Pro-Ject Power Box DS3 sources black

Pro-Ject Power Box DS3 Sources: a linear power supply for six devices

Behind every hi-fi source, there is a power supply. The one supplied as standard does the job, but a dedicated linear power supply does better: it isolates the audio circuits from the mains and delivers cleaner current, with measurable effects on background noise. The Power Box DS3 Sources takes this principle and applies it to an entire Pro-Ject Box Design system, grouping up to six outputs in a single compact unit.

Why replace the original power adapters

Devices in the Box Design range come with switching power adapters. These compact power supplies do their job, but they generate high-frequency noise that ends up in the audio signal. A linear power supply works differently: its toroidal transformer provides galvanic isolation between the mains and the device, blocking mains interference before it reaches the audio circuit.

The Power Box DS3 Sources takes this logic further with copper foil shielding between the transformer’s primary and secondary windings. This additional shielding reduces capacitive coupling between the two windings, a source of noise that galvanic isolation alone does not fully address.

Six outputs, three voltages, one single unit

The device offers six outputs spread across three voltages. Two 9 V / 2 A max outputs (1.3 mm connector) power compact sources such as the CD Box, Stream Box, DAC Box S, or Bluetooth Box. Three 18 V / 1 A max outputs (2.5 mm connector) support more power-hungry devices: phono preamps (Phono Box DS2), headphone amplifiers (Head Box DS), converters (Pre Box DS2 Digital), as well as the Tube Box and Stream Box S2 Ultra. One final 15 V DC output (2.1 mm connector) is reserved for Pro-Ject turntables with DC power supply.

Six connection cables are included, one per output. Pro-Ject also offers its optional Connect it Power cables, featuring enhanced shielding, in lengths of 0.82 m, 1.23 m, and 1.85 m.

The practical benefit is twofold. On the one hand, a single unit replaces up to six mains adapters, freeing up space on the power strip and simplifying cabling. On the other hand, all sources share a power supply of identical quality, which helps standardize the performance of the entire system.

Current filtering and regulation

The filtering capacity reaches 10,000 µF, a high value for a device of this size. The low-ESR (equivalent series resistance) capacitors reduce losses and improve response to transient current demands. Residual output ripple remains below 1 mV, resulting in a very low noise floor.

The regulation circuit maintains stable voltage regardless of the load. A soft-start system limits current spikes at power-on, protecting connected components and preventing sudden stress on the transformer. Overvoltage protection completes the setup.

Trigger output and daisy-chaining

A 12 V trigger output (2.5 mm jack) lets you switch a compatible Pro-Ject device on or off from the Power Box DS3 Sources’ power switch. This function simplifies management of a multi-component system: a single button on the front panel controls the power supply and can trigger the startup of another device in sequence.

Compatibility and limitations to be aware of

The list of compatible devices covers most of the Box Design range, from CD players to converters, including phono preamps, streamers, and headphone amplifiers. The 15 V output is suitable for most Pro-Ject turntables with a DC motor.

Two restrictions deserve attention. Turntables with a heavy platter and high power consumption, such as the X8, Xtension 9/10/12, RPM 9/10, and models in the Signature line, require a more powerful power supply: in this case, Pro-Ject recommends the Power Box RS2 Phono or the Power Box RS Uni TT. Integrated and power amplifiers are not supported either.

Technical Specifications

Power and Outputs

• Linear, non-switching power supply to eliminate interference
• Capacity: up to 6 devices simultaneously
• Available outputs:
  • 2 × 9 V / 2 A max (1.3 mm connector)
  • 3 × 18 V / 1 A max (2.5 mm connector)
  • 1 × 15 V DC for Pro-Ject turntable (2.1 mm connector)
• High-capacitance filtering: 10,000 µF
• Ripple: < 1 mV for an ultra-stable, low-noise supply
• Soft-start system with no inrush current

Compatibility

• 9 V products: CD Box, Stream Box, DAC Box, Bluetooth Box
• 18 V products: Phono Box, DAC Box DS, Head Box, Pre Box DS2 Digital, Stream Box S2 Ultra, Tube Box
• Pro-Ject 15 V DC turntables: majority of standard DC models
• Not compatible with high-consumption high-end turntables:
  • Pro-Ject X8, Xtension 9 / 10 / 12, RPM 9 / 10, Signature Line
  • For these models: use Power Box RS2 Phono or Power Box RS Uni TT

Build and Finish

• Rigid aluminum chassis for shielding against electromagnetic interference
• Audio-grade toroidal transformer with copper shielding for maximum isolation
• Overvoltage protection and low-noise components
• Available finishes: black or silver
• Optional magnetic wooden side panels
• Made in Europe

Full Technical Specifications

• Mains input: 115 V / 230 V AC
• DC outputs: 2 × 9 V / 2 A, 3 × 18 V / 1 A, 1 × 15 V for turntable
• Filtering capacity: 10,000 µF
• Output ripple: < 1 mV
• Trigger output: 2.5 mm jack
• Dimensions (W × H × D): 206 × 71 × 209 mm (including connectors)
• Weight: 3.0 kg

Key Benefits

• Single power supply for up to 6 Pro-Ject devices
• High-end linear power supply with extremely low noise
• High filtering capacity and audiophile-grade components for improved sound quality
• Robust solid aluminum design
• Cost-effective and convenient alternative to multiple separate power supplies