10Z10 — Compactron Gated-Beam Discriminator and Power Pentode

The 10Z10 is a multi-unit vacuum tube of the compactron design, housing two independent electrical systems within a single T-9 glass envelope: a gated-beam discriminator and a beam power pentode. It is designed primarily for use in television and FM radio receivers, where the gated-beam discriminator serves as a combined limiter and discriminator, and the pentode section functions as an audio power-output amplifier.

The 10Z10 is identical to the 6Z10 (also designated 6Z10/6J10) and the 13Z10 (also designated 13Z10/13J10) except for its heater characteristics and ratings. It requires a standard 12-contact duodecar socket for operation.

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Heater Characteristics and Operation

The 10Z10 features a coated unipotential cathode structure with heater ratings optimized for series-string or specific parallel power arrangements.

Heater-Cathode Voltage Ratings

To ensure insulation integrity between the heater and the separate cathodes of each section, the following maximum voltage limits must be observed:

• Heater Negative with Respect to Cathode: 200 V (Total DC and Peak)
• Heater Positive with Respect to Cathode: 100 V (DC), 200 V (Total DC and Peak)

Heater Design Considerations

The nominal heater voltage of 10.0 V is specified for a "bogey" tube drawing exactly 0.6 amperes. Equipment designers must ensure that the heater current is centered at this bogey value, with supply variations restricted to keep the current within the specified 0.04 A tolerance.

The average heater warm-up time of 11 seconds is defined under specific test conditions: the time required for the voltage across the heater to reach 80% of its bogey value (8.0 V) when 4 times the bogey voltage (40.0 V) is applied to a circuit consisting of the heater in series with a resistance equal to 3 times the bogey heater voltage divided by the bogey heater current.

• Bogey Heater Resistance Calculation: $\text{Resistance} = \frac{\text{Heater Voltage}}{\text{Heater Current}} = \frac{10.0\text{ V}}{0.6\text{ A}} \approx 16.67\ \Omega$
• Series Test Resistance Calculation: $\text{Series Resistance} = 3 \times 16.67\ \Omega = 50.0\ \Omega$
• Heater Power Consumption Calculation: $\text{Power} = \text{Heater Voltage} \times \text{Heater Current} = 10.0\text{ V} \times 0.6\text{ A} = 6.0\text{ W}$

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Physical Specifications and Pinout

The 10Z10 utilizes the compactron T-9 construction, which provides a compact physical profile with excellent mechanical stability.

Physical Dimensions

• Outline Designation: 9-58
• Maximum Diameter: 1.188 inches
• Maximum Seated Height: 2.000 inches
• Maximum Overall Height: 2.375 inches
• Mounting Position: Any

Pin Connections (12BT Basing)

The tube uses a 12-pin button base (E12-70). Viewed from the underside, the pin connections are assigned as follows:

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Direct Interelectrode Capacitances

The internal shielding and electrode geometry of the 10Z10 minimize capacitive coupling between the two independent sections. The capacitances are specified without an external shield:

Gated-Beam Discriminator Section (Section 1)

• Grid No. 1 to Grid No. 3: 0.009 pF
• Grid No. 1 to All (Cathode, Heater, Grid No. 2, Grid No. 3, Plate, and Internal Shield): 4.4 pF
• Grid No. 3 to All (Cathode, Heater, Grid No. 1, Grid No. 2, Plate, and Internal Shield): 3.2 pF

Pentode Section (Section 2)

• Grid No. 1 to Plate: 0.22 pF
• Input (Grid No. 1 to Cathode, Heater, Grid No. 2, and Grid No. 3): 11 pF
• Output (Plate to Cathode, Heater, Grid No. 2, and Grid No. 3): 7.5 pF

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Gated-Beam Discriminator (Section 1)

The gated-beam discriminator section is designed to operate as a combined limiter and discriminator in FM and television sound systems. It features high sensitivity and excellent AM rejection capabilities.

Maximum Ratings (Design-Maximum Values)

• Plate Supply Voltage: 330 V
• Grid-No. 2 (Accelerator) Voltage: 330 V
• Grid-No. 1 Voltage, Peak Positive Value: 60 V
• Average Cathode Current: 13 mA

Characteristics and Typical Operation

The gated-beam section can be operated under different circuit configurations depending on whether the accelerator (Grid No. 2) is fed from a direct voltage source or through a series dropping resistor.

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Pentode Section (Section 2)

The pentode section of the 10Z10 is a beam power unit designed for Class A1 audio power amplification, capable of delivering sufficient output power to drive a loudspeaker directly.

Maximum Ratings (Design-Maximum Values)

• Plate Voltage: 275 V
• Grid-No. 2 (Screen-Grid) Voltage: 275 V
• Plate Dissipation: 10 W
• Grid-No. 2 Input (Screen Dissipation): 2.0 W

Maximum Circuit Values

• Grid-No. 1 Circuit Resistance (Fixed Bias): 0.25 M̤
• Grid-No. 1 Circuit Resistance (Cathode Bias): 0.5 M̤

Typical Class A1 Operating Conditions and Performance

At a typical operating point of 250 V on both the plate and screen grid, the pentode section exhibits the following characteristics:

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Technical Summary

The 10Z10 is a versatile compactron double-unit tube combining a gated-beam discriminator and a beam power pentode in a single T-9 glass envelope. Operating with a 10.0 V, 0.6 A heater, it is designed for space-saving and cost-effective implementation in FM and television receiver audio stages.

The gated-beam section provides efficient limiting and FM demodulation with a plate supply rating of up to 330 V, while the power pentode section delivers up to 4.2 W of audio output power under typical Class A1 conditions with a plate dissipation limit of 10 W. By integrating these two distinct functions, the 10Z10 simplifies receiver circuitry while maintaining high performance.