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7027

Beam-power tube designed for high-fidelity Class-A and push-pull Class-AB1 audio amplification, with documented output reaching roughly 50 watts per pair.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7AC
Socket code: IO
Base pins: 8
Nominal heater: 6.3 V / 900 mA

Description

Beam-power tube for high-fidelity Class A and push-pull Class AB1 audio power amplification.

Socket description

International Octal

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7AC
Socket code: IO
Base pins: 8
Nominal heater voltage: 6.3 V
Nominal heater current: 900 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: 22500 Ω
Transconductance: 0.006 S
Max plate voltage: 500 V
Max screen voltage: 450 V
Max plate dissipation: 30 W
Max screen dissipation: 5 W
Max cathode current: 150 mA

A.F. beam pentode. Limiting-value unit typo Wa=30 V is interpreted semantically as 30 W.

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

1971 RCA HB3 Binder 3 of 7

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
6.3 V
Heater current
900 mA
Plate voltage
250 V
ClassA
Screen voltage
250 V
ClassA
Grid voltage
-14 V
ClassA
Plate current
72 mA
ClassA
Screen current
5 mA
ClassA
Push-pull plate voltage
450 V
ClassAB1;TwoTubes
Push-pull screen voltage
350 V
ClassAB1;TwoTubes
Maximum-signal power output
50 W
ClassAB1;PushPull;TwoTubes

Characteristic

Plate resistance
22500 ohm
ClassA
Transconductance
6000 uS
ClassA

Capacitance

Grid-to-plate capacitance
1.5 pF
Input capacitance
10 pF
Output capacitance
7.5 pF

Data set 02

199X JJ

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Typical Plate Voltage
250 V
Typical Screen Voltage
250 V
TypicalControlGridVoltage
-14 V
Typical Plate Current
72 mA
Typical Screen Current
5 mA
LoadResistanceSingle
22500 ohm
ClassA1;OneTube
PowerOutputSingle
6.5 W
ClassA1;OneTube
PlateToPlateLoadResistance
5000 ohm
PushPull;ClassA1;TwoTubes
PowerOutputPushPull
17.5 W
PushPull;ClassA1;TwoTubes

Characteristic

GridCapacitance
12.5 pF
Plate Capacitance
10 pF
PlateGridCapacitance
3 pF

Data set 03

2026 JJ Electronic

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Uf
6.3 V
Published value
If
900 mA
Published value
Ua
250
Published value
Ug2
250
Published value
Ug1
-14
Published value
Ia
72
Published value
Ra
22.5
Published value
N
6.5
Published value
Triode Pentode cg1
12.5 pF
Published value
Ua
450
Published value
Ug2
450
Published value
Wa
30
Published value