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811A

High-mu directly heated power triode for RF and Class B audio amplification. Its high amplification factor and roughly 65 W plate dissipation provide substantial power gain with modest drive in transmitting and audio-output applications.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 3G
Socket code: UX4
Base pins: 4
Nominal heater: 6.3 V / 4 A

Description

High-mu power triode for RF and Class-B power-amplifier service.

Socket description

Medium-shell UX 4-contact

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 3G
Socket code: UX4
Base pins: 4
Nominal heater voltage: 6.3 V
Nominal heater current: 4 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

3G - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1Pin 1	—	F — Filament Transcribed directly from EIA chart; independent cross-check not yet performed.	Unverified EIA Base Connections chart, page 127 (uploaded BaseCodeDataCharts_OCR), base 3G
PIN3Pin 3	A	G1 — Control Grid Transcribed directly from EIA chart; independent cross-check not yet performed.	Unverified EIA Base Connections chart, page 127 (uploaded BaseCodeDataCharts_OCR), base 3G
PIN4Pin 4	—	F — Filament Transcribed directly from EIA chart; independent cross-check not yet performed.	Unverified EIA Base Connections chart, page 127 (uploaded BaseCodeDataCharts_OCR), base 3G
CAP1Top cap	A	P — Plate (Anode) Transcribed directly from EIA chart; independent cross-check not yet performed.	Unverified EIA Base Connections chart, page 127 (uploaded BaseCodeDataCharts_OCR), base 3G

Section ratings

1 physical section, each with unique specifications.

Section 1

Triode

X-ray radiationInterelectrode capacitances

Amplification factor: 160
Max plate voltage: 1500 V
Max plate dissipation: 65 W
Max cathode current: 175 mA

Published ratings/characteristics promoted where unambiguous.

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

1950 General Electric Transmitting Types

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

HeaterOrFilamentVoltage
6.3 V
HeaterOrFilamentCurrent
4 A

Other

FrequencyForMaximumRatings
30 MHz
Maximum Signal Power Output
340 W
ClassB;TwoTubes

Data set 02

1956 RCA Transmitting Tubes

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Amplification Factor
160

Other

Maximum Plate Voltage
1500 V
Maximum Plate Dissipation
65 W
Maximum Cathode Current
175 mA
Full-Input Operating Frequency Maximum
30 MHz
Power Output
135 W
ClassC,RF
Typical Plate Voltage
1250 V
Representative published point
Typical Plate Current
125 mA
Representative published point

Data set 03

1963 Amperex Condensed

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Plate voltage
1250 V
RFPower
Plate current
140 mA
RFPower
Power output
135 W
RFPower
Grid voltage
-50 V
RFPower
Grid current
45 mA
RFPower
Maximum frequency
100 MHz
RFPower

Data set 04

1971 RCA HB3 Binder 6 of 7

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristic

Heater/filament voltage nominal
6.3 V
WholeTube
Heater/filament current nominal
4 A
WholeTube
Grid to filament
59 pF
Published source row
Plate to filament
7 pF
Published source row

Other

Voltage (AC or DC)
6 V
Published source row
Voltage (AC or DC) (value 2)
3 V
Published source row
Current
4 A
Published source row
DC PLATE VOLTAGE
1250 V
Published source row
DC PLATE VOLTAGE (value 2)
1500 V
Published source row
CURRENT
175 mA
Published source row
CURRENT (value 2)
175 mA
Published source row
MAX.-SIGNAL PLATE INPUT
165 W
Published source row
MAX.-SIGNAL PLATE INPUT (value 2)
235 W
Published source row
PLATE DISSIPATION°
45 W
Published source row
PLATE DISSIPATION° (value 2)
65 W
Published source row
DC Plate Voltage
750 V
Published source row
DC Plate Voltage (value 2)
1250 V
Published source row
DC Plate Voltage (value 3)
1000 V
Published source row
DC Plate Voltage (value 4)
1250 V
Published source row
DC Plate Voltage (value 5)
1500 V
Published source row
DC Grid Voltages
0 V
Published source row
DC Grid Voltages (value 2)
0 V
Published source row
DC Grid Voltages (value 3)
0 V
Published source row
DC Grid Voltages (value 4)
0 V
Published source row
DC Grid Voltages (value 5)
-4.5 V
Published source row
Voltage
197 V
Published source row
Voltage (value 2)
145 V
Published source row
Voltage (value 3)
185 V
Published source row
Voltage (value 4)
175 V
Published source row
Voltage (value 5)
170 V
Published source row
Current
32 mA
Published source row
Current (value 2)
50 mA
Published source row
Current (value 3)
44 mA
Published source row
Current (value 4)
54 mA
Published source row
Current (value 5)
32 mA
Published source row
Current
350 mA
Published source row
Current (value 2)
260 mA
Published source row
Current (value 3)
350 mA
Published source row
Current (value 4)
350 mA
Published source row
Current (value 5)
313 mA
Published source row
DC PLATE VOLTAGE
1000 V
Published source row
DC PLATE VOLTAGE (value 2)
1250 V
Published source row
DC GRID VOLTAGE
-200 V
Published source row
DC GRID VOLTAGE (value 2)
0 V
Published source row
DC PLATE CURRENT
125 mA
Published source row
DC PLATE CURRENT (value 2)
150 mA
Published source row
DC GRID CURRENT
50 mA
Published source row
DC GRID CURRENT (value 2)
50 mA
Published source row
PLATE INPUT
115 W
Published source row
PLATE INPUT (value 2)
175 W
Published source row
PLATE DISSIPATION
30 W
Published source row
PLATE DISSIPATION (value 2)
45 W
Published source row
DC Plate Voltage
1000 V
Published source row
DC Plate Voltage (value 2)
1250 V
Published source row
Peak RF Grid Voltage
150 V
Published source row
Peak RF Grid Voltage (value 2)
250 V
Published source row
DC Plate Current
115 mA
Published source row
DC Plate Current (value 2)
140 mA
Published source row
DC Grid Current (Approx.)
9 mA
Published source row
DC Grid Current (Approx.) (value 2)
45 mA
Published source row
DC Grid Current (Approx.) (value 3)
45 mA
Published source row
Power Output (Approx )
88 W
Published source row
Power Output (Approx ) (value 2)
135 W
Published source row
DC PLATE VOLTAGE
1250 V
Published source row
DC PLATE VOLTAGE (value 2)
1500 V
Published source row
DC GRID VOLTAGE
-200 V
Published source row
DC GRID VOLTAGE (value 2)
-200 V
Published source row
DC PLATE CURRENT
175 mA
Published source row
DC PLATE CURRENT (value 2)
175 mA
Published source row
Published electrical value
0 mA
Published source row
Published electrical value (value 2)
50 mA
Published source row
Published electrical value (value 3)
50 mA
Published source row
PLATE INPUT
175 W
Published source row
PLATE INPUT (value 2)
260 W
Published source row
PLATE DISSIPATION
45 W
Published source row
PLATE DISSIPATION (value 2)
65 W
Published source row
DC Plate Voltage
1250 V
Published source row
DC Plate Voltage (value 2)
1500 V
Published source row
Peak RF Grid Voltage
140 V
Published source row
Peak RF Grid Voltage (value 2)
175 V
Published source row
DC Plate Current
140 mA
Published source row
DC Plate Current (value 2)
173 mA
Published source row