MXR Phase 90 Guitar Effects Pedal Instruction Manual

1. Overview

The MXR Phase 90 is a classic analog phase shifter pedal designed for electric guitars and other instruments. It is renowned for its rich, warm analog tone, capable of adding shimmery velocity and dramatic swooshing effects to your sound. This pedal features a simple, single-knob control for ease of use and has been a staple on countless professional and amateur pedalboards for decades.

Figure 1: Front view of the MXR Phase 90 pedal, showing the single 'Speed' knob, MXR logo, and footswitch.

Key Features:

• Rich, warm analog tone.
• Adds shimmery velocity and dramatic swooshing to your tone.
• Timeless phase shifter used on many classic recordings.
• Simple single-knob 'Speed' control.
• Durable metal casing.

2. Setup

Follow these steps to properly set up your MXR Phase 90 pedal:

1. Power Supply: The Phase 90 can be powered by a single 9-volt battery or an optional ECB003 AC Adapter. If using a battery, ensure it is properly installed in the battery compartment (typically accessed by removing the bottom plate). If using an AC adapter, connect it to the 9V DC input jack on the side of the pedal.


Figure 2: Side view of the pedal, highlighting the 9V DC power input jack.

2. Input Connection: Connect your guitar (or other instrument) to the 'INPUT' jack on the right side of the pedal using a standard 1/4-inch instrument cable.
3. Output Connection: Connect the 'OUTPUT' jack on the left side of the pedal to your amplifier's input (or the next pedal in your signal chain) using another standard 1/4-inch instrument cable.

Figure 3: Top view of the pedal, showing the 'INPUT' and 'OUTPUT' jacks for signal connection.
4. Placement: Place the pedal on a stable surface or integrate it into your pedalboard.

3. Operating the Pedal

The MXR Phase 90 is designed for straightforward operation with its single control knob.

Controls:

• SPEED Knob: This is the only control on the pedal. It adjusts the rate of the phasing effect. Turning the knob clockwise increases the speed of the phase sweep, resulting in a faster, more intense modulation. Turning it counter-clockwise slows down the sweep, creating a more subtle and gradual effect.
• Footswitch: Press the footswitch to engage or bypass the effect. The red LED indicator will illuminate when the effect is active.

Usage Tips:

• Experiment with the 'Speed' knob to find the desired modulation rate for your music.
• Place the Phase 90 before or after distortion/overdrive pedals in your signal chain to achieve different tonal characteristics.

4. Maintenance

Proper maintenance will ensure the longevity and optimal performance of your MXR Phase 90 pedal.

• Cleaning: Use a soft, dry cloth to clean the pedal's exterior. Avoid abrasive cleaners or solvents.
• Storage: Store the pedal in a cool, dry place away from direct sunlight and extreme temperatures.
• Battery Replacement: If using battery power, replace the 9V battery when the LED indicator dims or the effect weakens. Disconnect input/output cables before opening the battery compartment.
• Cable Connections: Periodically check all cable connections for tightness and ensure cables are not frayed or damaged.

5. Troubleshooting

If you encounter issues with your MXR Phase 90, refer to the following common troubleshooting steps:

• No Sound:
  • Ensure all cables are securely connected to the correct input/output jacks.
  • Check the power supply. If using a battery, replace it. If using an AC adapter, ensure it is properly plugged in and functioning.
  • Test the pedal with different cables, guitar, and amplifier to isolate the problem.
• Weak or Distorted Effect:
  • Check the power supply; a weak battery can cause degraded performance.
  • Ensure the 'Speed' knob is not set to an extreme position that might produce an undesirable sound.
• Unwanted Noise:
  • Ensure you are using a regulated 9V DC power supply if not using a battery.
  • Check for ground loops in your setup.
  • Ensure all cables are shielded and in good condition.

6. Specifications

7. Warranty and Support

For warranty information and technical support, please refer to the official MXR website or contact the retailer from whom you purchased the product. Keep your proof of purchase for any warranty claims. Specific warranty terms and conditions may vary by region.