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25L6GT

Glass-octal beam-power output tube for AC/DC radio receivers, explicitly related to the 50L6GT except for heater ratings.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: B7-7
Socket code: IO
Base pins: 7
Nominal heater: 25 V / 300 mA

Description

Glass octal beam-power output tube for AC/DC radio receivers; 25L6GT is explicitly identical to 50L6GT except for heater ratings.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: B7-7
Socket code: IO
Base pins: 7
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

B7-7 - 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

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 28000 Ω
Transconductance: 0.008 S
Max plate voltage: 200 V
Max screen voltage: 125 V
Max plate dissipation: 10 W
Max screen dissipation: 1.25 W

Class-A amplifier values promoted from the 200-V plate / 125-V screen published condition.

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 01

1948 Brimar Radio Valve Manual

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristic

HeaterOrFilamentVoltage
25 V
HeaterOrFilamentCurrent
300 mA

Other

Power Output
3.3 W
ClassA

Data set 02

1958 Brimar Radio Valve No 7

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Power output maximum published
4.3 W

Data set 03

195X General Electric Essential Characteristics

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Capacitance

Input capacitance
15 pF
Output capacitance
10 pF
Grid-to-plate capacitance
0.8 pF

Other

Plate voltage
200 V
ClassA
Screen-grid voltage
125 V
ClassA
Cathode resistor
180 ohm
ClassA
Plate current
46 mA
ClassA
Screen-grid current
2.2 mA
ClassA
Load resistance
4000 ohm
ClassA
Power output
3.8 W
ClassA
Plate voltage
110 V
ClassA;LowVoltage
Screen-grid voltage
110 V
ClassA;LowVoltage
Grid voltage
-7.5 V
ClassA;LowVoltage
Plate current
49 mA
ClassA;LowVoltage
Screen-grid current
4 mA
ClassA;LowVoltage
Load resistance
2000 ohm
ClassA;LowVoltage
Power output
2.1 W
ClassA;LowVoltage

Characteristic

Plate resistance
28000 ohm
ClassA;PlateVoltage=200V
Transconductance
8000 uS
ClassA;PlateVoltage=200V
Plate resistance
13000 ohm
ClassA;LowVoltage
Transconductance
8000 uS
ClassA;LowVoltage

Data set 04

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
110 V
ClassA; OperatingPoint1
Plate voltage
200 V
ClassA; OperatingPoint2
Screen voltage
110 V
ClassA; OperatingPoint1
Screen voltage
125 V
ClassA; OperatingPoint2
Load resistance
2000 ohm
ClassA; OperatingPoint1
Load resistance
4000 ohm
ClassA; OperatingPoint2
Power output
2.1 W
ClassA; OperatingPoint1
Power output
3.8 W
ClassA; OperatingPoint2
Total harmonic distortion
10 %
ClassA; OperatingPoint1
Total harmonic distortion
10 %
ClassA; OperatingPoint2

Characteristic

Plate resistance
13000 ohm
ClassA; OperatingPoint1
Plate resistance
28000 ohm
ClassA; OperatingPoint2
Transconductance
8000 uS
ClassA; OperatingPoint1
Transconductance
8000 uS
ClassA; OperatingPoint2

Data set 05

1965 Sylvania Electronic Tubes Vol3

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Capacitance

Grid-to-plate capacitance
0.8 pF
Input capacitance
15 pF
Output capacitance
9 pF

Other

Plate voltage
200 V
ClassA

Characteristics

Transconductance
9500 uS
ClassA
Plate resistance
30000 Ohm
ClassA

Data set 06

1965 Westinghouse Data Book

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristics

Heater Voltage
25 V
Heater Current
300 mA
Grid-Plate Capacitance
0.8 pF
Input Capacitance
15 pF
Output Capacitance
9 pF

Other

Maximum Plate Voltage
200 V
Maximum Plate Dissipation
10 W
Maximum Screen Voltage
125 V
Maximum Screen Dissipation
1.25 W
Plate Voltage
200 V
ClassA
Screen Voltage
110 V
ClassA
Grid Voltage
-8 V
ClassA
Zero-Signal Plate Current
50 mA
ClassA
Maximum-Signal Plate Current
55 mA
ClassA

Data set 07

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Maximum plate voltage
200 V
WholeTube
Maximum screen voltage
125 V
WholeTube
Maximum plate dissipation
10 W
WholeTube
Maximum screen dissipation
1.25 W
WholeTube
Plate voltage
110 V
ClassA1
Plate resistance
13000 ohm
ClassA1
Transconductance
8000 µS
ClassA1
Power output
2.1 W
ClassA1

Data set 08

1968 General Electric Co

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Plate Voltage
200 V
ClassA
Screen Voltage
125 V
ClassA

Characteristic

Zero-Signal Plate Current
46 mA
ClassA
Maximum-Signal Power Output
3.8 W
ClassA

Data set 09

1975 RCA RC30

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater Voltage (ac/dc) 25
50 V
Published in approved target datasheet entry
Heater Current 0.3
150 mA
Published in approved target datasheet entry
Plate Voitige
200 V
Published in approved target datasheet entry
Grid-No.2 (Screen-Grid) Voltage
125 V
Published in approved target datasheet entry
Plate Dissipation
10 W
Published in approved target datasheet entry
Grid-No.2 Input 1
-25 W
Published in approved target datasheet entry
Plate Supply Voltage 110
200 V
Published in approved target datasheet entry
Grid-No.2 Supply Voltage 110
125 V
Published in approved target datasheet entry
Peak AF Grid-No.l Voltage 7.5
8 V
Published in approved target datasheet entry
Maximum-Signal Plate Current 50
47 mA
Published in approved target datasheet entry
Zero-Signal Grid-No.2 Current 4
2.2 mA
Published in approved target datasheet entry
Maximum-Signal Grid-No.2 Current 10
8.5 mA
Published in approved target datasheet entry
Plate Resistance (Approx.) 13000
28000 ohm
Published in approved target datasheet entry
Transconduetance 3000
8000 µS
Published in approved target datasheet entry
Load Resistance 2000
4000 ohm
Published in approved target datasheet entry
Maximum-Signal Power Output 2.1
3.8 W
Published in approved target datasheet entry

Capacitance

Grid No.l to Cathode, Heater, Grid No.2, and Grid No.i
15 pF
Published in approved target datasheet entry
Plate to Cathode. Heater, Grid No.2, and Grid No.3
9.5 pF
Published in approved target datasheet entry