25DQ6A

High-perveance beam-power pentode designed for efficient television horizontal-deflection amplifier circuits with controlled warm-up and high pulse ratings.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 6AM
Socket code: -
Base pins: 7
Nominal heater: 25 V / 300 mA

Description

The 25DQ6A is a high-perveance beam power pentode designed for high-efficiency horizontal-deflection amplifier circuits in television receivers, with controlled heater warm-up and high pulse ratings.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 6AM
Socket code: -
Base pins: 7
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

6AM - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Pin 1	—	NC May be omitted on some physical base variants	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN2Pin 2	—	H — Heater	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN3Pin 3	—	NC	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN4Pin 4	A	G2 — Screen Grid	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN5Pin 5	A	G1 — Control Grid	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN7Pin 7	—	H — Heater	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN8Pin 8	A	BP — Beam-Forming PlateGroup AM8	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
PIN8Pin 8	A	K — CathodeGroup AM8	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view
CAP1Top cap	A	P — Plate (Anode)	Verified 6AM manufacturer basing; 12DQ6A Tung-Sol, 6BQ6GT Sylvania/Tung-Sol; bottom view

Section ratings

1 physical section, each with unique specifications.

Section 1

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 20000 Ω
Transconductance: 0.0066 S
Max plate voltage: 700 V
Max screen voltage: 200 V
Max plate dissipation: 15 W
Max screen dissipation: 3 W
Max cathode current: 140 mA

Horizontal-deflection beam power pentode; 6000 V positive pulse and 1375 V negative pulse ratings.

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

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
Maximum peak positive pulse plate voltage
6000 V
HorizontalDeflection
Maximum peak negative pulse plate voltage
1375 V
HorizontalDeflection
Maximum peak cathode current
440 mA
HorizontalDeflection
Maximum grid 2 input
3 W
HorizontalDeflection
Plate voltage
250 V
ClassA
Screen voltage
150 V
ClassA
Grid 1 voltage
-22.5 V
ClassA

Characteristic

Heater warm-up time
11 s
ControlledWarmup
Plate resistance
20000 ohm
ClassA
Transconductance
6600 uS
ClassA
Plate current
75 mA
ClassA
Grid 2 current
2.4 mA
ClassA
Grid 1 cutoff voltage
-46 V
ClassA
Grid-2-to-grid-1 mu factor
4.1
ClassA

Capacitance

Grid 1 to plate
0.55 pF
Direct interelectrode capacitance
Input capacitance
15 pF
Direct interelectrode capacitance
Output capacitance
7 pF
Direct interelectrode capacitance

Data set 02

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
25 V
TypicalOperation
Heater current
300 mA
TypicalOperation
Maximum DC plate voltage including boost
700 V
WholeTube
Maximum positive pulse plate voltage
6000 V
HorizontalDeflection
Maximum negative pulse plate voltage
1375 V
HorizontalDeflection
Maximum DC cathode current
140 mA
WholeTube
Maximum peak cathode current
440 mA
WholeTube
Plate resistance
20000 ohm
ClassA1
Transconductance
6600 µS
ClassA1
Plate current
75 mA
ClassA1

Characteristic

Grid 1-to-plate capacitance
0.55 pF
WholeTube
Input capacitance
15 pF
WholeTube
Output capacitance
7 pF
WholeTube