About the Pro-Ject Phono Box DS3 B

An extremely versatile phono preamp

Precise cartridge-loading adjustments can be made from the front panel of the Pro-Ject DS3 B.
An extremely versatile phono preamp
If you want the flexibility to use a wide range of phono cartridges, the Pro-Ject Phono Box DS3 B has you covered. It features adjustable input capacitance settings for moving magnet and high-output moving coil cartridges, plus gain-setting options to better match your cartridge to your system. The knob on the front offers continuously variable impedance from 10-1000 ohms, so you can really dial in a low-output moving coil cartridge. A switchable subsonic filter protects your amplifier and speakers from power-wasting low-frequency rumble below 20 Hz.
Excellent build quality
Pro-Ject paid a great deal of attention to detail when designing and building the DS3 B — inside and out. There's discrete audio circuitry in a full dual mono configuration inside for optimal channel separation and clarity. The back panel features standard RCA and balanced XLR inputs and outputs, plus a five-pin mini XLR "balanced stereo" input. When you're using compatible turntables with balanced output , the preamp's true balanced gain stage helps reduce channel noise and enhance detail. A steel and aluminum chassis minimizes vibration and electromagnetic interference that can mar your listening experience.
Product highlights:
- compatible with moving magnet and moving coil phono cartridges
- discrete audio circuitry in a full dual mono configuration for optimal channel separation and clarity
- true balanced gain stage for reduced channel noise and enhanced detail
- front-panel input impedance control for low output moving coil cartridges
- subsonic filter reduces low-frequency rumble and wasted amplifier power (-18dB/octave at 20 Hz)
- steel and aluminum chassis shields from vibration and electromagnetic interference
Performance specs:
- switchable loading: continuously variable from 10-1000 ohms or fixed 47k
- capacitance settings: 50pF, 150pF, 300pF, or 400pF (for MM and high-output MC cartridges)
- gain settings: 40dB, 45dB, 50dB, 60dB, and 65dB
- RIAA response accuracy: 0.25dB (20-20,000 Hz)
- THD (20-20,000Hz): 0.005% (MM); 0.01% (MC)
- signal-to-noise ratio: 104 dBV (MM); 85 dBV (MC)
Connections:
- balanced XLR inputs and outputs
- unbalanced stereo RCA input and output
- 5-pin mini XLR balanced stereo input
- 12-volt trigger input and output
Dimensions and warranty:
- 8-1/8"W x 2-13/16"H x 9-7/16"D
- weight: 3.6 lbs.
- warranty: 2 years
- Our 60-day money-back guarantee
- MFR # 9120097829375
What's in the box:
Pro-Ject Phono Box DS3 B owner's manual
- Phono (MM/MC) pre-amplifier
- AC power adapter (with attached 4' DC cord)
- 3 AC power plug iinserts (US/EU/UK)
- Instructions For Use
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More details on the Pro-Ject Phono Box DS3 B

Features & specs
Features | ||
---|---|---|
Cartridge Type | MM, MC | |
Subsonic Filter | Yes | |
Cartridge Loading | Variable | |
Adjustable Resistance Load | Yes | |
Adjustable Capacitance Load | Yes | |
Vacuum Tube | No | |
Connections | ||
RCA Inputs | 1 Pair | |
XLR Inputs | 5-pin mini-XLR | |
RCA Output | 1 Pair | |
XLR Output | Yes | |
USB Output | No | |
3.5mm Output | No | |
Optical Output | No | |
Coaxial Output | No | |
Specs | ||
Signal-to-noise Ratio (MM) | 104 | |
Signal-to-noise Ratio (MC) | 85 |
Product Research
Features
True Balanced Design: The Pro-Ject Phono Box DS3 B incorporates a true, fully balanced gain stage design that can extract the final musical information out of the audio signals, plus subtract and remove all noise that could potentially be added along the transmission. It features a fully discrete & symmetrical gain stage with balanced input and outputs for dynamic and detailed sound from your vinyl record collection.
- Fully Discrete Gain Stage: The gain stage of the new Phono Box DS3 B uses a fully discrete circuit layout composed of separate, individual electronic components and devices. The amplifier section is built out of single components and doesn't use any integrated circuits for better results when it comes to sound quality.
- Semi-Passive EQ: After treating the balanced audio signals independently, they are added back together and are processed by the semi-passive RIAA equalization stage. By keeping the gain stage fully symmetrical, the Phono Box DS3 B can optimize the signal-to-noise ratio and keep interference to a minimum. For the balanced XLR outputs, a balancing stage generates a symmetrical signal, so you benefit from balanced signal transmissions again.
Note: The Phono Box DS3 B is compatible with MM (moving magnet) and MC (moving coil) cartridges. However, due to the internal wiring of MM cartridges, you'll need to upgrade your turntable with an MC cartridge to access the entirety of that balanced audio signal.
Balanced & Unbalanced Connectivity: The Pro-Ject Phono Box DS3 B is outfitted with balanced (XLR) and unbalanced (RCA) connection. There is stereo unbalanced RCA input, plus a 5-pin mini XLR balanced stereo input to connect to your turntable. There is also a stereo unbalanced RCA output, as well as a XLR balanced stereo output to connect to the corresponding unbalanced or balanced line-level input of your integrated amplifier or AV receiver. By utilizing phono preamp's 5-pin mini XLR input and stereo XLR outputs, you'll enjoy the benefits of a balanced signal path.
Note: A 5-pin mini XLR to stereo RCA cable (sold separately) is required to make connection between the Phono Box DS3 B's 5-pin mini XLR input and the stereo RCA output of your turntable.
Control Settings: The Phono Box DS3 B features various control settings to perfectly match the Phono Box DS3 B to a wide variety of phono cartridges, making sure your turntable sounds it best.
- Gain Levels: The phono preamp's gain level (40/45/60/65dB) can be adjusted to match the level of your MM/MC turntable.
- Input Impedance/Capacitance: You can adjust the phono preamp's input impedance (10 to 1,000 or 47,000 Ohms) and input capacitance (50/150/300/400 pF) to the setting that best suits your turntable.
- Subsonic Filter: A switchable subsonic filter prevents your amplifier and speakers of ultra low rumble below 20Hz (-18dB).
Note: You can connect a up to two turntables simultaneously (one via balanced and one via unbalanced), with all the control settings and parameters for each input stored in the phono box's memory.
All Metal Construction: The Phono Box DS3 B employs a steel chassis enveloped by aluminum panels. This all metal construction design offers very high rigidity and isolation against outside interferences, which is essential for phono applications. The front-panel push button controls are also made from aluminum. The Phono Box DS3 B is available in a black or silver finish.
Ground Terminal: The phono preamp also has a turntable ground, in case your turntable has a separate ground lead. This provides shielding to the tone-arm and the sensitive circuitry in the turntable.
External Power Supply: The Phono Box DS3 B is powered by an external AC adapter in order to keep all the parts which can radiate electromagnetic fields out of the amplifier range. To further ensure clean power, the included external AC power adapter uses a transformer with a very low core saturation, plus shielding between the primary and secondary windings.
Trigger In/Out: The Phono Box DS3 B offers a 12V trigger input (3.5mm) and 12V trigger output (3.5mm) so you can sync power on and off functions between the phono box, your AV receiver or integrated amplifier, and your turntable.
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Customer Q&A
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This Phono preamp meets and beats almost all demands from ones turntable. My only suggestion to the manufacturer would be to offer capacitance settings (50,100,150,200,250 and 300). Would make this device a perfect match to any system. Great add-on!
Thomas from DELAND, FL