Data set 01
1950 Sylvania
Published operating points and test conditions from this source.
SECTION 1
Beam Power
Application
Service
Audio power output
Power - Beam (NOT sweep) ·BeamPower
25C6G
Beam-power amplifier designed for relatively low-voltage output service, with a 12.5-watt plate-dissipation rating and published Class-A operation.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- 7AC
- Socket code
- -
- Base pins
- 7
- Nominal heater
- 25 V / 300 mA
Description
Beam power amplifier tube for low-voltage output service.
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- 7AC
- Socket code
- -
- Base pins
- 7
- Nominal heater voltage
- 25 V
- Nominal heater current
- 300 mA
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
7AC - Terminal pinout
Electrical assignments shared by every tube using this base designation.
| Terminal | Section | Connection | Evidence |
|---|---|---|---|
| PIN1Pin 1 | — | NC | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN2Pin 2 | — | H — Heater | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN3Pin 3 | A | P — Plate (Anode) | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN4Pin 4 | A | G2 — Screen Grid | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN5Pin 5 | A | G1 — Control Grid | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN7Pin 7 | — | H — Heater | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN8Pin 8 | A | BP — Beam-Forming PlateGroup AC8 | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
| PIN8Pin 8 | A | K — CathodeGroup AC8 | Verified 12L6GT/25L6GT manufacturer basing, 7AC |
Section ratings
1 physical section, each with unique specifications.
Section 1
Beam Power
X-ray radiationInterelectrode capacitances
- Plate resistance
- 18300 Ω
- Transconductance
- 0.0071 S
- Max plate voltage
- 200 V
- Max screen voltage
- 135 V
- Max plate dissipation
- 12.5 W
- Max screen dissipation
- 1.75 W
Beam-power amplifier section.
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 02
195X General Electric Essential Characteristics
Published operating points and test conditions from this source.
SECTION 1
Beam Power
Other
Plate voltage
200 V
ClassA
Screen-grid voltage
135 V
ClassA
Grid voltage
-14 V
ClassA
Plate current
61 mA
ClassA
Screen-grid current
2.2 mA
ClassA
Load resistance
2600 ohm
ClassA
Power output
6 W
ClassA
Data set 03
1961 Tung Sol
Published operating points and test conditions from this source.
SECTION 1
Beam Power
Other
Heater voltage
25 V
Nominal
Heater current
300 mA
Nominal
Plate voltage
135 V
ClassA; OperatingPoint1
Plate voltage
200 V
ClassA; OperatingPoint2
Screen voltage
135 V
ClassA; OperatingPoint1
Screen voltage
135 V
ClassA; OperatingPoint2
Control-grid voltage
-13.5 V
ClassA; OperatingPoint1
Control-grid voltage
-14 V
ClassA; OperatingPoint2
Load resistance
2000 ohm
ClassA; OperatingPoint1
Load resistance
2600 ohm
ClassA; OperatingPoint2
Power output
3.6 W
ClassA; OperatingPoint1
Power output
6 W
ClassA; OperatingPoint2
Total harmonic distortion
10 %
ClassA; OperatingPoint1
Total harmonic distortion
10 %
ClassA; OperatingPoint2
Characteristic
Zero-signal plate current
58 mA
ClassA; OperatingPoint1
Zero-signal plate current
61 mA
ClassA; OperatingPoint2
Zero-signal screen current
3.5 mA
ClassA; OperatingPoint1
Zero-signal screen current
2.2 mA
ClassA; OperatingPoint2
Plate resistance
9300 ohm
ClassA; OperatingPoint1
Plate resistance
18300 ohm
ClassA; OperatingPoint2
Transconductance
7000 uS
ClassA; OperatingPoint1
Transconductance
7100 uS
ClassA; OperatingPoint2