2 Supply Voltage200200200200V
Grid-No.1 Voltage-7.5-8.5V
Cathode-Bias Resistor180270̉
Peak AF Grid-No.1 Voltage7.59.27.58.5V
Zero-Signal Plate Current34.5273529mA
Maximum-Signal Plate Current32.5253632mA
Zero-Signal Grid-No.2 Current3.5333mA
Maximum-Signal Grid-No.2 Current99910mA
Plate Resistance (Approx.)28,00028,00028,00028,000̉
Transconductance6,0005,8006,0005,800̉mhos
Load Resistance6,0008,0006,0008,000̉
Total Harmonic Distortion1010910%
Maximum-Signal Power Output2.83.633.8W

Interelectrode Capacitances and Circuit Limits

Direct Interelectrode Capacitances

These approximate values are measured without an external shield:

  • Grid No.1 to Plate: 0.19 pF
  • Grid No.1 to Cathode, Heater, Grid No.2, and Grid No.3: 9.5 pF
  • Plate to Cathode, Heater, Grid No.2, and Grid No.3: 6.3 pF

Maximum Circuit Values

To maintain thermal stability and prevent grid emission issues, the maximum resistance in the grid-No.1 circuit must not exceed the following values:

  • For Fixed-Bias Operation: 0.1 M̉ maximum
  • For Cathode-Bias Operation: 1 M̉ maximum

Technical Summary

The 11DS5 is a miniature, 7-pin beam power tube optimized for audio output stages in consumer electronics. It features an 11.2 V, 0.45 A heater with a controlled 11-second warm-up time, making it highly compatible with series-string heater configurations. With a maximum plate dissipation rating of 9 W and a maximum power output of 3.8 W under typical Class A1 fixed-bias conditions, the 11DS5 provides a robust and efficient solution for compact audio amplification designs.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base
7BZ
Socket code
-
Base pins
7
Nominal heater voltage
11.2 V
Nominal heater current
450 mA
Parallel heater voltage
-
Parallel heater current
-
Series capable
No

7BZ - Terminal pinout

Electrical assignments shared by every tube using this base designation.

TerminalSectionConnectionEvidence
PIN1Pin 1AG1 — Control GridVerified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN2Pin 2AG3 — Suppressor GridGroup BZ2Verified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN2Pin 2AK — CathodeGroup BZ2Verified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN3Pin 3—H — HeaterVerified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN4Pin 4—H — HeaterVerified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN5Pin 5AP — Plate (Anode)Verified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN6Pin 6AG2 — Screen GridVerified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

PIN7Pin 7AG1 — Control GridVerified

Tung-Sol 6AQ5/6AQ5A 7BZ basing; manufacturer pinout

Section ratings

1 physical section, each with unique specifications.

Section 1

Beam Power

X-ray radiationInterelectrode capacitances
Plate resistance
28000 Ω
Transconductance
0.0058 S
Max plate voltage
275 V
Max screen voltage
275 V
Max plate dissipation
9 W
Max screen dissipation
2.2 W

Inherited from explicitly referenced parent type 6DS5; supplied sheet changes heater rating.

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

Beam Power

Capacitance

  • Grid-to-plate capacitance

    0.19 pF

    Inherited from explicitly referenced 6DS5 parent type.

  • Input capacitance

    9.5 pF

    Inherited from explicitly referenced 6DS5 parent type.

  • Output capacitance

    6.3 pF

    Inherited from explicitly referenced 6DS5 parent type.

Other

  • Plate supply voltage

    250 V

    ClassA1 Inherited from explicitly referenced 6DS5 parent type.

  • Screen voltage

    200 V

    ClassA1 Inherited from explicitly referenced 6DS5 parent type.

  • Zero-signal plate current

    27 mA

    ClassA1 Inherited from explicitly referenced 6DS5 parent type.

  • Maximum-signal power output

    3.6 W

    ClassA1 Inherited from explicitly referenced 6DS5 parent type.

Data set 02

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Capacitance

  • Grid No.1 to Plate

    0.19 pF

  • Grid No.1 to other electrodes

    9.6 pF

  • Plate to other electrodes

    6.3 pF

Other

  • Plate voltage

    250 V

    ClassA

  • Screen-grid voltage

    250 V

    ClassA

  • Plate current

    35 mA

    ClassA

  • Load resistance

    5000 ohm

    ClassA