Rodyweil RO-04 Pro Mic Preamp Instruction Manual

1. Introduction

The Rodyweil RO-04 Pro Mic Preamp is a versatile audio device designed to amplify and condition signals from various microphones and instruments. It provides up to 72dB of clean gain, ensuring optimal signal levels for recording and live sound applications. This manual outlines the proper setup, operation, and maintenance procedures to ensure the RO-04 performs as intended.

2. Safety Information

Please read and understand the following safety precautions before operating the Rodyweil RO-04 Pro Mic Preamp:

• Do not expose the unit to water or excessive moisture.
• Avoid placing the unit near heat sources or in direct sunlight.
• Use only the specified 5V 1A USB-C power supply.
• Do not attempt to open or service the unit. Refer all servicing to qualified personnel.
• Ensure proper ventilation around the unit during operation.

3. Package Contents

Verify that all items are present in the package:

• Rodyweil RO-04 Pro Mic Preamp Unit
• USB-C Power Cable
• XLR Cable
• Instruction Manual (this document)

4. Product Overview

4.1. Front Panel Controls

• MIC GAIN Knob: Adjusts the gain level for the XLR microphone input from 0dB to 66dB in stepped increments.
• TRIM (LAVALIER) Knob: Provides fine-tuning of the microphone gain (-6dB to +6dB) and controls the gain for the lavalier input (0-50dB).
• HI-Z GAIN Knob: Adjusts the gain level for the 1/4" instrument input from +10dB to +50dB.
• +48V Button: Activates 48V phantom power for condenser microphones. An indicator light confirms activation.
• HPF Button: Engages a High-Pass Filter at 100Hz to reduce low-frequency rumble and unwanted noise. An indicator light confirms activation.
• PHASE Button: Inverts the phase of the input signal by 180 degrees, useful for correcting phase issues. An indicator light confirms activation.

4.2. Rear Panel Connections

• ON/OFF Switch: Powers the unit on or off.
• POWER (5V 1A) USB-C Port: Connects to a 5V 1A USB-C power source.
• LINE OUT (XLR): Balanced XLR output for connecting to audio interfaces, mixers, or other line-level equipment. Output level: +4dBu.
• LINE OUT (1/8"): Unbalanced 1/8" (3.5mm) output for connecting to consumer-level audio equipment. Output level: -10dBV.
• HI-Z (1/4") Input: 1/4" TS input for connecting high-impedance instruments like guitars and basses.
• LAVALIER IN (1/8") Input: 1/8" (3.5mm) input for connecting unbalanced lavalier microphones. A +10dB button is available for additional gain.
• MIC IN (XLR) Input: Balanced XLR input for connecting dynamic, condenser, or ribbon microphones.

5. Features

• 72dB Clean Gain: The RO-04 provides up to 72dB of amplification, making it suitable for low-output microphones such as dynamic and ribbon types, ensuring a strong and clear signal.
• Ultra-Low Noise Performance: With an Equivalent Input Noise (EIN) as low as -120dB, the preamp maintains a clean and hiss-free signal, preserving audio clarity even at high gain settings.
• High Fidelity Audio: A Total Harmonic Distortion (THD) of 0.0035% at 1kHz ensures accurate and transparent audio reproduction without unwanted coloration.
• Independent Inputs: Dedicated high-impedance (Hi-Z) and microphone input stages allow for simultaneous connection and independent gain control of instruments and microphones.
• Precise Gain Control: The 11-step detented gain switch combined with a trim control offers smooth and accurate gain adjustments across the entire range, minimizing noise spikes.
• Portable Power: The unit can be powered via a standard USB-C (5V 1A) connection, enabling use with power banks for mobile recording setups.

6. Setup

Follow these steps to set up your Rodyweil RO-04 Pro Mic Preamp:

1. Connect Input Source:
   • For microphones, connect an XLR cable from your microphone to the MIC IN (XLR) port on the rear panel.
   • For instruments (e.g., guitar, bass), connect a 1/4" TS cable from your instrument to the HI-Z (1/4") port.
   • For lavalier microphones, connect a 1/8" TS/TRS cable to the LAVALIER IN (1/8") port.
2. Connect Output: Connect an XLR cable from the LINE OUT (XLR) port or a 1/8" cable from the LINE OUT (1/8") port to the line input of your audio interface, mixer, or recording device.
3. Connect Power: Connect the supplied USB-C power cable to the POWER (5V 1A) port on the rear panel and plug the other end into a compatible USB power adapter or power bank.
4. Power On: Flip the ON/OFF switch on the rear panel to the 'ON' position.
5. Initial Gain Settings: Before adjusting the RO-04's gain, ensure that the input gain on your connected audio interface or mixer is set to its minimum level. This prevents signal clipping and allows for precise gain staging with the RO-04.

7. Operating Instructions

Once the RO-04 is set up, follow these guidelines for operation:

• Adjusting Microphone Gain: Use the MIC GAIN knob to set the primary gain level for your microphone. For fine adjustments, use the TRIM (LAVALIER) knob. Aim for a strong signal without clipping.
• Adjusting Instrument Gain: Use the HI-Z GAIN knob to set the appropriate gain level for your instrument.
• Phantom Power (+48V): If using a condenser microphone, press the +48V button to supply phantom power. Ensure dynamic and ribbon microphones do not receive phantom power unless specifically designed to handle it.
• High-Pass Filter (HPF): Press the HPF button to activate the 100Hz high-pass filter. This is useful for reducing low-frequency rumble from stages, air conditioning, or vocal plosives.
• Phase Inversion: If you encounter phase cancellation issues when combining multiple microphones or signals, press the PHASE button to invert the signal's polarity.

8. Usage Considerations

8.1. Compatible Input Devices

The Rodyweil RO-04 is designed to work with a variety of audio input sources:

• Dynamic Microphones (e.g., Shure SM58, SM7B)
• Condenser Microphones (requires +48V phantom power)
• Ribbon Microphones
• Electric Guitars and Basses (via Hi-Z input)
• Lavalier Microphones

8.2. Incompatible Output Devices

The RO-04 provides a line-level output. It is not designed to directly drive devices that require a speaker-level or instrument-level input. Therefore, it should not be connected directly to:

• Guitar Amplifiers
• Audio Amplifiers (without a line-level input)
• Passive Speakers
• Interfaces designed exclusively for mobile phones (unless they specifically accept line-level input)

Always connect the RO-04's line output to a device with a dedicated line input, such as an audio interface or mixer.

9. Maintenance

To ensure the longevity and optimal performance of your Rodyweil RO-04:

• 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 cool, dry place away from direct sunlight and extreme temperatures.
• Cable Care: Handle cables carefully. Avoid sharp bends or excessive pulling that could damage connectors or wiring.

10. Troubleshooting

If you encounter issues with your Rodyweil RO-04, refer to the following common problems and solutions:

• No Power:
  • Ensure the USB-C power cable is securely connected to both the unit and the power source.
  • Verify that the power source (USB adapter or power bank) is functioning correctly and providing 5V 1A.
  • Check that the ON/OFF switch on the rear panel is in the 'ON' position.
• No Sound Output:
  • Confirm that the input source (microphone/instrument) is properly connected and functioning.
  • Check all cable connections between the RO-04 and your audio interface/mixer.
  • Ensure the MIC GAIN, TRIM, or HI-Z GAIN knobs are not set to minimum.
  • If using a condenser microphone, verify that +48V phantom power is activated.
  • Check the input selection and gain settings on your audio interface or mixer.
• Distorted Sound:
  • Reduce the MIC GAIN, TRIM, or HI-Z GAIN on the RO-04.
  • Reduce the input gain on your connected audio interface or mixer.
  • Ensure that the input signal from your microphone or instrument is not excessively loud.
• Excessive Noise/Hiss:
  • Ensure all cables are properly shielded and in good condition.
  • Check for ground loops. Try connecting all audio equipment to the same power strip.
  • Activate the HPF button to reduce low-frequency rumble.
  • Verify that gain levels are set appropriately and not excessively high for the input source.

11. Specifications

12. RO-04 vs. RO-03 Comparison

The Rodyweil RO-04 offers several enhancements over its predecessor, the RO-03, providing improved control and performance for professional audio applications.

13. Warranty and Support

For warranty information and technical support, please refer to the Rodyweil official website or contact your authorized dealer. Keep your purchase receipt as proof of purchase for warranty claims.