The Fosi Audio PSU20 3-Channel 40W Linear Power Supply delivers clean, stable electricity to up to three compatible Hi-Fi components with fully isolated power channels and ultra-low ripple noise as low as 0.1mV. Featuring an 80W pure-copper toroidal transformer, two selectable DC outputs supporting 5V, 12V, and 15V, and a dedicated 5V USB-A output, the PSU20 provides flexible power distribution for DACs, headphone amplifiers, CD transports, and preamplifiers. Premium Nippon Chemi-Con capacitors, independent voltage regulation, automatic cooling, and built-in electrical protection make the PSU20 a reliable solution for reducing power adapter clutter and supporting sensitive audio equipment.
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Fosi Audio PSU20 3-Channel 40W Linear Power Supply

Upgrade your Hi-Fi system with the Fosi Audio PSU20 3-Channel 40W Linear Power Supply, a premium power solution designed to deliver clean, stable, and reliable electricity to your favorite audio components. Featuring a custom 80W pure-copper toroidal transformer, three fully isolated power output channels, and ultra-low ripple noise as low as 0.1mV, the PSU20 provides a refined alternative to conventional switching power adapters. With two selectable DC outputs and one USB-A power output, the PSU20 can power up to three compatible devices simultaneously, making it an excellent addition to systems built around DACs, headphone amplifiers, CD transports, and stereo preamplifiers.

Designed to minimize electrical interference and preserve audio system performance, the PSU20 uses a carefully engineered linear power architecture with independent rectification, filtering, voltage regulation, and protection circuits for each output channel. Unlike conventional switching power supplies, which rely on high-frequency switching circuits, the PSU20 uses linear regulation to provide a stable DC output with a controlled noise profile. Premium Nippon Chemi-Con capacitors help reduce unwanted voltage fluctuations and electrical ripple, while a high-performance rectifier and dedicated voltage regulators support clean, consistent power delivery. This approach can help reduce power-related interference in compatible audio equipment, particularly sensitive low-noise components.

Flexibility is one of the PSU20's greatest advantages. Its first DC output provides selectable 12V or 15V power with a maximum rated output of 20 watts, while the second DC output offers selectable 5V or 12V power with a maximum rating of 15 watts. A dedicated USB-A connection supplies 5V/1A power for compatible USB-powered devices. Together, these three independently isolated outputs deliver a combined rated capacity of 40 watts, allowing listeners to replace multiple individual power adapters with one centralized power solution. The included DC-to-DC power cables help reduce cable clutter while creating a cleaner, more organized audio system.

Inside the PSU20 is a custom pure-copper toroidal transformer rated at 80 watts with a peak capability of up to 100 watts, providing the foundation for stable power conversion and regulation. Its GBU806 rectifier bridge is rated for 600V and 8A, while three LM1085IT regulators and one ST78M05 regulator provide carefully controlled voltage delivery. Each output channel operates through dedicated regulation and protection circuitry to help prevent electrical interaction between connected components. With ripple levels as low as 0.1mV, the PSU20 is engineered to support sensitive audio electronics that benefit from consistent, low-noise power.

For reliable long-term operation, the PSU20 incorporates automatic thermal management and multiple electrical protection systems. A custom low-noise cooling fan activates when the internal temperature reaches approximately 55°C (131°F), operating at a rated noise level of just 30dB. Built-in over-temperature, overvoltage, and overcurrent protection help safeguard the power supply and compatible connected equipment. Its durable desktop enclosure and unified component styling allow it to integrate naturally into modern Hi-Fi systems. Whether you're powering a dedicated headphone listening station, a desktop DAC and preamplifier combination, or multiple compatible low-voltage audio components, the Fosi Audio PSU20 delivers a convenient, organized, and performance-focused power solution.

Specifications

• Brand: Fosi Audio
• Model: PSU20
• Product Type: 3-channel linear DC power supply
• Power Supply Design: Linear regulated power supply
• Power Output Channels: 3 fully isolated channels
• Maximum Connected Devices: 3 compatible devices simultaneously
• Total Rated Output Power: 40 watts
• Transformer: Custom pure-copper toroidal transformer
• Transformer Rating: 80 watts
• Transformer Peak Power: Up to 100 watts
• AC Power Input: 1 × AC mains power connection
• AC Voltage Selection: Manual 115V/230V selection
• 115V Setting: Supports 100–120V AC, 60Hz
• 230V Setting: Supports 220–240V AC, 50Hz
• DC Power Outputs: 2 DC barrel-style power connections
• USB Power Output: 1 USB-A connection
• DC Output 1 Voltage: Selectable 12V or 15V DC
• DC Output 1 Rated Power: 20 watts
• DC Output 2 Voltage: Selectable 5V or 12V DC
• DC Output 2 Rated Power: 15 watts
• USB-A Output Voltage: 5V DC
• USB-A Output Current: 1A
• USB-A Output Rated Power: 5 watts
• Supported Output Voltages: 5V, 12V, and 15V DC
• Output Isolation: Independent rectification, filtering, regulation, and protection for each channel
• Voltage Regulation: Four linear regulator components
• Linear Regulators: 3 × LM1085IT and 1 × ST78M05
• Rectifier Bridge: GBU806
• Rectifier Voltage Rating: 600V
• Rectifier Current Rating: 8A
• Capacitors: Premium Nippon Chemi-Con capacitors
• Output Ripple: As low as 0.1mV
• Cooling System: Automatic temperature-controlled cooling fan
• Cooling Fan Activation Temperature: 55°C (131°F)
• Cooling Fan Noise Level: Approximately 30dB
• Over-Temperature Protection: Yes
• Overvoltage Protection: Yes
• Overcurrent Protection: Yes
• Operating Temperature Range: -20°C to 40°C (-4°F to 104°F)
• Full-Load Temperature Rise: Approximately 25°C (77°F)
• Compatible Equipment: Devices requiring supported DC voltages, power levels, polarity, and connectors
• Recommended Applications: Compatible DACs, CD transports, headphone amplifiers, preamplifiers, and low-voltage audio accessories
• Power Distribution: Three independent output channels with a combined 40W rating
• Power Cable Length 1: 1.2 meters (47.2 inches)
• Power Cable Length 2: 0.3 meters (11.8 inches)
• Color: Black
• Certifications: CE, FCC, and RoHS
• EAN: 6976136961482
• Analog Audio Inputs: None
• Digital Audio Inputs: None
• Audio Outputs: None; all three outputs provide electrical power only
• 12V Trigger: No dedicated 12V trigger connection
• Built-In Audio Amplifier: No
• Bluetooth Connectivity: No
• Wi-Fi Connectivity: No
• Manufacturer Warranty: 24-month limited warranty
• Included Accessories: Fosi Audio PSU20 Linear Power Supply, 1.2m DC-to-DC power cable, 0.3m DC-to-DC power cable, AC power cord, and user manual

What It's Great At

• Clean, Low-Noise Power Delivery: Linear regulation, premium capacitors, and ripple noise as low as 0.1mV help reduce unwanted power-supply interference in compatible Hi-Fi equipment.
• Powering Three Components Simultaneously: Two DC outputs and one USB-A connection provide a combined 40 watts of rated power for compatible DACs, headphone amplifiers, CD transports, preamplifiers, and audio accessories.
• Fully Isolated Power Channels: Independent rectification, filtering, regulation, and protection circuitry for each output helps minimize electrical interaction between connected components.
• Flexible Voltage Selection: Selectable 5V, 12V, and 15V DC output options accommodate a wide range of supported low-voltage audio devices.
• Premium Power Supply Components: An 80W pure-copper toroidal transformer, Nippon Chemi-Con capacitors, a GBU806 rectifier, and dedicated linear regulators provide a robust foundation for consistent power delivery.
• Reliable, Quiet Operation: An automatic 30dB cooling fan and built-in over-temperature, overvoltage, and overcurrent protection support stable operation during extended listening sessions.

FAQ Section

Q: What is the Fosi Audio PSU20 used for?
A: The Fosi Audio PSU20 is a 3-channel linear power supply designed to deliver clean, stable DC power to compatible audio components. It can replace multiple individual power adapters while supplying electricity to devices such as DACs, headphone amplifiers, CD transports, and stereo preamplifiers. It is not an audio amplifier or signal-processing device.

Q: How many devices can the Fosi Audio PSU20 power simultaneously?
A: The PSU20 can power up to three compatible devices at the same time. It features two DC barrel outputs and one USB-A power output, providing a combined rated output of 40 watts. The connected devices must remain within the voltage and power limits of their respective outputs.

Q: What power outputs does the Fosi Audio PSU20 have?
A: The PSU20 provides three isolated outputs. DC Output 1 offers selectable 12V or 15V power with a maximum rating of 20 watts, DC Output 2 offers selectable 5V or 12V power rated at 15 watts, and the USB-A output provides 5V/1A power rated at 5 watts. All three outputs are dedicated to supplying electrical power rather than carrying audio signals.

Q: What is the benefit of a linear power supply for Hi-Fi audio?
A: A linear power supply uses transformer-based power conversion and linear voltage regulation to provide stable DC power with a controlled noise profile. The PSU20 offers ripple levels as low as 0.1mV, which may help reduce power-related interference in sensitive audio equipment. The degree of audible improvement depends on the connected components and their internal power regulation.

Q: Can I use the Fosi Audio PSU20 with any DAC or headphone amplifier?
A: The PSU20 works with compatible audio equipment that meets its voltage, current, power, connector, and polarity requirements. Before connecting a device, verify that it operates at the selected output voltage and that its power consumption does not exceed the rating of the chosen PSU20 output. Devices requiring higher power levels or different electrical specifications should not be connected.

Q: Does the Fosi Audio PSU20 have a cooling fan?
A: Yes. The PSU20 includes a temperature-controlled cooling fan that automatically activates when its internal temperature reaches approximately 55°C (131°F). The fan operates at a rated noise level of approximately 30dB and helps maintain stable performance during extended use.

Q: Does the Fosi Audio PSU20 include electrical protection features?
A: Yes. The PSU20 includes over-temperature, overvoltage, and overcurrent protection to help safeguard the power supply and connected audio equipment. Each of its three output channels incorporates dedicated regulation and protection circuitry for stable, isolated power delivery.

Q: Does the Fosi Audio PSU20 have audio inputs, outputs, or a 12V trigger?
A: No. The PSU20 is a dedicated electrical power supply and does not include analog or digital audio connections or a dedicated 12V trigger. It features one AC mains input and three DC power outputs: two barrel-style DC outputs and one USB-A power output. Its 12V settings supply continuous DC power rather than trigger-control signals.