TUBEOFILE
1625 — Beam Tetrode, UX7 | Tubeofile | Tubeofile
← Browse Medium quality — at least 60% of universal parameters and pins are present, but some key data is missing. Verify specific values against datasheets before critical use.
Known Equivalents & Substitutes
CV659 VT136
Similar Tubes (Not Drop-In Compatible)
Same electrical characteristics but 6.3V/0.9A heater on UX5 base — different base and heater voltage, not pin-compatible Electrical Specifications
Absolute Maximum
Anode Voltage (max) Plate Voltage (max) 750V
Screen Voltage (max) Screen Voltage (max) 350V
Anode Dissipation (max) Plate Dissipation (max) 30W
Screen Dissipation (max) Screen Dissipation (max) 3.5W
Max Grid Resistor
Notes
The 1625 is the 12.6V heater military version of the 807. Electrically identical except for heater voltage and base type. Uses a 7-pin UX7 base with a top-cap plate connection. The 807 uses a 5-pin UX5 base — the two are NOT interchangeable without an adapter. TDSL and ARRL references list RF Class C, Class B, and AB1 operating conditions. Primary use was in military AN/ARC-5 command set transmitters. Widely available as war surplus; commonly adapted for amateur radio transmitter use at 12.6V mobile supply. Datasheet capacitances measured with external shield: Cgk=11pF, Cak=7pF, Cgp=0.2pF. Pin Layout — UX7
1 2 3 4 5 6 7
1 Control Grid (g1)
2 No Connection
3 Heater
4
Grid Resistor (max, RF Class C)
0.01MΩ
Typical Operating
Anode Voltage (typical) Plate Voltage (typical, RF Class C) 600V
Screen Voltage (typical) Screen Voltage (typical, RF Class C) 200V
Grid 1 Bias Voltage Grid Voltage (typical, RF Class C AM) -90V
Anode Current Plate Current (typical, RF Class C) 100mA
Screen Current Screen Current (typical, RF Class C) 10mA
Output
Output Power Power Output (RF Class C, CW) 50W
Capacitances
Grid-to-Plate Capacitance Grid to Plate Capacitance (max) 0.2pF
Grid-to-Cathode Capacitance Control Grid to Cathode Capacitance 11pF
Anode-to-Cathode Capacitance Plate to Cathode Capacitance 7pF
Heater
Heater Voltage Heater Voltage 12.6V
Heater Current Heater Current 0.45A
Heater
TC Top Cap — Plate (top cap)