Pro-Ject Power Box RS2 SOURCES silver

After the Power Box RS2 Phono, dedicated to the turntable + phono preamplifier pairing, Pro-Ject extends its external linear power supply approach to sources and preamplifiers in the RS/RS2 range. The Power Box RS2 SOURCES brings together four independent linear power supplies in a single aluminum enclosure, all delivering 20 V DC. One unit, one mains cable, up to four devices powered.

Why use an external linear power supply

Devices in the Box Design RS and RS2 series (the CD Box RS2 T, the DAC Box RS2, the Pre Box RS2 Digital, and the Phono Box RS2) are supplied with a switching power adapter. This type of power supply, compact and inexpensive, generates high-frequency electrical noise that can travel back into the signal chain. The issue is even more noticeable with low-level sources, where the signal-to-noise ratio determines the finesse of reproduction.

A linear power supply works differently. It converts AC mains current through a transformer, then rectifies and filters the resulting voltage, without using the rapid switching that characterizes switching power supplies. The result: a more stable output voltage, with fewer disturbances injected into the powered device.

What the enclosure contains

The toroidal transformer at the center of the chassis is the main component. Pro-Ject has added copper foil shielding to the main transformer, which acts as an isolation transformer between the mains and the powered circuits. This shielding limits capacitive coupling between the primary and secondary windings, reducing the transfer of mains interference to the outputs.

Downstream from the transformer, the voltage is rectified with precise regulation of the secondary voltage. Filtering capacity reaches 10,000 μF, distributed across low-ESR (equivalent series resistance) capacitors. Residual output ripple remains below 6 mV peak-to-peak, a low value that limits the background noise perceptible in connected devices.

Each of the four outputs delivers 20 V with a tolerance of ±0.5%, at a maximum current of 2 A. The available power reserve far exceeds what a standard power adapter provides, which benefits the circuits during transient current demands (musical attacks, track changes on a CD player).

Protections and startup

A soft-start system limits inrush current at power-on. Without this precaution, the initial current peak caused by charging the capacitors could trip a protection circuit or place unnecessary stress on the components. The Power Box RS2 SOURCES also includes overvoltage protection. A rocker switch on the rear panel allows the mains power to be completely disconnected.

Connectivity and supplied cables

The four outputs use mini XLR connectors, identical to those on the 20 V power inputs of RS/RS2 devices. Four mini XLR to mini XLR cables are included in the box, ready to use. Pro-Ject’s Connect it Power mains cable (1 m) is also included. The mains input accepts 115 V or 230 V AC thanks to a voltage selector located on the rear panel, making the device usable in most regions of the world.

Using mini XLR rather than standard coaxial DC plugs provides mechanical locking and better long-term contact stability. It is a consistent choice for devices in this price range.

Which devices can be connected

The Power Box RS2 SOURCES supports all Pro-Ject devices in the RS and RS2 series operating on 20 V. In practice, this covers digital sources and preamplifiers: the CD transport CD Box RS2 T, the DAC Box RS2 converter, the Pre Box RS2 Digital preamplifier/DAC, and the Pre Box RS. Devices operating at other voltages (15 V for turntables, 18 V for phono preamplifiers) are not compatible: these fall under the Power Box RS2 Phono.

It is not necessary to connect four devices to use the Power Box RS2 SOURCES. One or two devices can be powered on their own, with the unused outputs simply remaining inactive.

Construction and finishes

The chassis is made of rigid aluminum, a material that helps shield against external electromagnetic interference. Two finishes are available: black or silver, visually matching the other devices in the RS2 series. The dimensions (206 × 71 × 209 mm) and format match those of Box Design RS2 devices, making stacking or side-by-side placement on a hi-fi cabinet easier. The weight of 3.55 kg, high for an enclosure of this size, reflects the presence of the massive toroidal transformer inside. Manufacturing is European.

Technical specifications

General overview

• Type: universal linear power supply
• Compatibility: Pro-Ject RS / RS2 devices at 20 V
• Number of devices powered simultaneously: up to 4
• Manufacturing: Europe
• Available finishes: black, silver

Design and architecture

• Non-switching (linear) power supply
• High-quality toroidal audio transformer
  • Copper shielding on the main transformer
• Rigid interference-resistant aluminum chassis

Electrical performance

• Input voltage: AC 230 V / 50 Hz (IEC C15)
• Output voltage: 4 × 20 V ±0.5%
• Output current: 2 A
• Residual ripple: max. 6 mV pp
• Filtering capacity: 10000 μF
• Low-ESR capacitors
• Regulation by precise rectification of the secondary voltage

Protection

• Soft Start inrush current protection system
• Overvoltage protection

Sonic and functional advantages

• Powers up to 4 RS / RS2 electronic components with a single power supply
• Reduction of electrical interference and background noise
• Improved soundstage and detail resolution
• Higher power reserve than a standard power supply

Connectivity and included accessories

• 4 mini XLR to mini XLR cables
• Pro-Ject Connect it Power mains cables included (1 m)

Dimensions and weight

• Dimensions (W × H × D): 206 × 71 × 209 mm
• Weight: 3.55 kg