1. Introduction
The Radial Pro48 is a high-performance 48V phantom powered active direct box engineered for instruments with passive pickups and low output levels. Its design focuses on delivering a clean, uncolored signal with extended frequency response, making it suitable for various audio applications.
1.1 Key Features
- Phantom-powered active direct box for high-resolution audio.
- Designed for low-volume instruments with passive pickups.
- Features a -15dB pad switch for managing hot input signals.
- Robust 14-gauge steel construction with a unique book-end design for durability.
- Internal welded I-beam construction protects the PC board from stress.
- Smooth, linear frequency response from 20Hz to over 100kHz.
2. Safety Information
Please read and understand all safety instructions before operating the Radial Pro48. Failure to do so may result in damage to the unit or connected equipment.
- The Pro48 requires 48V phantom power from a mixer or preamplifier to operate. It does not use batteries. Ensure phantom power is supplied to the XLR output.
- Do not expose the unit to moisture or extreme temperatures.
- Avoid dropping or subjecting the unit to severe impacts, despite its robust construction.
- Use high-quality cables to ensure optimal performance and prevent signal issues.
3. Setup
Follow these steps to properly connect your Radial Pro48:
- Connect Instrument to Input: Connect your instrument (e.g., acoustic guitar, bass with passive pickups) to the 1/4-inch INPUT jack on the Pro48 using a standard instrument cable.
- Connect to Amplifier (Optional): If you wish to send your instrument's signal to an on-stage amplifier, connect the 1/4-inch THRU jack on the Pro48 to your amplifier's input. This allows you to monitor your sound locally without affecting the signal sent to the mixer.
- Connect to Mixer/Preamp: Connect the XLR LOW-Z OUT (600Ω) jack on the Pro48 to an XLR input on your mixing console or microphone preamplifier. Ensure that 48V phantom power is enabled on the mixer channel connected to the Pro48. The Pro48 will not function without phantom power.
- Engage Pad (If Needed): If your instrument has a particularly high output level, engage the -15dB PAD switch to prevent input clipping and distortion.
- Use Ground Lift (If Needed): If you experience hum or buzz, activate the PIN-1 LIFT switch (Ground Lift). This can help eliminate ground loops between your instrument and the mixer.
4. Operating Instructions
Once connected, the Radial Pro48 operates automatically when phantom power is supplied. No additional controls are required for basic operation.
- Signal Level Management: Use the -15dB PAD switch if your instrument's output is too strong, causing distortion at the mixer input. This switch reduces the signal level before it enters the Pro48's active circuitry.
- Hum and Noise Reduction: If you encounter unwanted hum or buzz in your audio signal, toggle the PIN-1 LIFT switch. This switch disconnects the ground connection at the XLR output, which can resolve ground loop issues.
- Monitoring: The THRU output allows you to send the original instrument signal to an amplifier for personal monitoring, while the balanced XLR output sends the processed signal to the main mixing console.
5. Maintenance
The Radial Pro48 is designed for durability and requires minimal maintenance.
- Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Do not use liquid cleaners or solvents.
- Storage: Store the unit in a dry environment, away from extreme temperatures and direct sunlight.
- Durability: The Pro48 features a robust 14-gauge steel chassis and internal I-beam construction, designed to withstand the rigors of live performance and studio use. Avoid unnecessary impacts to prolong its lifespan.
6. Troubleshooting
If you encounter issues with your Radial Pro48, refer to the following common problems and solutions:
| Problem | Possible Cause | Solution |
|---|---|---|
| No sound output | No phantom power supplied. Incorrect cable connection. Faulty cable. | Ensure 48V phantom power is enabled on the mixer channel. Verify all cables are securely connected to the correct jacks. Test with a known good XLR cable. |
| Hum or Buzz | Ground loop. Poor quality cables. | Engage the PIN-1 LIFT switch. Replace low-quality or damaged cables with professional-grade ones. |
| Distorted sound | Input signal too hot. Faulty cable. | Engage the -15dB PAD switch. Check instrument output level. Test with a different instrument cable. |
7. Specifications
- Model: Pro48
- Part Number: R8001105
- Audio Circuit Type: Proprietary analog circuit with low-noise op-amp
- Input Voltage: 48 Volts (DC) phantom power required
- Frequency Response: 20Hz to over 100kHz
- Signal-to-Noise Ratio: 99 dB
- Input Connectivity: 1/4-inch TS unbalanced
- Output Connectivity: XLR balanced (Low-Z Out), 1/4-inch TS unbalanced (Thru)
- Pad: -15dB switchable
- Ground Lift: Pin-1 Lift switch
- Construction: 14-gauge steel chassis, internal welded I-beam
- Dimensions: 6.4 x 4.3 x 3 inches (16.26 x 10.92 x 7.62 cm)
- Weight: 1.23 pounds (0.56 kg)
8. Warranty and Support
8.1 Warranty Information
The Radial Pro48 includes a Three Year Limited Warranty, which is transferable. Please retain your proof of purchase for warranty claims.
8.2 Customer Support
For technical assistance, troubleshooting beyond this manual, or warranty inquiries, please visit the official Radial Engineering website or contact their customer support directly. Contact information can typically be found on the manufacturer's website or product packaging.
