The 4CX800A is a high-performance ceramic-metal tetrode known for its impressive plate dissipation rating of 800 watts when coupled with forced air cooling. This tube is versatile, excelling in applications such as high-gain grid-driven RF amplifiers and grounded grid service due to its exceptional performance characteristics. The 4CX800A is a reliable and efficient option in electronic amplification, offering a full equivalent to the modern 4CX800A tube.

Named GU74B, this tetrode boasts an oxide cathode with indirect heating, making it suitable for power amplification in broadcasting and SSB equipment. The GU74B tube is designed for optimal performance and has an envelope made of metal-ceramic material. It operates with forced air cooling and has dimensions of 90mm x 71mm, weighing 0.55 kg. The filament voltage required for this tetrode is 12.6 V, drawing a filament current ranging from 3.3 to 3.9 A.

The GU74B tube exhibits a mutual conductance of 26 to 38 mA/V, enabling it to deliver an output power of 0.6 kW. It can handle maximum anode voltages of 2kV, peaking at 4kV, and operates efficiently at frequencies up to 150MHz. With these specifications, the GU74B tetrode is a dependable component for amplification needs in various electronic applications.