Pro-Ject Phono Box DS3 B - True Balanced Phono Stage

The Pro-Ject Phono Box DS3 B has a steel chassis which is covered by screwed aluminium panels. This construction brings very good rigidity and splendid isolation against interferences. The Phono Box DS3 B is available in silver or black.

"B" Stands for Balanced

The Phono Box DS3 B employs a true fully balanced gain stage design. Connect your turntable either with the 5-pin mini XLR cable or standard XLR cables & profit of the balanced signal path.

Symmetrical, or also called balanced, transmissions consist of a hot and a cold (also called + and -) signal. Both signal chains effectively carry the same musical information. A true balanced gain stage can now extract the final musical information out of the +/- signals and subtract, remove, all noise that could potentially be added along the transmission.

As there are two separate signal chains, we also needed two individual amplifier sections.

Discrete Circuitry

The Phono Box DS3 B uses fully discrete audio circuitry. A discrete circuit is composed of electronic components which are disparate, individual devices, also called discrete components. Countless hours of listening tests and years of experience have shown us that even the very best Op-Amps do not tend to be so neutral, natural, dynamic or vivid.

Standard phono pre-amplifiers with integrated circuits have a few tens or hundreds of components, but discrete designs will employ hundreds or thousands of components by comparison.

Passive EQ

After treating the balanced symmetrically they are added back together and processed by the fully passive and discrete RIAA equalisation stage. By keeping the gain stage fully symmetrical we can optimise the signal to noise ratios, giving the EQ section the best source to work its magic on.

Fully split passive equalisation allows for better impedance matching and lower deviation from the ideal RIAA curve.

For the balanced XLR outputs, a discrete balancing stage generates a symmetrical signal, so you benefit from balanced signal transmissions again. The single ended RCA outputs run their own fully discrete output stage, served directly by the RIAA EQ.

Cartridge Loading Options

You can connect two turntables at the same time & easily set everything on the front plate. Each input settings are stored in the memory. Large ranges from 40dB up to 65dB are possible.

A fully balanced design makes all the difference here, handling amplification levels this high. You can perfectly match it with a wide variety of cartridges and perfectly integrate it into the rest of your Hifi system, matching the volume levels accurately to other sources like CD players or streaming devices.

Load impedance can be set continuously via potentiometer, a system invented by Pro-Ject Audio Systems. It allows you to seamlessly adjust the impedance during playback and immediately assess the impact of different loading options. This is necessary to find just the right load impedance for your cartridge.

External Power Supply

The Phono Box DS3 B is powered from an external adapter. It is important to keep all the parts which can radiate electromagnetic fields out of the amplifier range. This is the reason why an outboard power supply i.

Due to legal requirements, this power supply must be a switch mode type with guaranteed stand-by mode power consumption 0.1W.

Technical Specifications

• Input impedance: Stepless 10 – 1000 ohms or fix 47k Ohms
• Input Capacitance: 50, 150, 300, 400 pF
• Gain (+ 6dB using XLR Out sockets): 40, 45, 50, 55, 60, 65 dB
• Signal / Noise ratio MM (40dB): 104dBV, 111dBV - "A" weighted
• Signal / Noise ratio MC (60dB): 85dBV, 91dBV - "A" weighted
• THD at 1 kHz: <0.001% MM, < 0,004% MC
• THD (20Hz-20kHz): <0.005% MM, < 0.01% MC
• RIAA-equalization curve accuracy: < 0.25dB / 20Hz - 20kHz
• Subsonic Filter: at 20Hz with 18dB/octave
• Input: 1x 5-pin mini XLR / 1x pair XLR / 1x pair RCA phono
• Line-level Output: 1x pair RCA, 1x pair XLR
• Wiring XLR Sockets: 1 ground, 2 "hot" and 3 "cold"
• Trigger In/Out: 12V on/off detector
• Power supply DC: 18V/500mA
• Power consumption: 18V/max.290mA DC, <0.5 W standby
• Dimensions: 206 x 72 x 194 (205 with sockets) mm
• Weight: 1480g without power supply

Further Information

Pro-Ject Phono Box DS3 B - User Manual

Pro-Ject Phono Box DS3 B - Product Information