Warm Audio WA12 MKII Single Channel Microphone Preamplifier & Instrument DI User Manual

1. Introduction

Thank you for purchasing the Warm Audio WA12 MKII Single Channel Microphone Preamplifier & Instrument DI. This unit is a completely discrete, high voltage, dual-transformer microphone preamplifier designed to enhance the tone of microphones and instruments. It offers high gain (+71dB), high headroom, and low noise, making it an ideal choice for a wide range of recording applications. This manual will guide you through the setup, operation, and maintenance of your WA12 MKII to ensure optimal performance and longevity.

2. Safety Instructions

Please read and follow all safety instructions before operating this device. Keep this manual for future reference.

• Power Source: Only use the provided IEC cable and connect to a grounded power outlet. Ensure the voltage matches the unit's requirements.
• Water & Moisture: Do not expose this unit to rain, moisture, or any liquids. Do not operate near water.
• Heat: Do not place the unit near heat sources such as radiators, heat registers, stoves, or other apparatus that produce heat.
• Ventilation: Ensure proper ventilation. Do not block any ventilation openings.
• Servicing: Do not attempt to service this unit yourself. 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.
• Cleaning: Clean only with a dry cloth.

3. Package Contents

Your Warm Audio WA12 MKII package should include the following items:

• Warm Audio WA12 MKII Unit
• IEC Cable
• Owners Manual

4. Product Overview

4.1 Front Panel Controls

Image: Front panel of the Warm Audio WA12 MKII, showing all controls and indicators.

• 1/4" Instrument DI Input: Connect high-impedance instruments such as guitars or basses here.
• HI-Z Button: Engages the high-impedance input for instruments, optimizing the signal path.
• 48V Button: Activates +48V phantom power for condenser microphones. An indicator LED illuminates when active.
• PAD Button: Applies a -20dB attenuation to the input signal, useful for very loud sources to prevent clipping.
• POL (Polarity) Button: Inverts the polarity (phase) of the input signal. Useful for correcting phase issues when using multiple microphones.
• TONE Button: Engages a tone-shaping circuit that alters the input impedance from 600 ohms to 150 ohms, providing a different sonic character.
• GAIN Knob: Controls the input gain for the microphone or instrument signal, ranging from 29dB to 65dB.
• OUTPUT Knob: Adjusts the overall output level of the preamplifier.
• VU Meter LEDs: A series of LEDs indicating the output level, ranging from -20dB to +18dB, with indicators for 0dB, +08dB, and +18dB (clipping).
• POWER Button: Turns the unit on or off. An indicator LED illuminates when the unit is powered on.

4.2 Rear Panel Connections

The rear panel of the WA12 MKII provides the necessary connections for integrating the unit into your audio setup.

• XLR Microphone Input: Connect your microphone via a standard XLR cable.
• XLR Line Output: Connect this output to your audio interface, mixer, or other recording equipment.
• IEC Power Input: Connect the provided IEC cable here to power the unit.

5. Setup

Follow these steps to set up your Warm Audio WA12 MKII:

1. Power Connection: Connect the IEC power cable to the rear panel of the WA12 MKII and then to a grounded AC power outlet.
2. Microphone Connection: Connect your microphone to the XLR Microphone Input on the rear panel using a high-quality XLR cable.
3. Instrument Connection (Optional): If using an instrument, connect it to the 1/4" Instrument DI Input on the front panel. Ensure the HI-Z button is engaged.
4. Output Connection: Connect the XLR Line Output on the rear panel to an input on your audio interface, mixer, or other recording device.
5. Power On: Press the POWER button on the front panel. The power indicator LED will illuminate.
6. Initial Settings: Set the GAIN and OUTPUT knobs to their minimum positions before connecting any audio sources to avoid sudden loud signals.

6. Operating Instructions

Operating the WA12 MKII involves adjusting its various controls to achieve the desired sound and level.

• Gain Staging: Begin by slowly increasing the GAIN knob until the desired input level is achieved. Monitor the VU Meter LEDs to ensure the signal is not clipping (red +18dB LED). Adjust the OUTPUT knob to control the signal level sent to your recording device.
• Phantom Power (48V): If using a condenser microphone, press the 48V button to supply phantom power. Always connect the microphone before engaging phantom power and disengage it before disconnecting the microphone.
• Pad: For very loud sources (e.g., close-miked drums, loud guitar amps), engage the PAD button to reduce the input signal by 20dB, preventing distortion.
• Polarity (POL): Use the POL button to invert the phase of the input signal. This can be crucial when recording with multiple microphones to avoid phase cancellation issues.
• Tone: The TONE button changes the input impedance, offering a different sonic flavor. Experiment with this setting to find what best suits your microphone and source.
• HI-Z: When connecting an instrument directly to the 1/4" input, ensure the HI-Z button is engaged for proper impedance matching.

7. Maintenance

Proper maintenance will ensure the longevity and optimal performance of your WA12 MKII.

• Cleaning: Use a soft, dry cloth to clean the exterior of the unit. Avoid abrasive cleaners or solvents.
• Storage: When not in use, store the unit in a cool, dry place away from direct sunlight and extreme temperatures.
• Ventilation: Ensure the unit has adequate airflow around it during operation to prevent overheating.
• Cable Care: Handle all cables with care. Avoid bending or crimping them excessively.

8. Troubleshooting

If you encounter any issues with your WA12 MKII, refer to the following common problems and solutions:

• No Power:
  • Check if the IEC cable is securely connected to the unit and the power outlet.
  • Ensure the power outlet is functional.
  • Verify the POWER button is pressed in and its LED is illuminated.
• No Sound:
  • Check all audio cable connections (microphone, instrument, output).
  • Ensure GAIN and OUTPUT knobs are not set to minimum.
  • If using a condenser mic, ensure 48V phantom power is engaged.
  • If using an instrument, ensure the HI-Z button is engaged.
  • Check the input/output settings on your audio interface or mixer.
• Distorted Sound:
  • Reduce the GAIN knob.
  • Engage the PAD button if the source is very loud.
  • Check the input level on your recording device to ensure it's not clipping.
• Hum or Noise:
  • Ensure all cables are properly shielded and connected.
  • Try a different power outlet.
  • Check for ground loops.
  • Ensure the POL (Polarity) button is set correctly if using multiple mics.

If the problem persists, contact Warm Audio support or a qualified technician.

9. Specifications

10. Warranty Information

Warm Audio products are designed and manufactured to the highest quality standards. This product is covered by a limited warranty against defects in materials and workmanship for a period specified by Warm Audio at the time of purchase. Please retain your proof of purchase for warranty claims. For specific warranty terms and conditions, please refer to the official Warm Audio website or contact their customer support.

11. Support

For technical support, product registration, or further inquiries, please visit the official Warm Audio website or contact their customer service department. You can find contact information and FAQs on their support page.