13V10 — Compactron Dissimilar Double Pentode
The 13V10 is a multi-unit vacuum tube of the compactron (duodecar) design, combining a high-power beam pentode and a sharp-cutoff, dual-control pentode in a single glass envelope. It is specifically designed for television receiver applications, where the beam power unit serves as the audio-frequency output amplifier and the sharp-cutoff pentode functions as an FM detector.
Overview
The 13V10 is a multi-electrode vacuum tube containing two highly dissimilar pentode sections within a single T-9 glass envelope. This compactron configuration is engineered to consolidate two distinct stages of a television receiver's audio system:
- Section 1 (Beam Power Unit): A power pentode designed for Class A1 audio-frequency power amplification, capable of driving the speaker output stage.
- Section 2 (Pentode Unit): A sharp-cutoff, dual-control pentode optimized for use as an FM detector or a low-level Class A1 amplifier.
The tube features a 12-pin button base (E12-70) and is designed to operate in any mounting position. It utilizes a series-string heater rated at 13.2 V with a controlled warm-up time, making it suitable for series-connected heater circuits in television designs.
Construction, Heater, and Base Configuration
The 13V10 is constructed using a T-9 glass envelope with a 12-pin button base (E12-70), requiring a standard duodecar 12-contact socket. The physical dimensions are tightly specified to fit compact chassis layouts:
Heater Characteristics
The cathodes of both sections are coated unipotential types. The heater is designed for reliable operation in series-string or parallel configurations, with a controlled warm-up characteristic to minimize voltage surges in series strings.
Terminal Connections and Basing Diagram (EIA 12EZ)
The duodecar base provides separate connections for the electrodes of both sections, along with an internal shield associated with Section 2:
- Pin 1: Heater
- Pin 2: Cathode and Internal Shield (Section 2)
- Pin 3: Grid Number 1 (Section 2)
- Pin 4: No Connection
- Pin 5: Grid Number 3 (Suppressor) (Section 2)
- Pin 6: Grid Number 2 (Screen) (Section 2)
- Pin 7: Plate (Section 2)
- Pin 8: Grid Number 1 (Section 1)
- Pin 9: Cathode and Beam Plates (Section 1)
- Pin 10: Grid Number 2 (Screen) (Section 1)
- Pin 11: Plate (Section 1)
- Pin 12: Heater
Section 1: Beam Power Unit (Class A1 Amplifier)
Section 1 is a power pentode (beam power unit) optimized for Class A1 audio amplification. It features high transconductance and moderate power output at relatively low plate and screen voltages.
Maximum Ratings (Design-Maximum Values)
These ratings represent the absolute limits for safe and reliable operation of the beam power unit:
- Plate Voltage: 165 V
- Grid-No. 2 (Screen-Grid) Voltage: 150 V
- Plate Dissipation: 6.5 W
- Grid-No. 2 Input: 1.8 W
- DC Cathode Current: 65 mA
- Grid-No. 1 Circuit Resistance:
- With Fixed Bias: 0.25 MΩ
- With Cathode Bias: 0.5 MΩ
Typical Operating Conditions and Characteristics
Under typical Class A1 operating conditions, Section 1 provides a power output of 1.5 watts with low distortion:
Section 2: Sharp-Cutoff Pentode Unit
Section 2 is a sharp-cutoff, dual-control pentode designed primarily for FM detection (such as quadrature detection) and low-level Class A1 voltage amplification.
Class A1 Amplifier Characteristics
When operated as a standard Class A1 amplifier, Section 2 exhibits the following characteristics:
- Plate Supply Voltage: 150 V
- Grid-No. 3 (Suppressor-Grid) Voltage: 0 V
- Grid-No. 2 (Screen-Grid) Supply Voltage: 100 V
- Cathode-Bias Resistor: 560 Ω
- Plate Resistance (Approx.): 0.15 MΩ
- Grid-No. 1 to Plate Transconductance: 1,000 mhos
- Grid-No. 3 to Plate Transconductance: 400 mhos
- Plate Current: 1.3 mA
- Grid-No. 2 Current: 2.0 mA
- Grid-No. 1 Voltage (Approx.) for plate current of 10 A: -4.5 V
- Grid-No. 3 Voltage (Approx.) for plate current of 10 A: -4.5 V
FM Detector Maximum Ratings (Design-Maximum Values)
When utilized in FM detector service, Section 2 can withstand higher supply voltages:
- Plate Voltage: 330 V
- Grid-No. 3 Voltage: 28 V
- Grid-No. 2 Supply Voltage: 330 V
- Grid-No. 1 (Control-Grid) Voltage (Positive-bias value): 0 V
- Plate Dissipation: 1.7 W
- Grid-No. 2 Input:
- For Grid-No. 2 voltages up to 165 V: 1.1 W
- For Grid-No. 2 voltages between 165 V and 330 V: Regulated by the screen rating chart (maximum dissipation decreases as voltage increases)
Interelectrode Capacitances and Coupling
Because the 13V10 houses two highly dissimilar pentode sections within a single envelope, internal shielding and physical separation are critical to prevent unwanted coupling. The capacitances measured without an external shield are:
Section 1 (Beam Power Unit)
- Grid-No. 1 to Plate (1g1 to 1p): 0.20 pF
- Input (1g1 to h + 1k + 2k + 1g2 + b.p. + i.s.): 10 pF
- Output (1p to h + 1k + 2k + 1g2 + b.p. + i.s.): 10 pF
Section 2 (Sharp-Cutoff Pentode)
- Grid-No. 1 to Plate (2g1 to 2p): 0.04 pF
- Grid-No. 3 to Plate (2g3 to 2p): 3.0 pF
- Grid-No. 1 to All Except Plate (2g1 to h + 2k + 2g2 + 2g3 + i.s.): 6.5 pF
- Grid-No. 3 to All (2g3 to h + 2k + 2g1 + 2g2 + 2p + i.s.): 8.0 pF
- Grid-No. 1 to Grid-No. 3 (2g1 to 2g3): 0.15 pF
Inter-Section Coupling
- Plate (Section 1) to Plate (Section 2) (1p to 2p): 0.14 pF
The low plate-to-plate coupling capacitance (0.14 pF) demonstrates the effectiveness of the internal shielding, ensuring that the high-amplitude audio signals in Section 1 do not interfere with the sensitive FM detection circuitry in Section 2.
Technical Summary
The 13V10 is a versatile compactron dissimilar double pentode designed to streamline television audio systems. By combining a 1.5-watt Class A1 beam power amplifier and a sharp-cutoff, dual-control pentode in a single T-9 envelope, it eliminates the need for separate detector and output tubes.
With its robust 13.2 V / 0.45 A series-string heater, controlled 11-second warm-up time, and excellent internal shielding, the 13V10 represents a highly integrated solution for mid-century television receiver designs.
