6HJ5

Beam Tetrode — Compactron

Known Equivalents & Substitutes

21HJ530HJ5

Electrical Specifications

Section 1 — Beam Tetrode

Absolute Maximum

Anode Voltage (max)DC Plate Supply Voltage (max)770V

Peak Anode Voltage (max)Peak Positive Plate Voltage7,000V

Screen Voltage (max)Screen Voltage (max)220V

Anode Dissipation (max)Plate Dissipation (max)24W

Screen Dissipation (max)Screen Dissipation (max)6W

Cathode Current (max)Average Cathode Current (max)280mA

Heater-to-Cathode Voltage (max)Heater-Cathode Voltage (max)200V

Max Grid ResistorGrid No.1 Circuit Resistance (max)1MΩ

Typical Operating

Anode Voltage (typical)Plate Voltage135V

Grid 1 Bias VoltageGrid No.1 Voltage-22V

Screen VoltageScreen Voltage135V

Anode CurrentPlate Current80mA

Screen CurrentScreen Current5.5

Section 2 — Triode Strapped

Typical Operating

Anode Voltage (typical)Plate Voltage135V

Grid 1 Bias VoltageGrid No.1 Voltage-22V

Amplification Factor (μ)Amplification Factor4.2—

Heater

Heater VoltageHeater Voltage6.3V

Heater CurrentHeater Current2.25A

Notes

21HJ5 (21.5V/0.6A heater) and 30HJ5 (30V/0.45A heater) are heater-voltage variants, identical except for heater characteristics.
Pins 6 and 8 are internal connections marked 'Do Not Use' — socket clips for these pins should be omitted to improve insulation.
Grid No.1 and Grid No.2 each have dual base pins (3+11 and 5+9 respectively) for improved cooling. Grid No.3 (beam plates) also has dual pins (4+10).
An adequate bias resistor or other means is required to protect the tube in the absence of excitation.
Originally designed for TV horizontal deflection with peak plate voltages up to 7000V, but widely adopted by DIY audio builders as a triode-connected output tube.

Pin Layout — Compactron

1Heater

2

References