Data set 01
1950 Sylvania
Published operating points and test conditions from this source.
SECTION 1
Pentode
Other
Peak positive plate voltage
2000 V
VerticalDeflection
Power - Pentode (NOT beam) ·Pentode
12CM6
Beam-power output tube intended for audio-frequency amplification in television and radio equipment, providing moderate output power from low-voltage receiving-tube supplies.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- B9A
- Base pins
- 9
- Nominal heater
- 12.6 V / 225 mA
Description
12CM6 — Beam Power Pentode
The 12CM6 is a miniature beam power pentode designed for use in color television receivers. It is specifically rated for service as an audio power amplifier or a vertical deflection amplifier. The 12CM6 belongs to a family of structurally identical tubes that includes the 5CM6 and 6CM6, differing only in their heater ratings.
Construction, Basing, and Physical Dimensions
The 12CM6 is constructed with a miniature T-6 1/2 glass envelope and utilizes a button 9-pin (E9-1) base. The tube's physical dimensions are as follows:
- Maximum Diameter: 0.875 inches
- Maximum Seated Height: 2.375 inches
- Maximum Overall Height: 2.625 inches
- Outline Designation: 6-3
The tube uses the 9CK basing arrangement, which provides the following pin connections:
- Pin 1: Grid No. 1 (Control Grid)
- Pin 2: No Connection
- Pin 3: Grid No. 1 (Control Grid)
- Pin 4: Heater
- Pin 5: Heater
- Pin 6: Grid No. 3 (Suppressor Grid) and Cathode (internally connected)
- Pin 7: Grid No. 2 (Screen Grid)
- Pin 8: No Connection
- Pin 9: Plate
Heater and Capacitance Characteristics
The 12CM6 is designed for series or parallel heater circuits, operating at a nominal heater voltage of 12.6 V and a heater current of 225 mA. Unlike its sister tube, the 5CM6, which has a controlled heater warm-up time of 11 seconds, the warm-up time for the 12CM6 is not specified.
Heater-Cathode Voltage Ratings
The insulation between the heater and cathode is rated to withstand the following maximum voltages:
- 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)
Direct Interelectrode Capacitances
The typical capacitances of the tube, measured without an external shield, are:
- Grid No. 1 to Plate: 0.7 pF
- Input (g1 to h + k + g2 + g3): 8.0 pF
- Output (p to h + k + g2 + g3): 8.5 pF
Class A1 Amplifier Ratings and Typical Operation
Under the Design Center Rating System, the maximum ratings for Class A1 amplifier service are:
- Maximum Plate Voltage: 315 V
- Maximum Plate Dissipation: 12 W
- Maximum Grid No. 2 Voltage: 285 V
- Maximum Grid No. 2 Dissipation: 2 W
- Maximum Grid No. 1 Circuit Resistance (Fixed Bias): 0.1 MΩ
- Maximum Grid No. 1 Circuit Resistance (Cathode Bias): 0.5 MΩ
Typical Operation (Triode Connection)
When operated with the screen grid (Grid No. 2) connected to the plate, the 12CM6 exhibits the following typical characteristics:
- Plate Voltage: 250 V
- Grid No. 1 Voltage: -12.5 V
- Zero Signal Plate Current: 49.5 mA
- Plate Resistance (Approximate): 1960 Ω
- Transconductance: 5000 µmhos
- Amplification Factor: 9.8
- Grid No. 1 Voltage for Cutoff (Ib = 0.5 mA): -37 V (Approximate)
Typical Operation (Single Tube Pentode Connection)
The 12CM6 can be operated as a single-tube pentode amplifier under several typical conditions:
| Parameter | Condition A | Condition B | Condition C |
|---|---|---|---|
| Plate Voltage | 180 V | 250 V | 315 V |
| Grid No. 2 Voltage | 180 V | 250 V | 225 V |
| Grid No. 1 Voltage | -8.5 V | -12.5 V | -13.0 V |
| Peak AF Grid No. 1 Voltage | 8.5 V | 12.5 V | 13.0 V |
| Zero Signal Plate Current | 29 mA | 45 mA | 34 mA |
| Maximum Signal Plate Current | 30 mA | 47 mA | 35 mA |
| Zero Signal Grid No. 2 Current | 3.0 mA | 4.5 mA | 2.2 mA |
| Maximum Signal Grid No. 2 Current | 4.0 mA | 7.0 mA | 6.0 mA |
| Plate Resistance (Approximate) | 50,000 Ω | 50,000 Ω | 80,000 Ω |
| Transconductance | 3700 µmhos | 4100 µmhos | 3750 µmhos |
| Load Resistance | 5500 Ω | 5000 Ω | 8500 Ω |
| Maximum Signal Power Output | 2.0 W | 4.5 W | 5.5 W |
| Total Harmonic Distortion | 8% | 8% | 12% |
| Grid No. 1 Voltage for Cutoff (Ib = 0.5 mA) | — | -37 V | — |
Typical Operation (Push-Pull Pentode Connection)
For higher power output, two 12CM6 tubes can be operated in a push-pull configuration:
| Parameter | Condition A | Condition B |
|---|---|---|
| Plate Voltage | 250 V | 285 V |
| Grid No. 2 Voltage | 250 V | 285 V |
| Grid No. 1 Voltage | -15 V | -19 V |
| Peak AF Grid No. 1 Voltage | 30 V | 38 V |
| Zero Signal Plate Current | 70 mA | 70 mA |
| Maximum Signal Plate Current | 90 mA | 92 mA |
| Zero Signal Grid No. 2 Current | 5 mA | 4 mA |
| Maximum Signal Grid No. 2 Current | 13 mA | 13.5 mA |
| Load Resistance (Plate-to-Plate) | 10,000 Ω | 8000 Ω |
| Maximum Signal Power Output | 10 W | 14 W |
| Total Harmonic Distortion | 5% | 3.5% |
Vertical Deflection Amplifier Service
When used as a vertical deflection amplifier in a 525-line, 30-frame television system, the 12CM6 is subject to specific pulsed ratings. The duty cycle of the voltage pulse must not exceed 15% of one horizontal scanning cycle.
The maximum ratings for vertical deflection service under both pentode and triode connections are:
| Rating | Pentode Connection | Triode Connection |
|---|---|---|
| Maximum Plate Voltage | 315 V | 315 V |
| Absolute Maximum Peak Positive Plate Voltage | 2000 V | 2000 V |
| Maximum Plate Dissipation | 8 W | 9 W |
| Maximum Grid No. 2 Voltage | 285 V | — |
| Maximum Grid No. 2 Dissipation | 1.75 W | — |
| Maximum Peak Negative Grid Voltage | 250 V | 250 V |
| Maximum Average Cathode Current | 40 mA | 40 mA |
| Maximum Peak Cathode Current | 120 mA | 120 mA |
| Maximum Grid No. 1 Circuit Resistance (Cathode Bias) | 2.2 MΩ | 2.2 MΩ |
In stages operating with grid-leak bias, designers must provide an adequate cathode bias resistor or other suitable protective means to prevent damage to the tube in the event that excitation is lost.
Technical Summary
The 12CM6 is a versatile miniature beam power pentode housed in a T-6 1/2 envelope with a 9-pin button base. It features a 12.6 V, 225 mA heater and shares its electrical characteristics and physical structure with the 5CM6 and 6CM6. Designed for color television applications, it serves effectively as either an audio power amplifier or a vertical deflection amplifier. In audio applications, a push-pull pair can deliver up to 14 W of output power with low distortion. In vertical deflection service, it is rated to handle peak positive plate pulses up to 2000 V, making it robust against the high-voltage transients typical of television sweep circuits.
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
- 12.6 V
- Nominal heater current
- 225 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
- Transconductance
- 0.0041 S
- Max plate voltage
- 315 V
- Max screen voltage
- 285 V
- Max plate dissipation
- 12 W
- Max screen dissipation
- 2 W
Published source values promoted where applicable.
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.