Introduction
Thank you for choosing the Pro-Ject Phono Box DS3 B. This balanced phono preamplifier is designed to provide high-quality amplification for both Moving Magnet (MM) and Moving Coil (MC) cartridges, offering flexible adjustments for optimal sound reproduction. Please read this manual carefully to ensure proper setup and operation.
Safety Instructions
- Always disconnect the power adapter from the mains before handling the device or connecting/disconnecting cables.
- Ensure the power supply voltage matches the requirements specified on the device.
- Avoid exposing the device to moisture, rain, or excessive heat.
- Do not open the device casing. Refer all servicing to qualified personnel.
- Keep the device away from sources of strong electromagnetic interference.
Package Contents
Verify that your package contains the following items:
- Pro-Ject Phono Box DS3 B unit
- 18V DC power adapter
- User Manual
Product Overview
Front Panel Controls
Figure 1: Front panel of the Pro-Ject Phono Box DS3 B.
- Loading Ohms (Variable Potentiometer): Adjusts the input impedance for Moving Coil (MC) cartridges continuously from 10 to 1000 Ohms.
- Input Selector: Toggles between RCA and XLR input connections.
- Subsonic Filter: Activates a filter to remove very low-frequency rumble, improving sound clarity.
- Loading pF: Selects input capacitance for Moving Magnet (MM) cartridges (50, 150, 300, 400 pF).
- Gain dB: Adjusts the gain level (40, 45, 50, 55, 60, 65 dB) to match your cartridge output and amplifier input sensitivity.
Rear Panel Connections
Figure 2: Rear panel connections of the Pro-Ject Phono Box DS3 B.
- Inputs (RCA & 5-pin mini XLR): Connect your turntable's output cables here. The 5-pin mini XLR allows for a true balanced connection from compatible turntables.
- Outputs (RCA & XLR): Connect these to your amplifier or receiver's line-level inputs. XLR outputs provide a balanced signal.
- Ground Terminal: Connect your turntable's ground wire here to minimize hum.
- Trigger Input/Output (12V): For remote power control with other compatible Pro-Ject components.
- 18V DC Power Input: Connect the supplied power adapter here.
Setup
Placement
Place the Phono Box DS3 B on a stable, level surface, away from heat sources and other electronic devices that may cause interference. Ensure adequate ventilation around the unit.
Connecting Your Turntable
- RCA Connection: Connect the RCA cables from your turntable to the RCA inputs on the Phono Box DS3 B.
- Balanced Connection (5-pin mini XLR): If your turntable supports balanced output, connect a compatible 5-pin mini XLR cable from your turntable to the balanced input on the Phono Box DS3 B.
- Grounding: Connect the ground wire from your turntable to the ground terminal on the Phono Box DS3 B. This is crucial for minimizing hum and noise.
Connecting to Your Amplifier
- RCA Output: Connect RCA cables from the Phono Box DS3 B's RCA outputs to a line-level input (e.g., 'Aux', 'Line In', 'CD') on your amplifier or receiver. Do not connect to a 'Phono' input on your amplifier, as this would result in double pre-amplification.
- XLR Output: For a balanced connection, connect XLR cables from the Phono Box DS3 B's XLR outputs to balanced XLR inputs on your amplifier or receiver.
Power Connection
Connect the supplied 18V DC power adapter to the 'Power 18V' input on the rear panel of the Phono Box DS3 B. Then, plug the power adapter into a suitable mains outlet. Only use the power adapter supplied with the unit.
Figure 3: Example setup showing the Phono Box DS3 B connected to a turntable.
Operating
Once all connections are made, you can power on the Phono Box DS3 B. The unit does not have a dedicated power switch; it powers on when connected to the mains. Adjust the settings on the front panel according to your cartridge type and listening preferences.
Input Selection
Use the 'Input' button to select between the RCA or XLR input, depending on how your turntable is connected.
Adjusting Load Impedance (MC Cartridges)
For Moving Coil (MC) cartridges, use the 'Loading Ohms' potentiometer to continuously adjust the input impedance. Experiment with different settings while listening to find the optimal sound for your specific MC cartridge. This adjustment can significantly impact the tonal balance and dynamics.
Adjusting Capacitance (MM Cartridges)
For Moving Magnet (MM) cartridges, use the 'Loading pF' buttons to select the appropriate input capacitance (50, 150, 300, or 400 pF). Refer to your cartridge manufacturer's recommendations for the ideal capacitance setting.
Adjusting Gain
Use the 'Gain dB' buttons to select the appropriate gain level (40, 45, 50, 55, 60, or 65 dB). This should be set to match the output voltage of your cartridge and the input sensitivity of your amplifier. Higher gain settings are typically used for low-output MC cartridges.
Using the Subsonic Filter
Press the 'Subsonic' button to activate the subsonic filter. This filter helps to remove very low-frequency noise and rumble (e.g., from warped records or turntable motor vibrations) that can cause woofer pumping and muddy bass without affecting the audible frequency range.
Maintenance
The Pro-Ject Phono Box DS3 B requires minimal maintenance.
- Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Do not use liquid cleaners or solvents, as they may damage the finish.
- Storage: If storing the unit for an extended period, disconnect it from the power supply and store it in a cool, dry place.
Troubleshooting
If you encounter issues, refer to the following troubleshooting guide:
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound | Incorrect connections, wrong input selected, amplifier input not selected. | Check all cable connections. Ensure the correct input (RCA/XLR) is selected on the Phono Box DS3 B and the correct input is selected on your amplifier. |
| Humming or buzzing noise | Grounding issue, proximity to other electronics, faulty cables. | Ensure the turntable's ground wire is securely connected to the Phono Box DS3 B. Move the unit away from other electronic devices. Try different cables. |
| Distorted sound | Incorrect gain setting, incorrect loading (impedance/capacitance). | Adjust the 'Gain dB' setting. Verify 'Loading Ohms' (MC) or 'Loading pF' (MM) settings match your cartridge specifications. |
| Weak or low volume | Insufficient gain setting. | Increase the 'Gain dB' setting. |
Specifications
- Model: Pro-Ject Phono Box DS3 B (PJ829351)
- Input Impedance (MC): 10 - 1000 Ohms (continuously variable)
- Input Capacitance (MM): 50, 150, 300, 400 pF
- Gain: 40, 45, 50, 55, 60, 65 dB
- Inputs: RCA, 5-pin mini XLR (balanced)
- Outputs: RCA, XLR (balanced)
- Subsonic Filter: Yes
- Dimensions (L x W x H): 8.11 x 8.07 x 2.83 inches (20.6 x 20.5 x 7.2 cm)
- Weight: 1480 Grams (3.26 lbs)
- Material: Alloy Steel chassis
- Power Supply: 18V DC (external power adapter)
- Key Features: Fully discrete audio circuitry, fully symmetrical gain stage, split passive RIAA EQ, dual mono design, true balanced connection capability.
Figure 4: Internal view of the Phono Box DS3 B, highlighting its discrete audio circuitry.
Warranty and Support
This Pro-Ject Phono Box DS3 B comes with a 2-year manufacturer's warranty from the date of purchase. Please retain your proof of purchase for warranty claims.
For technical support, service, or further information, please visit the official Pro-Ject Audio Systems website or contact your authorized dealer.
You can also find more information and support on the Pro-Ject Audio Systems Store on Amazon.
