Roland JC-120 Jazz Chorus 120 Watt Guitar Amplifier

Introduction

The Roland JC-120 Jazz Chorus is a legendary guitar amplifier, renowned for its pristine clean tone and distinctive stereo chorus effect. This manual provides essential information for setting up, operating, maintaining, and troubleshooting your JC-120 amplifier to ensure optimal performance and longevity.

Figure 1: Front view of the Roland JC-120 Jazz Chorus 120 Watt Guitar Amplifier, showcasing its classic design with two large speakers and a control panel at the top.

Setup

Unpacking and Inspection

Carefully remove the amplifier from its packaging. Retain all packing materials for future transport or storage. Inspect the amplifier for any signs of damage that may have occurred during shipping. If any damage is found, contact your dealer immediately.

What's in the Box

• JC-120 Jazz Chorus Amp
• Power Cord
• Owner's Manual (this document)

Placement

Place the amplifier on a stable, level surface. Ensure adequate ventilation around the unit to prevent overheating. Avoid placing the amplifier in direct sunlight, near heat sources, or in areas with high humidity or excessive dust.

• Dimensions (W x D x H): 32.28 x 13.78 x 25.98 inches (820 x 350 x 660 mm)
• Weight: 73.2 pounds (33.2 kg)

Connections

Before connecting any cables, ensure the amplifier's power switch is in the OFF position and the volume controls are set to minimum. Use high-quality instrument cables for optimal sound performance.

Figure 2: Rear view of the Roland JC-120 Jazz Chorus amplifier, illustrating the various input and output jacks for connecting instruments, effects, and other audio equipment.

• Instrument Input (6.35mm Jack): Connect your guitar to either the CHANNEL 1 or CHANNEL 2 input jack. The JC-120 features two independent input channels.
• Power Connection: Connect the supplied power cord to the AC IN jack on the rear panel of the amplifier, then plug it into a suitable AC outlet. Ensure the power supply matches the voltage requirements specified on the amplifier.
• External Effects Loop: The JC-120 includes a stereo effects loop (SEND/RETURN) for connecting external effects processors.
• Footswitch Jacks: Connect optional footswitches (not included) to control built-in effects like Chorus/Vibrato, Reverb, and Distortion.

Operating Instructions

Powering On/Off

1. Ensure all connections are secure and volume controls are at minimum.
2. Press the POWER switch to turn on the amplifier. The power indicator will illuminate.
3. To turn off, press the POWER switch again.

Control Panel Overview

Figure 3: Detailed view of the Roland JC-120 Jazz Chorus control panel, highlighting the independent controls for Channel 1 and Channel 2, including EQ, volume, and bright switches.

• CHANNEL 1 / CHANNEL 2: Each channel features independent controls.
  • BRIGHT Switch: Engages a high-frequency boost for a brighter tone.
  • VOLUME Knob: Adjusts the overall volume of the respective channel.
  • TREBLE / MIDDLE / BASS Knobs: Three-band equalizer for tone shaping.
• DISTORTION Knob: Controls the amount of built-in distortion. Turn clockwise for more gain.
• REVERB Knob: Adjusts the level of the authentic spring reverb effect.
• VIBRATO / CHORUS Section:
  

  Figure 4: Close-up of the Roland JC-120 Jazz Chorus's iconic Dimensional Space Chorus and Vibrato controls, including Speed, Depth, and the mode selector switch.

  • SPEED Knob: Adjusts the rate of the chorus or vibrato effect.
  • DEPTH Knob: Adjusts the intensity of the chorus or vibrato effect.
  • VIB/OFF/CHORUS Switch: Selects between Vibrato, Off, or the famous Dimensional Space Chorus effect.

Using with External Pedals

The JC-120 is widely recognized as an excellent platform for external effects pedals due to its clean headroom and stereo capabilities. Connect your stompbox pedals, multi-effects units, or amp modelers to the input or utilize the effects loop for optimal signal chain integration.

Maintenance

Cleaning

To clean the amplifier, use a soft, dry cloth. For stubborn dirt, a slightly damp cloth with mild, non-abrasive cleaner can be used, followed by a dry cloth. Do not use volatile solvents such as benzene or paint thinner, as these may damage the finish.

Storage

When not in use for extended periods, store the amplifier in a cool, dry place away from direct sunlight and extreme temperatures. Consider using an amplifier cover to protect it from dust and spills.

Troubleshooting

Specifications

• Model: JC-120
• Output Wattage: 120 Watts (60W + 60W Stereo)
• Speakers: Two 12-inch "silver cone" speakers
• Input/Output Jacks: 6.35mm Jack (Instrument In), Effects Loop (Send/Return), Line Out, Headphone Out, Footswitch Jacks
• Power Source: Corded Electric
• Material: Metal chassis
• Compatible Devices: Guitar
• Item Weight: 73.2 pounds (33.2 kg)
• Product Dimensions (W x D x H): 32.28 x 13.78 x 25.98 inches (820 x 350 x 660 mm)
• Color: Black

Warranty and Support

For warranty information and details regarding service and support, please refer to the warranty card included with your product or visit the official Roland website. For customer support inquiries, you may also contact your authorized Roland dealer.

Online Resources:

• Visit the Roland Store on Amazon
• Official Roland Website (Note: This is a general link, specific support pages may vary.)