Midas MICROPHONE PREAMPLIFIER 502 User Manual

1. Introduction

The Midas MICROPHONE PREAMPLIFIER 502 is a high-performance, compact 500 Series premium microphone/line preamplifier. It incorporates award-winning Midas amplifier technology, enhanced with quad discrete ultra low noise input transistors, delivering exceptional audio fidelity.

This module features the legendary Midas input, allowing signal levels up to +24 dBu without the need for a pad, while maintaining its much-loved soft clipping characteristic. It also includes classic Midas XL4 swept low and high pass filters with independent selection switches, providing precise tonal shaping. A switchable twin aux balanced output offers mic/line splitter capability when installed in compatible Midas L6 or L10 racks.

Figure 1.1: Front view of the Midas MICROPHONE PREAMPLIFIER 502, highlighting its input, gain, filter, and output controls.

2. Important Safety Instructions

Please read these instructions carefully before operating your Midas MICROPHONE PREAMPLIFIER 502. Keep this manual for future reference.

• Do not expose this apparatus to rain or moisture.
• Do not block any ventilation openings. Install in accordance with the manufacturer's instructions.
• Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat.
• Only use attachments/accessories specified by the manufacturer.
• Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
• This product is designed for professional audio applications and should be installed by qualified personnel.

3. What's in the Box

Upon unpacking your Midas MICROPHONE PREAMPLIFIER 502, please ensure all components are present and in good condition:

• Midas MICROPHONE PREAMPLIFIER 502 module
• Quick Start Guide / Safety Information
• Warranty Registration Card

If any items are missing or damaged, please contact your dealer immediately.

4. Setup

The Midas MICROPHONE PREAMPLIFIER 502 is a 500 Series module designed to be installed into a compatible 500 Series rack or chassis (e.g., Midas L6 or L10 racks).

4.1 Installation into a 500 Series Rack

1. Ensure your 500 Series rack is powered off and disconnected from the mains supply.
2. Carefully align the edge connector of the 502 module with an available slot in your 500 Series rack.
3. Gently but firmly push the module into the slot until it is fully seated. Do not force the module.
4. Secure the module to the rack using the provided screws (typically two per module) through the faceplate.
5. Once all modules are installed, reconnect your 500 Series rack to the mains supply and power it on.

Figure 4.1: Angled view of the Midas MICROPHONE PREAMPLIFIER 502, illustrating its form factor for 500 Series rack installation.

4.2 Audio Connections

The 502 module receives its input and sends its output via the 500 Series rack's backplane connections. Refer to your 500 Series rack's manual for specific input/output patching details.

• Microphone/Line Input: Connect your microphone or line-level source to the corresponding input on your 500 Series rack's rear panel.
• Output: Connect the output of your 500 Series rack to your mixing console, audio interface, or other processing equipment.
• Aux Output (if applicable): If using a Midas L6 or L10 rack, the switchable twin aux balanced output provides additional routing flexibility.

5. Operating the Midas 502

The Midas 502 offers intuitive controls for precise microphone and line-level signal conditioning.

5.1 Front Panel Controls

• INPUT (Rotary Knob): Adjusts the input level of the signal. The meter above indicates the input signal level.
• GAIN (Rotary Knob): Controls the amount of amplification applied to the input signal.
• LOW PASS (Rotary Knob): Swept low pass filter control, allowing you to cut high frequencies. Range: 3 kHz to 15 kHz.
• HIGH PASS (Rotary Knob): Swept high pass filter control, allowing you to cut low frequencies. Range: 10 Hz to 400 Hz.
• TRIM (Rotary Knob): Fine-tunes the output level of the preamplifier. The meter above indicates the output signal level.
• 48V (Button): Engages +48V phantom power for condenser microphones. An indicator light illuminates when active.
• IN (Button - Phase): Inverts the phase of the input signal (180 degrees). An indicator light illuminates when active.
• IN (Button - Filter Bypass): Bypasses the low and high pass filters. An indicator light illuminates when active.
• TX (Button): Activates the transformer output, providing a distinct sonic character. An indicator light illuminates when active.
• Mic/Line (Switch): Selects between microphone and line-level input impedance and gain staging.

Figure 5.1: Detailed view of the Midas MICROPHONE PREAMPLIFIER 502 front panel controls.

5.2 Basic Operation Workflow

1. Connect your microphone or line source to the appropriate input on your 500 Series rack.
2. Set the Mic/Line switch according to your source.
3. If using a condenser microphone, engage the 48V phantom power.
4. Start with the GAIN and INPUT knobs at their minimum settings.
5. Gradually increase the GAIN until you achieve a healthy signal level on the input meter, avoiding clipping.
6. Adjust the LOW PASS and HIGH PASS filters as needed to shape the tone and remove unwanted frequencies.
7. Use the IN (Phase) button if phase correction is required.
8. Engage the TX button for transformer coloration if desired.
9. Use the TRIM knob to fine-tune the output level to your next device in the signal chain.

6. Maintenance

The Midas MICROPHONE PREAMPLIFIER 502 is designed for reliable operation with minimal maintenance.

• Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Do not use abrasive cleaners or solvents.
• Ventilation: Ensure that the ventilation slots on your 500 Series rack are not obstructed to prevent overheating.
• Storage: When not in use for extended periods, store the module in a cool, dry place, ideally within its original packaging or a protective case.

7. Troubleshooting

If you encounter issues with your Midas MICROPHONE PREAMPLIFIER 502, refer to the following common troubleshooting steps:

If the problem persists after trying these steps, please contact Midas customer support or an authorized service center.

8. Specifications

Figure 8.1: Rear view of the Midas MICROPHONE PREAMPLIFIER 502, displaying manufacturing and serial information.

9. Warranty and Support

Midas products are built to the highest standards and come with a limited warranty. Please refer to the warranty card included with your product or visit the official Midas website for detailed warranty terms and conditions.

For technical support, service, or spare parts, please contact your authorized Midas dealer or visit the Midas support page online. When contacting support, please have your product model number (MICROPHONE PREAMPLIFIER 502) and serial number ready.

Official Midas Website: www.midasconsoles.com