FiiO DARKSIDE PRO Low-Noise Regulated Linear Power Supply

As digital audio components become increasingly sophisticated, the quality of their power supply is gaining renewed attention among HiFi enthusiasts. Network streamers, DACs, preamplifiers and headphone amplifiers are particularly sensitive to voltage fluctuations and high-frequency interference originating from conventional switching power supplies. With the DARKSIDE PRO, FiiO Electronics Technology Co. Ltd. addresses this environment with a dedicated linear power supply designed to serve as a stable, low-impedance energy source for demanding audio applications.

Key Facts

• Linear, low-noise power supply developed for audio electronics
• Switchable output voltage of 12 Volt or 15 Volt
• High current capability up to 3 Ampere
• Large toroidal transformer with 75 Watt power reserve
• Extremely low residual ripple of ≤30 µVrms (A-weighted)
• Fine voltage adjustment via precision potentiometer
• Relay-controlled voltage switching for improved efficiency

Concept and Application Area

The DARKSIDE PRO is intended as a universal external power supply for HiFi components that rely on DC input. Typical applications include network players, digital-to-analog converters, compact preamplifiers and desktop headphone amplifiers. Thanks to the selectable output voltage of 12 Volt or 15 Volt, the unit can be adapted to a wide range of devices. The available output current of up to 3 Ampere is designed to ensure sufficient headroom even under dynamic load conditions.

Linear Power Supply Instead of Switching Technology

Unlike widely used switching power supplies, FiiO consistently employs a linear design for the DARKSIDE PRO. At its core is a generously dimensioned toroidal transformer rated at 75 Watt, chosen for its high efficiency and low magnetic stray fields. This type of transformer is widely regarded as particularly suitable for audio applications, as it avoids high-frequency switching noise and provides a solid foundation for subsequent voltage regulation stages. The goal is a calm and stable supply voltage that allows connected audio circuits to operate under optimal conditions.

Regulation and Power Stability

Voltage regulation is handled by a fully discrete circuit using parallel N-MOSFETs. This approach lowers the internal resistance of the power supply and improves its ability to deliver high currents on demand. For digital audio components with rapidly changing load requirements, this can help prevent voltage drops and support stable clocking and signal processing. According to the manufacturer, relay-controlled switching of the transformer taps for 12 Volt and 15 Volt operation further enhances efficiency and reduces heat generation during operation.

Fine Adjustment and Practical Monitoring

For day-to-day use, the FiiO DARKSIDE PRO offers several practical features. A built-in three-LED voltage display provides a quick visual indication of the active output voltage. In addition, a precision potentiometer allows fine adjustment within a narrow tolerance of ±0,2 Volt, enabling users to match the supply voltage precisely to the requirements of the connected device. Integrated protection circuitry, including an overcurrent fuse, completes the safety concept.

Mechanical Design and Connectivity

The power supply is housed in a flat metal enclosure and weighs approximately 2,2 kg, reflecting the substantial transformer and linear architecture inside. DC output is provided via a GX16-2 aviation connector, while the mains input is implemented using a standard three-pin AC socket. A rear-mounted slide switch allows users to select the desired output voltage, helping to prevent incorrect settings when changing devices.

Price and Availability

The FiiO DARKSIDE PRO is initially available exclusively in Asia. According to the manufacturer, broader availability through specialist retailers in Europe is planned for spring 2026. An official retail price for the European market had not yet been announced at the time of publication.

Conclusion

With the DARKSIDE PRO, FiiO Electronics Technology Co. Ltd. positions a specialised solution for users seeking a stable and low-noise power foundation for their audio systems. Its combination of linear architecture, generous current reserves and precise voltage regulation targets a clearly defined niche within the high-quality HiFi segment. Whether and to what extent audible improvements can be achieved will depend on the individual system, but as a technical basis for sensitive audio electronics, the concept is consistently and practically implemented.

Technical Specifications