Pro-Ject Stereo Box DS3 silver

Pro-Ject Stereo Box DS3: the compact integrated amplifier that lacks nothing

The third generation of the Box Design DS series, the Stereo Box DS3 takes the formula of its predecessor, the DS2, and strengthens it where it matters: more power, an updated Bluetooth module, and a remote control now included. The format remains ultra-compact (206 × 71 × 211 mm, 1.8 kg), but the contents have gained in maturity. Pro-Ject delivers here a stereo integrated amplifier that combines phono preamplification, amplification, and wireless connectivity in an aluminum chassis barely larger than a thick paperback.

An aluminum chassis built to last

The chassis is machined from a block of aluminum, a choice that serves two purposes: protecting the electronics from electromagnetic interference and vibrations, and giving the device a rigidity that plastic or stamped sheet metal cannot offer. The result, in black or anodized silver, remains understated and timeless. For those who prefer a warmer look, Pro-Ject offers wooden side panels (walnut, rosewood, or eucalyptus) that attach with magnets. Installation takes only a few seconds, and the finish matches the brand’s turntables.

At the front, an oversized volume knob relative to the chassis takes center stage. This analog potentiometer is motorized: it follows the commands from the included remote control, which preserves the signal path without going through digital volume control. An input selector, a gain button (+6 dB), a Bluetooth pairing button, and a 6.35 mm headphone jack complete the front panel.

150 watts per channel in dual mono configuration

The amplification section has been revised compared with the DS2. Power rises to 2 × 150 W into 4 ohms (2 × 80 W into 8 ohms), all arranged in a dual mono configuration: each channel has its own amplification stage, which improves stereo separation and reduces crosstalk. Manufacturer measurements indicate separation of -73 dB at 10 kHz and total harmonic distortion below 0.01% at 10 W.

Frequency response is specified at -0.1 dB / +0.3 dB across the 20 Hz – 20 kHz band, and the signal-to-noise ratio reaches 98 dB (105 dB A-weighted). These figures are remarkable for a device of this size. In practice, the DS3 can drive low-sensitivity floorstanding speakers without any sign of running out of steam, something its size does not suggest.

An integrated phono preamp, compatible with MM and MC

Where many compact integrated amplifiers make do with a line input, the Stereo Box DS3 includes a phono stage compatible with moving magnet (MM) and moving coil (MC) cartridges. Gain is set at 40 dB for MM cartridges (47 kΩ input impedance) and 60 dB for MC cartridges (100 Ω input impedance). An MM/MC switch is accessible at the rear of the chassis.

This integration avoids the purchase of a separate phono preamplifier, a significant expense when building a system around a turntable. The quality of the phono stage remains tied to the space and budget available in a device of this format: owners of high-end, very low-output MC cartridges may prefer a dedicated preamp, but for the vast majority of common MM and MC cartridges, the result is entirely usable.

Five sources, one single box

The rear panel brings together five inputs in total. The phono input (pair of RCA + ground terminal) sits alongside three RCA line inputs, plus a Bluetooth 5.0 receiver with support for aptX and aptX HD codecs (A2DP profile). The Bluetooth stream can reach 24 bits / 48 kHz, placing wireless streaming quality a notch above standard SBC.

On the output side, the speaker terminals accept 4 mm banana plugs, spades, or bare wire. Two pairs of RCA outputs complete the setup: one variable output (whose level follows the volume potentiometer) for connecting a subwoofer or a secondary power amplifier, and one fixed output (constant level, independent of volume) for feeding a recorder or distributing the signal to another room. The RCA connectors are gold-plated.

The 12 V trigger inputs and outputs allow other Pro-Ject devices (or compatible ones) to be turned on or off at the same time as the DS3, a practical detail in a multi-component system.

A headphone output that is far from an afterthought

The front headphone jack (6.35 mm jack) delivers 2 × 450 mW into 32 ohms. That is high power for an integrated amplifier of this size, enough to drive most low-sensitivity hi-fi headphones. Pro-Ject has equipped this output with its own amplification stage, separate from the main circuit: the headphones are not simply connected in parallel to the speaker output via a resistor, which results in better control and less background noise.

What has changed compared with the DS2

The Stereo Box DS3 looks very much like its predecessor, and that is deliberate: Pro-Ject has kept the chassis dimensions to ensure compatibility with the wooden side panels from the DS2 series. The changes are under the hood and in the box.

Output power has been significantly increased (150 W versus about 55 W into 4 ohms for the DS2, according to the manufacturer’s data at the time). The Bluetooth module moves to version 5.0 with support for aptX HD, absent from the previous model. And the remote control, which was an optional accessory on the DS2, is now included as standard. The external power supply remains the same format (36 V / 5.5 A), compatible with 100 – 240 V mains.

Technical specifications

Audio performance

• Output power
  • 2 x 80 W into 8 ohms
  • 2 x 150 W into 4 ohms
• Frequency response: 20 Hz – 20 kHz (-0.1 dB / +0.3 dB)
• Signal-to-noise ratio: 98 dB (105 dB A-weighted)
• Total harmonic distortion (THD): < 0.01% at 10 W
• Channel separation: -73 dB at 10 kHz
• Dual mono design for better channel separation

Phono section

• Compatibility: MM and MC cartridges
• Gain
  • MM: 40 dB
  • MC: 60 dB
• Impedance
  • MM: 47 kΩ
  • MC: 100 Ω

Bluetooth connectivity

• Version: Bluetooth 5.0
• Codecs: aptX, aptX HD
• Profile: A2DP
• High-quality streaming up to 24 bits / 48 kHz

Inputs

• 1 phono input (MM / MC)
• 3 RCA line inputs
• Bluetooth 5.0 (aptX, aptX HD, A2DP)

Outputs

• Speaker terminals compatible with banana plugs, spades, or bare wire
• 1 variable RCA output (subwoofer / secondary amplifier)
• 1 fixed RCA output (recording / distribution)
• High-power headphone output: 2 x 450 mW
• Trigger In / Out

Power supply and consumption

• Power supply: 36 V / 5.5 A
• Mains compatibility: 100 – 240 V
• Standby power consumption: < 0.5 W

Dimensions and weight

• Dimensions (W x H x D): 206 x 71 x 211 mm (223 mm with connectors)
• Weight: 1.8 kg (excluding power supply)

Design and construction

• Machined aluminum anti-vibration and anti-interference chassis
• Available finishes: black, silver
• Designed and manufactured in Europe

Included accessories

• Remote control with motorized volume control

Recommended uses

• Complete Hi-Fi systems combining vinyl and digital
• Demanding floorstanding or bookshelf speakers
• High-quality Bluetooth streaming
• Audiophile headphone listening