800 — Power Triode, UX4 | Tubeofile

800

Power Triode — DHT — UX4

RCA

Known Equivalents & Substitutes

VT-64CV2657

Similar Tubes (Not Drop-In Compatible)

RK30

Normally replaceable transmitting triode per Radiomuseum; slightly different characteristics

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Plate Voltage (max, CCS)1,250V

Anode Dissipation (max)Plate Dissipation (max)35W

Cathode Current (max)Max-Signal Plate Current (Class B AF, Va=1250V)160mA

Typical Operating

Anode Voltage (typical)Plate Voltage (typical, Class A-F)1,000V

Grid 1 Bias VoltageGrid Voltage (Class A-F, Va=1000V)-55V

Anode CurrentZero-Signal Plate Current (Class A-F, Va=1000V)28mA

Amplification Factor (μ)Amplification Factor15—

Output

Output PowerOutput Power (Class B AF push-pull 2 tubes, Va=1250V)106W

Load ImpedanceLoad Resistance (Class B AF, Va=1250V, plate to plate)21,000Ω

Capacitances

Grid-to-Plate CapacitanceGrid-to-Plate Capacitance2.5pF

Grid-to-Cathode CapacitanceGrid-to-Filament Capacitance2.8pF

Anode-to-Cathode CapacitancePlate-to-Filament Capacitance0.8pF

Noise / RF

Max Operating FrequencyMax Operating Frequency (full ratings)60MHz

Heater

Heater VoltageFilament Voltage7.5V

Heater CurrentFilament Current3.25A

Notes

DHT tube: the thoriated tungsten filament serves as the cathode; specified for AC or DC filament supply.
Both plate and grid connections are via top caps; base pins carry only filament.
Pa_max = 35W (CCS) for all services.
Class B AF push-pull (2 tubes): Va=750V, Vg=-55V, RL=6400 Ohm, Pout=90W; Va=1000V, Vg=-55V, RL=12500 Ohm, Pout=100W; Va=1250V, Vg=-70V, RL=21000 Ohm, Pout=106W.
Class B RF telephony (per tube, max mod. factor 1.0): Va=750V, Vg=-40V, Ia=45mA, Po=10W; Va=1000V, Vg=-55V, Ia=42mA, Po=14W.
Class C plate-modulated RF (per tube, max mod. factor 1.0): Va=750V, Vg=-150V, Ia=70mA, Po=35W; Va=1000V, Vg=-200V, Ia=70mA, Po=50W.
Class C key-down telegraphy (per tube): Va=750V, Vg=-100V, Ia=70mA, Po=35W; Va=1000V, Vg=-135V, Ia=70mA, Po=50W; Va=1250V, Vg=-175V, Ia=70mA, Po=65W.
Used in the first experimental radio-localization (radar) set designed by Ugo Tiberio in 1936 (100W output at 200 MHz).

Pin Layout — UX4

1Filament

2No Connection

3No Connection

4Filament

References