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Power - Triode (over 1000V 100W) ·Triode

3CX3000A7

Very high-mu ceramic power triode designed for grounded-grid RF amplification and also usable in high-power audio service. Forced-air cooled, with multi-kilowatt dissipation and published operation extending into VHF.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: -
Socket code: -
Base pins: -
Nominal heater: 7.5 V / 51.5 A

Description

High-mu forced-air ceramic-metal power triode, coaxial-base version.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: -
Socket code: -
Base pins: -
Nominal heater voltage: 7.5 V
Nominal heater current: 51.5 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

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

Triode

X-ray radiationInterelectrode capacitances

Amplification factor: 160
Max plate voltage: 5000 V
Max plate dissipation: 4000 W
Max grid dissipation: 225 W
Max cathode current: 2.5 A

Maximum ratings promoted from the printed service-rating tables; typical operating values are preserved as parameters.

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

1962 Eimac

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Maximum plate voltage
5000 V
Maximum plate/cathode current
2.5 A
Maximum plate dissipation
4000 W
Maximum grid dissipation
225 W

Data set 02

1965 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Grounded-Filament Input Capacitance
38 pF
Grounded-Filament Output Capacitance
0.6 pF
Grounded-Filament Grid-Plate Capacitance
24 pF
Grounded-Grid Input Capacitance
38 pF
Grounded-Grid Output Capacitance
24 pF
Grounded-Grid Plate-Cathode Capacitance
0.6 pF
Frequency Maximum
110 MHz
RF Plate Voltage Maximum
5000 V
RF Plate Current Maximum
2.5 A
Typical Power Gain Minimum
20 ratio
Forced-Air Cooling Required
1 boolean

Data set 03

1975 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Grounded-Filament Input Capacitance
38 pF
Grounded-Filament Output Capacitance
0.6 pF
Grounded-Filament Grid-Plate Capacitance
24 pF
Grounded-Grid Input Capacitance
38 pF
Grounded-Grid Output Capacitance
24 pF
Grounded-Grid Plate-Cathode Capacitance
0.6 pF
Frequency Maximum
110 MHz
RF Plate Voltage Maximum
5000 V
RF Plate Current Maximum
2.5 A

Characteristic

Typical Power Gain Minimum
20 ratio
GroundedGrid

Data set 04

1976 Eimac Tube Manual

Published operating points and test conditions from this source.

SECTION 1

Triode

Other

Grounded-Filament Input Capacitance
38 pF
Grounded-Filament Output Capacitance
0.6 pF
Grounded-Filament Grid-Plate Capacitance
24 pF
Grounded-Grid Input Capacitance
38 pF
Grounded-Grid Output Capacitance
24 pF
Grounded-Grid Plate-Cathode Capacitance
0.6 pF
Frequency Maximum
110 MHz
RF Plate Voltage Maximum
5000 V
RF Plate Current Maximum
2.5 A

Characteristic

Typical Power Gain Minimum
20 ratio
GroundedGrid

Data set 05

199X Svetlana

Published operating points and test conditions from this source.

SECTION 1

Triode

Characteristics

Current @
7.5 V
class AB, or class B RF or audio amplifiers.
Input
38 pF
class AB, or class B RF or audio amplifiers.
Output
24 pF
class AB, or class B RF or audio amplifiers.
Feedback
0.6 pF
class AB, or class B RF or audio amplifiers.
Input
38 pF
class AB, or class B RF or audio amplifiers.
Output
0.6 pF
class AB, or class B RF or audio amplifiers.
Feedback
24 pF
class AB, or class B RF or audio amplifiers.
Maximum frequency for full ratings (CW)
110 MHz
class AB, or class B RF or audio amplifiers.

Other

DC plate voltage
5000 V
Maximum Ratings
DC plate current
2.5 A
Maximum Ratings
Plate dissipation
4000 W
Maximum Ratings
Grid dissipation
225 W
Maximum Ratings
(Frequencies to
30 MHz
Typical Operation
Plate Voltage 4000 4800
4800 V
Typical Operation
Zero-signal plate current* 0.25 0.35
350 mA
Typical Operation
Single-tone plate current 2.00 1.68
2 A
Typical Operation
Grid bias 0 0
0 V
Typical Operation
Single-tone grid current* 0.61 0.46
600 mA
Typical Operation
Peak driving power 420 293
410 W
Typical Operation
Plate dissipation 2285 2275
2775 W
Typical Operation
Single-tone plate output power 6030 6000
7266 W
Typical Operation
Resonant load impedance 1210 1720
1425 Ohms
Typical Operation
Driving impedance 47.5 50.0
46.3 Ohms
Typical Operation
DC Plate voltage
5000 V
Maximum Ratings
DC Plate current
2.5 A
Maximum Ratings
Plate dissipation
4000 W
Maximum Ratings
Grid dissipation
225 W
Maximum Ratings
(Frequencies to
110 MHz
Typical operation
Plate voltage 3500
4800 V
Typical operation
Grid voltage -50
-60 V
Typical operation
Plate current 1.30
1.54 A
Typical operation
Grid current* 0.42
480 mA
Typical operation
Peak RF cathode voltage* 220
267 V
Typical operation
Calculated driving power* 310
435 W
Typical operation
Plate dissipation 985
1480 W
Typical operation
Useful output power 3300
5500 W
Typical operation
DC plate voltage
5000 V
Maximum Ratings (per tube)
DC plate current
2.5 A
Maximum Ratings (per tube)
Plate dissipation
3000 W
Maximum Ratings (per tube)
Grid dissipation
225 W
Maximum Ratings (per tube)
Plate voltage
4000 V
Typical Operation (two tubes, sinusoidal waveform)
Zero-signal plate current
500 mA
Typical Operation (two tubes, sinusoidal waveform)
Maximum-signal plate current
3.58 A
Typical Operation (two tubes, sinusoidal waveform)
Maximum-signal grid current
580 mA
Typical Operation (two tubes, sinusoidal waveform)
Peak AF grid voltage
190 V
Typical Operation (two tubes, sinusoidal waveform)
Peak driving power
115 W
Typical Operation (two tubes, sinusoidal waveform)
Maximum-signal plate dissipation
1850 W
Typical Operation (two tubes, sinusoidal waveform)
Plate output power
10500 W
Typical Operation (two tubes, sinusoidal waveform)
Load resistance (plate-to-plate)
2720 Ohms
Typical Operation (two tubes, sinusoidal waveform)
Filament current at
7.5 V
Typical Operation (two tubes, sinusoidal waveform)
Input 30.0
45 pF
Typical Operation (two tubes, sinusoidal waveform)
Output 20.0
28 pF
Typical Operation (two tubes, sinusoidal waveform)
Feedback —
1 pF
Typical Operation (two tubes, sinusoidal waveform)
Input 30.0
45 pF
Typical Operation (two tubes, sinusoidal waveform)
Output
1 pF
Typical Operation (two tubes, sinusoidal waveform)
Feedback 20.0
28 pF
Typical Operation (two tubes, sinusoidal waveform)
Zero-Bias plate current (Eb =
5000 V
Typical Operation (two tubes, sinusoidal waveform)
Cut-off bias (Eb =
5000 V
Typical Operation (two tubes, sinusoidal waveform)
below
250 ˚C
Typical Operation (two tubes, sinusoidal waveform)
maintain these temperatures below
225 ˚C
Typical Operation (two tubes, sinusoidal waveform)
with an inlet-air temperature of
40 ˚C
Typical Operation (two tubes, sinusoidal waveform)
tabulated. At frequencies above
30 MHz
Typical Operation (two tubes, sinusoidal waveform)