Boss ME-20B Bass Multiple Effects User Manual

Content

Boss ME-20B Bass Multiple Effects Manual

Introduction to the Boss ME-20B Bass Multiple Effects

The Boss ME-20B Bass Multiple Effects is a compact multi-effects pedal designed specifically for electric bass. It combines essential bass effects, practical foot control, patch storage, and flexible connectivity in a single floor-based unit. Its straightforward pedal layout makes it suitable for rehearsals, live performances, home recording, and practice sessions where quick access to several sounds is essential.

The unit provides dedicated footswitches for sound effects, compression, and delay, along with an expression pedal for real-time control. This arrangement lets players switch effects without reaching down to adjust controls, while the two-character LED display provides a simple way to identify selected patches and settings. Thirty user patches can be stored for organizing sounds by song, playing style, or performance set.

Battery operation is a useful feature for portable practice and locations where mains power is inconvenient. The AUX IN connection allows an external music player to be used for play-along practice, and the headphone output supports quieter sessions. Stereo outputs also provide flexible connection to an amplifier, mixer, audio interface, or other compatible equipment.

This bass multi-effects pedal is best suited to beginners, gigging musicians, students, and players who prefer hands-on controls over menu-heavy editing. It is also a practical backup unit for rehearsals and performances. Players seeking modern app control, USB audio, extensive routing, or highly detailed studio editing may need a newer processor with those features.

Boss ME-20B Specifications and Features

Product type: Bass multi-effects processor with integrated foot control.
Patch memory: 30 user patches.
Audio conversion: 24-bit analog-to-digital conversion using AF method and 24-bit digital-to-analog conversion.
Sampling frequency: 44.1 kHz.
Nominal input level: INPUT -10 dBu; AUX IN -18 dBu.
Input impedance: INPUT 1 MΩ; AUX IN 22 kΩ.
Nominal output level: -10 dBu.
Output impedance: 2 kΩ.
Display: Two-character, seven-segment LED display.
Main controls: SFX/1, COMP/2, DELAY/3, and expression pedals.
Connections: 1/4-inch input, stereo miniature AUX IN, left/mono and right outputs, 1/4-inch headphones, TRS footswitch jack, and AC adapter input.
Power: Six AA batteries or an optional BOSS PSA-series AC adapter.
Current draw: Approximately 90 mA.
Approximate battery life: Up to 13 hours with alkaline batteries under stated test conditions; actual life varies.
Dimensions: 294 × 179 × 54 mm.
Weight: Approximately 1.6 kg including batteries.

How to Set Up the Boss ME-20B

Turn the amplifier or mixer volume down and switch off connected equipment.
Install six AA batteries if portable operation is required, or connect a compatible BOSS PSA-series adapter to the AC adapter jack.
Connect the bass to the INPUT jack using a suitable 1/4-inch instrument cable.
Connect OUTPUT L/MONO to a bass amplifier or the left input of a mixer. Use both left and right outputs only when stereo operation is required.
For silent practice, connect headphones to the PHONES jack. Use an appropriate adapter if the headphone plug does not match the jack.
For play-along practice, connect a music player to AUX IN and set its volume low before gradually increasing it.
Switch on the amplifier or mixer, then activate the ME-20B. Raise the volume slowly and select a patch.
Use the SFX/1, COMP/2, and DELAY/3 pedals to control their assigned effect sections. Move the expression pedal to adjust its assigned parameter.
When connecting an optional external footswitch, use the correct cable and compatible BOSS footswitch model.

Keep the unit dry, use only the specified power source, and disconnect power before installing batteries. Avoid placing it near heat, moisture, strong vibration, or unstable surfaces. If there is no sound, check the cable order, patch volume, amplifier input, and battery condition before increasing levels.

Boss ME-20B Troubleshooting Guide

No sound

Confirm that the bass is connected to INPUT and the amplifier or mixer is connected to OUTPUT L/MONO. Test another cable, check the amplifier input selection, and verify that the master volume is raised. If battery power is being used, install a fresh set of six AA batteries.

Sound is distorted or unusually noisy

Lower the bass volume temporarily and check whether the input signal is overloading connected equipment. Try a different power source, move audio cables away from power adapters, and remove unnecessary connections. Excessive effect gain or compression can also increase noise, so compare the affected patch with a basic patch.

Effects do not respond as expected

Check the selected patch and confirm that the relevant effect section is enabled. The expression pedal may control a parameter only when assigned within the selected sound. Move the pedal through its full range and inspect it for physical obstruction.

AUX IN or headphones are silent

Confirm that the external player is operating, its output volume is raised, and the correct stereo cable is being used. For headphones, check the plug size and insert it fully. Headphone output level may also depend on the connected device and selected settings.

Display or power problems

Disconnect the adapter, remove the batteries, wait briefly, and reconnect one power source. Do not combine incompatible adapters or use batteries showing leakage or damage. The ME-20B does not require users to diagnose numbered error codes; persistent faults should be handled by an authorized BOSS or Roland service center. Consult the official owner’s manual and regional support service for repair guidance and warranty terms.

Boss ME-20B Pros and Cons

Advantages

Bass-focused design: The unit is built for bass signal levels and provides a practical selection of effects for common playing situations.
Hands-on operation: Dedicated pedals and physical controls are quicker to understand than deeply nested menus.
Portable power: Six AA batteries allow operation away from a wall outlet, which is useful for lessons, rehearsals, and outdoor practice.
Useful connectivity: AUX IN, headphones, stereo outputs, and an external footswitch connection cover many basic practice and performance setups.
User patch storage: Thirty user patches make it possible to organize sounds for different songs or instruments.
Compact construction: Its relatively small footprint is practical for limited pedalboard space.

Limitations

Older interface: The two-character display is functional but less informative than the larger displays found on many newer multi-effects processors.
No modern USB workflow: It is not intended to replace a current USB recording interface or computer-based effects system.
Limited expansion: The effects, routing, and editing options are more focused than those of advanced contemporary floor processors.
Separate adapter requirement: AC operation requires a compatible optional adapter rather than an included mains supply.
Best for straightforward rigs: Players needing extensive amp modeling, deep signal chains, wireless control, or app editing may need a newer product.

The Boss ME-20B Bass Multiple Effects is a strong choice for bassists who value simple controls, portable operation, and dependable core effects. It may be less suitable for musicians building a complex modern digital rig with computer integration and extensive routing.

PDF

Faqs

How do I set up the boss ME-20B Bass Multiple Effects for the first time?

Turn the ME-20B off, then connect your bass to the INPUT jack with a standard instrument cable. Connect OUTPUT L/MONO to your bass amplifier; use OUTPUT R only for a stereo setup. Insert six AA batteries or connect a compatible PSA-series 9V adapter. Select a patch, set your amplifier volume low, and raise the level gradually. Unplug the cable from INPUT after playing because that jack activates battery-powered operation.

What should I do if the boss ME-20B Bass Multiple Effects has no sound?

Check that the bass cable is fully inserted into INPUT and that OUTPUT L/MONO is connected to the amplifier’s input. Confirm the amplifier is on, its volume is raised, and the ME-20B output level is not turned down. Try another cable and test the bass directly through the amplifier. If using batteries, replace all six AA cells together. For an adapter, use the specified PSA-series model and verify the plug is firmly connected.

Can I use headphones with the boss ME-20B Bass Multiple Effects?

Yes, the ME-20B includes a PHONES jack for private monitoring. Connect suitable headphones to this output after setting the level low, then increase it carefully to a comfortable volume. When using headphones, you can practice without sending the signal to an amplifier. If your headphones use a smaller plug, use an appropriate stereo adapter. Avoid connecting headphones to the instrument INPUT or ordinary output jacks.

How can I connect an MP3 player or phone to the boss ME-20B Bass Multiple Effects?

Connect the device’s headphone or line output to the ME-20B AUX IN jack using a suitable stereo miniature cable. Keep the playback device’s volume moderate and adjust the ME-20B and amplifier levels separately to prevent distortion. AUX IN is useful for practicing with backing tracks while monitoring through an amplifier or headphones. Do not connect the phone to INPUT, because INPUT is designed for a bass guitar signal.

How do I save and organize sounds on the boss ME-20B Bass Multiple Effects?

Build a sound by adjusting the effect sections, including compression, distortion, modulation, delay, and the expression pedal assignment. Before saving, compare the patch at the volume used during rehearsal, because tones can seem different at performance level. Store frequently used sounds in an order that matches your set list. Keep a written note or photo of important settings so you can recreate a patch after experimentation.

Why does the boss ME-20B Bass Multiple Effects sound distorted or noisy?

Begin by lowering the bass volume, ME-20B output, and amplifier gain, then raise them one at a time. Excessive effect gain or compression can emphasize noise and cause clipping. Test the bass with effects bypassed to identify whether the problem comes from the instrument, cable, patch, or amplifier. Keep audio cables away from power supplies and replace damaged cables. A fresh, matched set of six AA batteries can also resolve unstable operation.

Can I use an external footswitch with the boss ME-20B Bass Multiple Effects?

The ME-20B provides a FOOT SW jack for compatible external control. Supported options include the BOSS FS-5U single footswitch and FS-6 or FS-7 dual footswitches; the correct connection cable may be required for dual-switch operation. Turn equipment levels down before connecting accessories, and follow the owner’s manual for polarity and function settings. Do not assume every generic footswitch will operate correctly.

How should I maintain and store the boss ME-20B Bass Multiple Effects?

Keep the unit dry, away from extreme heat, dust, and direct sunlight. Disconnect all cables after use, especially the cable in INPUT, which can continue draining the batteries. Remove the six AA batteries if the ME-20B will be stored for an extended period to reduce the risk of leakage. Clean the enclosure with a soft, dry cloth and avoid sprays entering the jacks, switches, or pedal mechanisms.