Shuguang 274B Rectifier Tube 1 Piece Full-Wave High Vacuum 5V for 300B 2A3 Tube Amplifier HIFI Audio DIY

Shuguang 274B Rectifier Tube 1 Piece Full-Wave High Vacuum 5V for 300B 2A3 Tube Amplifier HIFI Audio DIY Model No: SG-274B The Shuguang 274B is a high-performance, directly heated full-wave rectifier tube designed for high-voltage power supplies in tube amplifiers and other vacuum-tube audio equipment. Manufactured by Shuguang, it combines high-vacuum construction, carefully processed electrodes, and robust internal structure for stable and reliable rectification. A special cathode treatment is used to provide a smooth, durable emitting surface with strong electron emission. During production, the tube undergoes an extended evacuation process using high-vacuum equipment to achieve a high degree of internal vacuum. The tube is also subjected to high-voltage conditioning, helping improve stability and reliability when operating under elevated B+ voltages. Features High-vacuum construction for stable high-voltage operation Special electrode processing for strong and consistent electron emission High-voltage conditioning improves long-term stability Peak inverse voltage: over 850V DC output current: over 150mA Full-wave rectification for vacuum-tube amplifier power supplies Designed to minimize arcing under normal high-voltage operating conditions Suitable for many 274B / 5U4G-type rectifier applications Ideal for 300B, 2A3, 45 and other tube amplifier power supplies, subject to circuit requirements Typical Specifications Parameter Specification Tube Type 274B Function Full-Wave Rectifier Construction Directly Heated Heater Voltage 5V Heater Current Approx. 2A* Peak Inverse Voltage ≥ 850V DC Output Current ≥ 150mA Base Octal Manufacturer Shuguang Application Tube Amplifier High-Voltage Power Supply *The image supplied does not state the heater current; 5V/2A is the conventional 274B specification and should be confirmed against the manufacturer's datasheet for this exact production version. 274B and 5U4G Compatibility The Shuguang 274B is commonly used in applications where a 5U4G-style octal rectifier is specified. However, rectifier tubes should not be treated as universally interchangeable simply because their bases and pin connections are similar. Before replacing a 5U4G, 5AR4/GZ34, 5R4 or another rectifier with the 274B, verify the amplifier's heater supply, transformer voltage, DC current requirement, first filter capacitor value and resulting B+ voltage. Ideal for Tube Amplifier Power Supplies With its classic directly heated rectifier architecture and high-voltage capability, the Shuguang 274B is particularly well suited to traditional tube amplifier power supplies. It can be used in DIY and replacement applications for 300B SET amplifiers, 2A3 amplifiers, tube preamplifiers and other high-voltage vacuum-tube circuits where the electrical requirements are compatible. For builders seeking a traditional full-wave vacuum rectifier with strong high-voltage capability and the characteristic behavior of a directly heated rectifier, the Shuguang 274B is a practical choice for both new builds and restoration projects.