Power - Beam (NOT sweep) ·BeamPower-Pentode
17BF11A
Dual-pentode television tube with insufficient surviving source description in the available record to support a narrower functional classification.
- Sections
- 2
- Base
- 12EZ
- Socket code
- B12C
- Base pins
- 12
- Nominal heater
- 16.8 V / 450 mA
Description
17BF11A — Beam Pentode and Sharp-Cutoff Pentode
The 17BF11A is a multi-unit vacuum tube of Compactron construction containing a beam pentode and a sharp-cutoff pentode in a single envelope. Designed primarily for use in color television receivers, the tube is suited for applications such as audio power amplification and FM detection.
Overview and Designations
The 17BF11A is electrically and structurally identical to the 17BF11 except for its physical envelope, featuring a shorter bulb design. It integrates two distinct pentode sections—a beam power pentode and a sharp-cutoff pentode—within a single T-9 glass envelope. This multi-unit configuration is designed to reduce component count and space requirements in television chassis, where it can simultaneously perform audio power output and FM detector functions.
Physical Construction and Dimensions
The tube utilizes a Compactron T-9 construction with a glass envelope and a 12-pin button base. The physical dimensions of the device are specified as follows:
- Maximum Diameter: 1.188 inches
- Maximum Seated Height: 1.875 inches
- Maximum Overall Height: 2.250 inches
- Base Type: Button 12-Pin, E12-70
Pinout and Basing Arrangement
The 17BF11A uses the 12EZ basing diagram. The 12-pin layout provides independent connections for the electrodes of both sections, with the exception of the heater, which shares a pin with one of the control grids. Specifically, the heater is connected between Pin 12 and Pin 1, where Pin 1 also serves as the Grid No. 1 connection for Section 1.
The pin connections are assigned as follows:
- Pin 1: 1G1 (Grid No. 1, Section 1) / Heater Connection
- Pin 2: 2G2 (Grid No. 2, Section 2)
- Pin 3: NC (No Connection)
- Pin 4: 2G1 (Grid No. 1, Section 2)
- Pin 5: 2K (Cathode, Section 2)
- Pin 6: 2G3 (Grid No. 3, Section 2)
- Pin 7: 2P (Plate, Section 2)
- Pin 8: 1G3 (Grid No. 3, Section 1)
- Pin 9: 1K (Cathode, Section 1)
- Pin 10: 1G2 (Grid No. 2, Section 1)
- Pin 11: 1P (Plate, Section 1)
- Pin 12: H (Heater)
Typical Characteristics and Operating Conditions
The typical operating parameters and performance characteristics under specified conditions include the following values:
- Zero-Signal Screen Current: 3.0 mA
- Maximum Signal Screen Current: 9.0 mA
- Load Resistance: 3000 Ohms
- Total Harmonic Distortion (Approx.): 10%
- Maximum Signal Power Output: 2.4 Watts
These operating conditions reflect the performance of the power amplifier portion of the tube, delivering up to 2.4 watts of audio output power into a 3000-ohm load with approximately 10% total harmonic distortion.
Socket description
Duodecar 12-contact
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- 12EZ
- Socket code
- B12C
- Base pins
- 12
- Nominal heater voltage
- 16.8 V
- Nominal heater current
- 450 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
12EZ - Terminal pinout
Electrical assignments shared by every tube using this base designation.
| Terminal | Section | Connection | Evidence |
|---|---|---|---|
| PIN1Pin 1 | — | H — Heater | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN2Pin 2 | B | K — CathodeGroup EZ2 | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN2Pin 2 | B | SH — Internal ShieldGroup EZ2 | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN3Pin 3 | B | G1 — Control Grid | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN4Pin 4 | — | NC | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN5Pin 5 | B | G3 — Suppressor Grid | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN6Pin 6 | B | G2 — Screen Grid | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN7Pin 7 | B | P — Plate (Anode) | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN8Pin 8 | A | G1 — Control Grid | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN9Pin 9 | A | BP — Beam-Forming PlateGroup EZ9 | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN9Pin 9 | A | K — CathodeGroup EZ9 | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN10Pin 10 | A | G2 — Screen Grid | Verified GE 12AE10 terminal connections 12EZ, 1968 |
| PIN11Pin 11 | A | P — Plate (Anode) | Verified GE 12AE10 terminal connections 12EZ |
| PIN12Pin 12 | — | H — Heater | Verified GE 12AE10 terminal connections 12EZ |
Section ratings
2 physical sections, each with unique specifications.
Section 1
Pentode
- Max plate voltage
- 330 V
- Max screen voltage
- 330 V
- Max plate dissipation
- 1.7 W
- Max screen dissipation
- 1.1 W
Reference/equivalence-only source does not reproduce the referenced electrical ratings/characteristics; promoted values intentionally not inferred from external datasheets.
Section 2
Beam Power
- Max plate voltage
- 165 V
- Max screen voltage
- 150 V
- Max plate dissipation
- 6.5 W
- Max screen dissipation
- 1.8 W
Reference/equivalence-only source does not reproduce the referenced electrical ratings/characteristics; promoted values intentionally not inferred from external datasheets.
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.