GU74B/4CX800A Ceramic Power Tetrode

GU74B/4CX800A tube specs The table below is a quick-reference snapshot for the GU74B/4CX800A tube specs that buyers commonly check before ordering. Because this is a tetrode vacuum tube, most real-world compatibility questions come down to socket/base fit, airflow/ducting, and whether your operating conditions line up with the datasheet ratings. 4CX800A / GU-74B general specifications Specification Details Tube type Ceramic/metal power tetrode (4CX800A / GU-74B family) Plate (anode) dissipation (max) 800 W Screen dissipation (max) 15 W Control grid dissipation (max) 2 W Amplification factor (grid-to-screen) 6.5 (nominal) Frequency for maximum ratings 150 MHz Cathode/filament Oxide-coated Filament voltage 12.6 V Filament current (at 12.6 V) 3.6 A Interelectrode capacitance (grounded cathode): input 51 ± 5 pF Interelectrode capacitance (grounded cathode): output 11 ± 2 pF Interelectrode capacitance (grounded cathode): feedback 0.09 pF Cooling method Forced air Base type 7-pin special Recommended socket (datasheet reference) SK-1A Maximum DC plate voltage (rating reference) 2,500 V Maximum DC plate current (rating reference) 0.8 A Mounting / operating position Any orientation 4CX800A/GU74B tube datasheet download Before you finalize an order, use the 4CX800A datasheet to confirm ratings, airflow requirements, and mechanical details for your installation. This reference is the best place to validate operating limits, socket guidance, and cooling expectations against the tube marking you are replacing. GU74B/4CX800A tube substitute & equivalent information GU-74B / 4CX800A is typically selected when the surrounding hardware is already designed around the same base format and forced-air cooling approach. Treat “equivalent” as a two-step check: confirm the mechanical interface first (socket/base, contact surfaces, clearances, airflow path), then confirm the electrical operating envelope (drive method, duty cycle, and how conservatively the tube is run in practice). In the right hardware, this can be used as a direct replacement for 4CX800A Eimac tubes where fit and operating conditions match, and it is also commonly referenced as a Svetlana 4CX800A/GU74B tube equivalent in RF amplification service. If you are replacing a legacy, brand-marked tube, verify the whole installation context rather than relying on the model number alone. For buyers working on an RF deck or GU74B amplifier, the practical “do I have the right tube?” checks are still the same: confirm socket/base compatibility and clearances, confirm the forced-air path and airflow expectations, then validate your typical operating approach (drive and duty cycle) against the datasheet ratings. As established vacuum tube manufacturers, we can help you confirm compatibility if you share your current tube marking plus the amplifier/generator model and your cooling setup. If your project is more audio-focused than transmit/RF service, you may also want to browse audio tubes for sale for other amplification designs and tube families.