The Phono Box DS3 B occupies the mid tier of Pro-Ject's DS3 series of compact hi-fi separates, sitting above the entry-level Phono Box S3 B and below the reference-grade Phono Box RS2. It brings two technologies previously exclusive to Pro-Ject's flagship RS range — a fully balanced signal path and fully discrete circuit topology — to a significantly more accessible price point.
Fully Discrete, Dual-Mono Circuit Topology
Rather than relying on integrated operational amplifiers, the DS3 B constructs its gain stage entirely from individual electronic components. The design is dual-mono throughout: left and right channels each have their own fully independent gain path, sharing no signal-path components. The RIAA equalisation stage is split passive and discrete, achieving an accuracy of less than 0.25 dB across the full 20 Hz–20 kHz bandwidth. The result is a signal-to-noise ratio of 111 dBV (A-weighted) in MM mode and 91 dBV (A-weighted) in MC mode, with total harmonic distortion below 0.001% at 1 kHz for moving magnet cartridges.
True Balanced Connection
Phono cartridges produce a balanced differential signal by nature, and the DS3 B is designed to preserve this from source to output. Three input configurations are offered: a 5-pin mini XLR for turntables fitted with balanced tonearm wiring, a pair of full-size XLR connectors for components with standard balanced outputs, and a conventional RCA pair for single-ended connections. Outputs mirror this flexibility with both XLR and RCA pairs. The balanced XLR outputs deliver a +6 dB gain advantage over the RCA outputs. The chassis combines a steel enclosure with brushed aluminium panels, providing structural rigidity and electromagnetic shielding.
Stepless MC Impedance Loading
A continuously variable impedance dial on the front panel sweeps from 10 to 1,000 ohms, enabling real-time adjustment during playback to find the precise loading for any MC cartridge without interrupting the music. A fixed 47 kΩ setting serves MM cartridges. Input capacitance is selectable at 50, 150, 300, or 400 pF, and gain can be set at 40, 45, 50, 55, 60, or 65 dB. A subsonic filter with a 20 Hz cutoff at 18 dB/octave is also available to suppress low-frequency rumble.
Dual Turntable Support
The DS3 B accommodates two turntables simultaneously — one via the balanced inputs and one via RCA — with each input storing its own impedance, capacitance, and gain settings independently in memory. Switching between sources automatically recalls the correct configuration for each. A 12 V trigger input and output supports integration with automated power-on sequences in multi-component systems.
Construction
The chassis uses a steel inner enclosure wrapped in brushed aluminium panels on all external faces, combining mechanical rigidity with effective electrical shielding. Optional magnetic wooden side panels are available separately for a warmer aesthetic. Designed and handcrafted in Europe.
