843

Power Triode — DHT — UY5

RCA

Known Equivalents & Substitutes

VT-73CV639

Similar Tubes (Not Drop-In Compatible)

Similar transmitting triode with higher Pa_max (20W) and different filament/base; not a drop-in replacement

Same Pa_max (15W) and Va_max (450V) transmitting triode but different filament (6.5V/1.25A) and UX4 base; not pin-compatible

Electrical Specifications

Absolute Maximum

Anode Voltage (max)Plate Voltage (max)450V

Anode Dissipation (max)Plate Dissipation (max)15W

Cathode Current (max)Plate Current (max)40mA

Typical Operating

Anode Voltage (typical)Plate Voltage (typical, Class A)425V

Grid 1 Bias VoltageGrid Voltage (Class A)-40V

Anode CurrentPlate Current (Class A)18mA

Anode ResistancePlate Resistance9,600Ω

TransconductanceTransconductance

Capacitances

Grid-to-Plate CapacitanceGrid-to-Plate Capacitance3.7pF

Grid-to-Cathode CapacitanceGrid-to-Filament Capacitance2.6pF

Anode-to-Cathode CapacitancePlate-to-Filament Capacitance1.4pF

Heater

Heater VoltageFilament Voltage2.5V

Heater CurrentFilament Current2.5A

Notes

DHT tube: the thoriated tungsten filament serves as the cathode; there is no heater-cathode isolation.
Maximum plate current is 40 mA.
The 2.5V filament was chosen for compatibility with standard 2.5V AC filament transformer windings used in contemporary receivers.
Pin 5 is the filament center-tap, used as the cathode return point when operating with AC filament supply.
Designed primarily for RF oscillator and Class A amplifier service at plate voltages up to 450V.
Class A amplifier at Va=425V: Vg=-40V, Ia=18mA, mu=25, gm=2.6 mA/V, ra=9600 Ohm.

Pin Layout — UY5

1Plate

2Grid

3Filament

4Filament

5

References