Roland A-90 v2 Owner's Manual

Owners Manual Bedienungsanleitung Guide dutilisation

Manuale dell'utente Manual del usuario

Manual do proprietrio Gebruikershandleiding

202

Copyright 2007 ROLAND CORPORATION

All rights reserved. No part of this publication may be reproduced in any form without

the written permission of ROLAND CORPORATION.

Thank you, and congratulations on your choice of the Roland AC-90 Acoustic Chorus. 201b

These sections provide important information concerning the proper operation of the unit. Additionally, in order to feel assured that you have gained a good grasp of every feature provided by your new unit, Owners manual should be read in its entirety. The manual should be saved and kept on hand as a convenient reference.

Before using this unit, carefully read the sections entitled:

IMPORTANT SAFETY INSTRUCTIONS (page 2)

USING THE UNIT SAFELY (page 34)

IMPORTANT NOTES (page 5)

AC-90_egfispd.book Page 1 Tuesday, August 14, 2007 10:09 AM

2

CAUTION RISK OF ELECTRIC SHOCK

DO NOT OPEN

ATTENTION: RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK,

DO NOT REMOVE COVER (OR BACK).

NO USER-SERVICEABLE PARTS INSIDE.

REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated dangerous voltage within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons.

The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product.

INSTRUCTIONS PERTAINING TO A RISK OF FIRE, ELECTRIC SHOCK, OR INJURY TO PERSONS.

IMPORTANT SAFETY INSTRUCTIONS SAVE THESE INSTRUCTIONS

WARNING - When using electric products, basic precautions should always be followed, including the following:

1. Read these instructions. 2. Keep these instructions. 3. Heed all warnings. 4. Follow all instructions. 5. Do not use this apparatus near water. 6. Clean only with a dry cloth. 7. Do not block any of the ventilation openings. Install in

accordance with the manufacturers instructions. 8. Do not install near any heat sources such as radiators,

heat registers, stoves, or other apparatus (including amplifiers) that produce heat.

9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A grounding type plug has two blades and a third grounding prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet.

WARNING: IMPORTANT:

As the colours of the wires in the mains lead of this apparatus may not correspond with the coloured markings identifying the terminals in your plug, proceed as follows:

The wire which is coloured GREEN-AND-YELLOW must be connected to the terminal in the plug which is marked by the letter E or by the safety earth symbol or coloured GREEN or GREEN-AND-YELLOW.

The wire which is coloured BLUE must be connected to the terminal which is marked with the letter N or coloured BLACK. The wire which is coloured BROWN must be connected to the terminal which is marked with the letter L or coloured RED.

THIS APPARATUS MUST BE EARTHED THE WIRES IN THIS MAINS LEAD ARE COLOURED IN ACCORDANCE WITH THE FOLLOWING CODE. GREEN-AND-YELLOW: EARTH, BLUE: NEUTRAL, BROWN: LIVE

For the U.K.

10. Protect the power cord from being walked on or pinched particularly at plugs, convenience receptacles, and the point where they exit from the apparatus.

11. Only use attachments/accessories specified by the manufacturer.

12. Unplug this apparatus during lightning storms or when unused for long periods of time.

13. 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.

WARNING: To reduce the risk of fire or electric shock, do not expose this apparatus to rain or moisture.

AC-90e_01.fm 2

AC-90_egfispd.book Page 3 Tuesday, August 14, 2007 10:09 AM

USING THE UNIT SAFELY

001

Before using this unit, make sure to read the instructions below, and the Owners Manual.

.......................................................................................................... 002a

Do not open or perform any internal modifica- tions on the unit.

.......................................................................................................... 003

Do not attempt to repair the unit, or replace parts within it (except when this manual provides specific instructions directing you to do so). Refer all servicing to your retailer, the nearest Roland Service Center, or an authorized Roland distributor, as listed on the Information page.

.......................................................................................................... 004

Never use or store the unit in places that are:

Subject to temperature extremes (e.g., direct sunlight in an enclosed vehicle, near a heating duct, on top of heat-generating equipment); or are

Damp (e.g., baths, washrooms, on wet floors); or are

Humid; or are

Exposed to rain; or are

Dusty; or are

Subject to high levels of vibration.

.......................................................................................................... 008a

The unit should be connected to a power supply only of the type described in the operating instructions, or as marked on the rear side of unit.

.......................................................................................................... 009

Do not excessively twist or bend the power cord, nor place heavy objects on it. Doing so can damage the cord, producing severed elements and short circuits. Damaged cords are fire and shock hazards!

..........................................................................................................

010

This unit, either alone or in combination with an amplifier and headphones or speakers, may be capable of producing sound levels that could cause permanent hearing loss. Do not operate for a long period of time at a high volume level, or at a level that is uncomfortable. If you experience any hearing loss or ringing in the ears, you should immediately stop using the unit, and consult an audiologist.

........................................................................................................... 011

Do not allow any objects (e.g., flammable material, coins, pins); or liquids of any kind (water, soft drinks, etc.) to penetrate the unit.

........................................................................................................... 012a

Immediately turn the power off, remove the power cord from the outlet, and request servicing by your retailer, the nearest Roland Service Center, or an authorized Roland distributor, as listed on the Information page when:

The power-supply cord or the plug has been damaged; or

If smoke or unusual odor occurs

Objects have fallen into, or liquid has been spilled onto the unit; or

The unit has been exposed to rain (or otherwise has become wet); or

The unit does not appear to operate normally or exhibits a marked change in performance.

........................................................................................................... 013

In households with small children, an adult should provide supervision until the child is capable of following all the rules essential for the safe operation of the unit.

........................................................................................................... 014

Protect the unit from strong impact. (Do not drop it!)

...........................................................................................................

Used for instructions intended to alert the user to the risk of injury or material damage should the unit be used improperly.

* Material damage refers to damage or other adverse effects caused with respect to the home and all its furnishings, as well to domestic animals or pets.

Used for instructions intended to alert the user to the risk of death or severe injury should the unit be used improperly.

The symbol alerts the user to things that must be carried out. The specific thing that must be done is indicated by the design contained within the circle. In the case of the symbol at left, it means that the power- cord plug must be unplugged from the outlet.

The symbol alerts the user to important instructions or warnings.The specific meaning of the symbol is determined by the design contained within the triangle. In the case of the symbol at left, it is used for general cautions, warnings, or alerts to danger.

The symbol alerts the user to items that must never be carried out (are forbidden). The specific thing that must not be done is indicated by the design contained within the circle. In the case of the symbol at left, it means that the unit must never be disassembled.

3

AC-90e_01.fm 4

015

Do not force the units power-supply cord to share an outlet with an unreasonable number of other devices. Be especially careful when using extension cordsthe total power used by all devices you have connected to the extension cords outlet must never exceed the power rating (watts/amperes) for the extension cord. Excessive loads can cause the insulation on the cord to heat up and eventually melt through.

.......................................................................................................... 016

Before using the unit in a foreign country, consult with your retailer, the nearest Roland Service Center, or an authorized Roland distributor, as listed on the Information page.

.......................................................................................................... 026

Do not put anything that contains water (e.g., flower vases) on this unit. Also, avoid the use of insecticides, perfumes, alcohol, nail polish, spray cans, etc., near the unit. Swiftly wipe away any liquid that spills on the unit using a dry, soft cloth.

..........................................................................................................

101a

The unit should be located so that its location or position does not interfere with its proper venti- lation.

........................................................................................................... 102a

Always grasp only the plug on the power-supply cord when plugging into, or unplugging from an outlet.

........................................................................................................... 103a

At regular intervals, you should unplug the power plug and clean it by using a dry cloth to wipe all dust and other accumulations away from its prongs. Also, disconnect the power plug from the power outlet whenever the unit is to remain unused for an extended period of time. Any accumulation of dust between the power plug and the power outlet can result in poor insulation and lead to fire.

........................................................................................................... 104

Try to prevent cords and cables from becoming entangled. Also, all cords and cables should be placed so they are out of the reach of children.

........................................................................................................... 106

Never climb on top of, nor place heavy objects on the unit.

........................................................................................................... 107a

Never handle the power cord or its plug with wet hands when plugging into, or unplugging from, an outlet.

........................................................................................................... 108a

Before moving the unit, disconnect the power plug from the outlet, and pull out all cords from external devices.

........................................................................................................... 109a

Before cleaning the unit, turn off the power and unplug the power cord from the outlet.

........................................................................................................... 110a

Whenever you suspect the possibility of lightning in your area, pull the plug on the power cord out of the outlet.

........................................................................................................... 120

Always turn the phantom power off when connecting any device other than condenser microphones that require phantom power. You risk causing damage if you mistakenly supply phantom power to dynamic microphones, audio playback devices, or other devices that dont require such power. Be sure to check the specifica- tions of any microphone you intend to use by referring to the manual that came with it.

(This instruments phantom power: 48 V DC, 10 mA Max) ........................................................................................................... Connect mains plug of this model to a mains

socket outlet with a protective earthing connection.

...........................................................................................................

4

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IMPORTANT NOTES

291b

In addition to the items listed under IMPORTANT SAFETY INSTRUCTIONS and USING THE UNIT SAFELY on pages 2 and 4, please read and observe the following:

Power Supply 301

Do not connect this unit to same electrical outlet that is being used by an electrical appliance that is controlled by an inverter (such as a refrigerator, washing machine, microwave oven, or air conditioner), or that contains a motor. Depending on the way in which the electrical appliance is used, power supply noise may cause this unit to malfunction or may produce audible noise. If it is not practical to use a separate electrical outlet, connect a power supply noise filter between this unit and the electrical outlet.

307

Before connecting this unit to other devices, turn off the power to all units. This will help prevent malfunctions and/or damage to speakers or other devices.

308

Although the LEDs are switched off when the POWER switch is switched off, this does not mean that the unit has been completely disconnected from the source of power. If you need to turn off the power completely, first turn off the POWER switch, then unplug the power cord from the power outlet. For this reason, the outlet into which you choose to connect the power cords plug should be one that is within easy reach and readily accessible.

Placement 351

Using the unit near power amplifiers (or other equipment containing large power transformers) may induce hum. To alleviate the problem, change the orientation of this unit; or move it farther away from the source of interference.

352a

This device may interfere with radio and television reception. Do not use this device in the vicinity of such receivers.

352b

Noise may be produced if wireless communications devices, such as cell phones, are operated in the vicinity of this unit. Such noise could occur when receiving or initiating a call, or while conversing. Should you experience such problems, you should relocate such wireless devices so they are at a greater distance from this unit, or switch them off.

354b

Do not expose the unit to direct sunlight, place it near devices that radiate heat, leave it inside an enclosed vehicle, or otherwise subject it to temperature extremes. Also, do not allow lighting devices that normally are used while their light source is very close to the unit (such as a piano light), or powerful spotlights to shine upon the same area of the unit for extended periods of time. Excessive heat can deform or discolor the unit.

355b

When moved from one location to another where the temperature and/or humidity is very different, water droplets (condensation) may form inside the unit. Damage or malfunction may result if you attempt to use the unit in this condition. Therefore, before using the unit, you must allow it to stand for several hours, until the condensation has completely evaporated.

356

Do not allow rubber, vinyl, or similar materials to remain on the unit for long periods of time. Such objects can discolor or otherwise harmfully affect the finish.

359

Do not paste stickers, decals, or the like to this instrument. Peeling such matter off the instrument may damage the exterior finish.

360

Depending on the material and temperature of the surface on which you place the unit, its rubber feet may discolor or mar the surface. You can place a piece of felt or cloth under the rubber feet to prevent this from happening. If you do so, please make sure that the unit will not slip or move accidentally.

Add

Do not allow objects to remain on top of the unit while it is in operation.

Do not sit or lean on top of the unit.

Maintenance 401a

For everyday cleaning wipe the unit with a soft, dry cloth or one that has been slightly dampened with water. To remove stubborn dirt, use a cloth impregnated with a mild, non-abrasive detergent. Afterwards, be sure to wipe the unit thoroughly with a soft, dry cloth.

402

Never use benzine, thinners, alcohol or solvents of any kind, to avoid the possibility of discoloration and/or deformation.

Additional Precautions 553

Use a reasonable amount of care when using the units buttons, sliders, or other controls; and when using its jacks and connectors. Rough handling can lead to malfunctions.

556

When connecting / disconnecting all cables, grasp the connector itselfnever pull on the cable. This way you will avoid causing shorts, or damage to the cables internal elements.

557

A small amount of heat will radiate from the unit during normal operation.

558a

To avoid disturbing your neighbors, try to keep the units volume at reasonable levels. You may prefer to use headphones, so you do not need to be concerned about those around you (especially when it is late at night).

559a

When you need to transport the unit, package it in the box (including padding) that it came in, if possible. Otherwise, you will need to use equivalent packaging materials.

562

Some connection cables contain resistors. Do not use cables that incorporate resistors for connecting to this unit. The use of such cables can cause the sound level to be extremely low, or impos- sible to hear. For information on cable specifications, contact the manufacturer of the cable.

921

To prevent malfunction and/or damage to speakers or other devices, always turn down the volume, and turn off the power on all devices before making any connections.

922

This instrument is equipped with balanced XLR/TRS type jacks. Wiring diagrams for these jacks are shown below. Make connec- tions after first checking the wiring diagrams of other equipment you intend to connect.

fig.XLR/TRSJack.eps

941

Once the connections have been completed (p. 11), turn on power to your various devices in the order specified. By turning on devices in the wrong order, you risk causing malfunction and/or damage to speakers and other devices. When powering up:

Turn on the power to the AC-90 last. When powering down:

Turn off the power to the AC-90 first. Add

Wrap the AC cord around the cord hook when trans-porting or storing the unit.

5

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Contents

USING THE UNIT SAFELY ............................................3

IMPORTANT NOTES ......................................................5

Contents..............................................................................6

English Main Features .........................................................7

Names of Things and What They Do .................8 Control Panel...............................................8 Rear Panel ..................................................12

Example of Using Two Channels Combined...... 14

How to Use the Folding Stand...........................15

Using a Speaker Stand ........................................16

Deutsch Hauptmerkmale ...................................................17

Bezeichnungen und Funktionen der Bedienelemente ....................................................18

Bedienfeld..................................................18 Rckseite....................................................22

Beispiel fr die kombinierte Verwendung zweier Kanle .......................................................24

Verwendung des ausklappbaren Bgels..........25

Verwenden eines Lautsprecherstativs..............26

Franais Caractristiques principales ...............................27

Noms et fonctions des lments ........................28 Panneau de commande ...........................28 Panneau arrire.........................................32

Exemple dutilisation de deux canaux ensemble ..................................................34

Utilisation du support escamotable ..................35

Utilisation dun pied pour haut-parleur ..........36

Italiano Caratteristiche principali ....................................37

Denominazione e utilizzo delle funzioni .........38 Pannello di controllo ................................38 Pannello posteriore ..................................42

Esempio di utilizzo di due canali combinati ....... 44

Modalit di utilizzo del supporto pieghevole.............................................................45

Utilizzo di un supporto casse.............................46

Espaol Principales caractersticas ...................................47

Nombres de componentes y sus funciones......48 Panel de control ........................................48 Panel trasero ..............................................52

Ejemplo de uso de dos canales combinados......54

Cmo utilizar el soporte plegable .....................55

Utilizacin de un soporte de altavoz ................56

Portugus Principais caractersticas .....................................57

Nomes das partes e suas funes ......................58 Painel de controle .....................................58 Painel traseiro............................................62

Exemplo de uso de dois canais combinados...........................................................64

Como utilizar o suporte dobrvel .....................65

Utilizando um suporte para alto-falante ..........66

Nederlands Belangrijkste kenmerken.....................................67

Namen van onderdelen en hun functies ..........68 Voorpaneel ................................................68 Achterpaneel .............................................72

Voorbeeld van gecombineerd gebruik van twee kanalen .................................................74

De vouwstandaard gebruiken ...........................75

Een luidsprekerstandaard gebruiken ...............76

Block Diagram .................................................................77

How to Use the Carrying Case......................................77

Specifications ...................................................................78

AC-90_egfispd.book Page 7 Tuesday, August 14, 2007 10:09 AM

Main Features

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The AC-90 is a high-performance monitor amp developed exclusively for use with acoustic instruments. It is capable of faithfully expressing all the harmonic richness of an acoustic instruments sound.

Compact, High-Performance Stereo Amp

The finely tuned design of the cabinet is meant to enhance the sound of acoustic instruments. Within this cabinet, there are two 8 inch woofers, two tweeters, and a 45 W + 45 W stereo ampall of which were newly designed just for the AC-90. As a result, the unit is capable of delivering a more natural, acoustic instrument sound across a broad range of frequencies.

Thanks to a power amp that was designed to be as light as possible, and the use of new materials for the woofers, an overall reduction in the weight of the unit has been achieved.

Features Two Independent Channels, GUITAR and MIC/LINE

Each channel includes a 3-band equalizer. GUITAR channel handles both piezo and magnetic

pickups. The MIC/LINE channel offers phantom power,

produced by highly reliable, dedicated 48 V output phantom circuitry.

Using the MIC/LINE channel for LINE input allows you to connect guitars with magnetic pickups. You can also use a piezo pickup (GUITAR channel) and a magnetic pickup (MIC/LINE channel) at the same time, and mix (blend) the sounds together.

High-Quality Digital Effects Three kinds of stereo chorus effects are provided. There

is the spatially synthesized SPACE chorus, the RICH chorus (which is divided into frequency bands), and the WIDE chorus (which is also divided into frequency bands while offering even greater expansiveness).

Includes stereo reverb developed especially for acoustic instruments. This allows you to add a sense of spaciousness and natural body to the sound.

Equipped with delay effects that can produce sound with a tonal quality that is soft and tuned specifically for acoustic instruments.

An optional foot switch can also be used to turn the effects on and off.

Anti-Feedback Suppresses Feedback Anti-feedback features two ways to detect the feedback

point. You can use the Manual settings, or you can use the Auto settings, which provide for the automatic detection of the feedback point.

You can connect an optional foot switch and use your foot to operate this feature.

Mute Function The provided Mute switch makes it easy for you to mute

the sounds for the AC-90s own speakers as well as the sounds from LINE OUT. By using the Mute function, you can plug in and out noiselessly at the guitar. Furthermore, when you have a tuner connected to TUNER OUT, the Mute function lets you tune your instrument without outputting any sound.

You can connect an optional foot switch and use your foot to turn this on and off.

External Input Jacks (AUX IN) Includes external input jacks, allowing you to connect a

CD player, backing machine, or other device in stereo. These include both RCA phono jacks and 1/4 phone

jacks, making it possible to connect just about any kind of device.

Multiple Output Connectors Features DI Out, which allow you to directly output the

signals input from connected instruments and mics. You can also connect a tuner. TRS balanced output is supported.

Line outs feature 1/4 phone mono-output jacks in addition to XLR connectors for stereo output. You can use a single AC-90 for all applications.

It also features a Subwoofer Out. Connecting a powered subwoofer allows you to play with an even punchier, more powerful low end.

The amp also provides a headphones jack, which you can use when playing during nighttime hours and when making sound checks.

Convenient Placement Features Equipped with a folding stand, which allows you to

change the angle of the amp when using it for monitoring purposes.

Includes a speaker stand adapter, which allows you to attach the AC-90 to a speaker stand. This makes using the AC-90 easier when you are performing standing up, and allows you to use the amp as a simple PA.

Also included is a carrying case for greater portability.

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Names of Things and What They Do

Control Panel fig.010

1. INPUT

(GUITAR CHANNEL)

Connect guitars here.

(MIC/LINE CHANNEL)

Connect mics and line-level devices here. You can also connect guitars with pickups equipped with preamps.

This handles balanced input, so you can connect 1/4 phone TRS jacks and XLR-type connectors. fig.030

You can use the two channels in combination. Refer to Example of Using Two Channels Combined (p. 14). 983

* Feedback could be produced depending on the location of

microphones relative to speakers. This can be remedied by:

Changing the orientation of the microphone(s). Relocating microphone(s) at a greater distance from speakers. Lowering volume levels.

2. PICKUP Button This switches the input circuitry for either piezo or magnetic pickups, according to the type of pickup on the connected guitar. Press down the button for magnetic pickups.

* Set this to MAGNETIC if your guitar has an active pickup

equipped with a preamp.

3. SHAPE Button Setting this to ON modifies the midrange to create a bright tone suitable for strumming chords.

This emphasizes brushing sounds, allowing you to strum with a more edgy feeling.

4. PHANTOM Switch This turns the phantom power on and off.

Set this to ON when connecting mics that require phantom power (condenser mic, etc.).

Set this to OFF when connecting mics that do not require phantom power or other devices.

Use the following sequence when connecting mics that require phantom power:

1.Turn the PHANTOM switch off.

2.Connect the mic.

3.Turn the PHANTOM switch on.

Supplying phantom power to mics that do not require it or supplying it to other devices may cause such equipment to malfunction. Always be sure to turn the switch off before connecting.

* To protect the circuitry, all output is muted momentarily after

the PHANTOM switch is turned on or off.

* Phantom power is supplied only to the XLR connectors for the

MIC/LINE channel INPUT.

* Noise may be produced if connectors are connected or

disconnected while the phantom power is turned on.

1 2 3 10 11 16 1796 7 8

4 5 12 13 14 15 18

XLRTRS

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Names of Things and What They Do

AC-90_egfispd.book Page 9 Tuesday, August 14, 2007 10:09 AM

Phantom Power

Because they have a comparatively wider range and better sound quality than dynamic mics, condenser mics are often used for miking acoustic guitars. However, they require a power source to operate. Although some condenser mics run off batteries placed within the mic housing, in many cases a type of power supply known as phantom power is required. This power supply uses the existing mic cable to feed power.

The AC-90s phantom power is output at a constant 48 V, so it conforms to professional specifications required at recording studios.

5. SELECT Button This switches the input level to match that of the connected device (mic or line).

You can connect guitars with magnetic pickups when LINE is selected with the SELECT button.

* Note that the volume is increased if the switch is set to MIC

when you have a line-level device connected.

6. VOLUME Knobs

(GUITAR CHANNEL)

Adjusts the volume of the GUITAR channel.

* To accommodate the lower output of piezo pickups, the volume

level when the VOLUME knob is between the 7 and 10

positions is set somewhat higher when the PICKUP button is

set to PIEZO in comparison with the MAGNETIC setting.

(MIC/LINE CHANNEL)

Adjusts the volume of the MIC/LINE channel.

* When using the AC-90 with the GUITAR channel and MIC/

LINE channel mixed, adjust the volume balance between the

two channels with the VOLUME knob.

7. BASS Knobs Adjust the level of the low-frequency range.

8. MIDDLE Knobs Adjust the level of the midrange.

9. TREBLE Knobs Adjust the level of the high-frequency range.

The tone of an acoustic instrument can vary immensely from one instrument to the next. The kind of sound required also varies according to how an instrument is being used in a particular ensemble. Actively use the BASS, MIDDLE, and TREBLE knobs to adjust the tone to suit the instrument you are using and the conditions in which it is being used.

(Example)

When using the AC-90 with the speaker stand attached, you may want to turn up the BASS knob so the lower range is perceived better.

If the sound seems too harsh, such as immediately after changing strings, you may want to turn down the TREBLE knob to cut back on the high frequencies.

10. CHORUS Buttons Switch chorus on and off.

When on, the indicator is lit.

You can use a foot switch (the optional BOSS FS-5U) to switch chorus on and off. Turning chorus on and off with the foot switch works on both channels.

11. CHORUS Knob Turn this knob to select among the three types of chorus (SPACE, RICH, and WIDE).

You can adjust the amount of effect applied by changing the position of the knob.

* This is enabled when the CHORUS button is in the ON

position.

* The markings indicating the SPACE and RICH positions are

approximate. Listen to the sound to confirm the effect as you

make adjustments.

SPACE

This is a spacially synthesized chorus. With spacially synthesized chorus, a method available only in stereo, the chorus effect is created by taking the sound from the right speaker (from which the effect sound is output), and the sound from the left speaker (which outputs the direct sound), and then mixing them in the actual space. This creates a greater lateral spread than that produced when the sounds are mixed electronically, providing a more natural sense of breadth.

9

Names of Things and What They Do

AC-90_egfispd.book Page 10 Tuesday, August 14, 2007 10:09 AM

RICH

This is a stereo chorus that is divided into three frequency ranges.

Here, the effect is separated into three bands, low-frequency, midrange, and high-frequency, and by applying the most suitable amount of chorus effect in each range, it provides a sense of fullness and breadth that is perfectly suited to the acoustic guitar.

The low end is firmly in the center, and sound spreads out more and more as the sound rises from the midrange up through the higher frequencies.

WIDE

While also relying on the division of sound into separate bands, this chorus offers even greater expansiveness than RICH.

The sound image spreads beyond the AC-90s speakers, producing an effect that seems to envelope the listener in sound.

12. REVERB/DELAY Knob You can adjust this knob to switch between the reverb and delay effects.

You can adjust the amount of effect applied by changing the position of the knob.

* Turn the knob to OFF if you are not using the reverb or

delay effect.

* The markings indicating the reverb and delay positions are

approximate. Listen to the sound to confirm the effect as you

make adjustments.

REVERB

This stereo reverb, developed especially for acoustic instruments, gives a sense of spaciousness and natural sonic quality.

Turn the knob to adjust the volume of the reverb effect.

DELAY

This delay, developed especially for acoustic instruments, adds soft reflections to the original sound.

Turn the knob to change the delay time.

* You can use a foot switch (the optional BOSS FS-5U) to

switch the reverb and delay on and off.

13. FREQUENCY Knob This selects the frequency at which the anti-feedback function operates.

Also, the position of the knob determines whether Auto or Manual settings are selected.

fig.031

* Turn the knob to OFF if you are not using anti-feedback.

14. START Button This is used for Auto settings (p. 11). Pressing the button performs automatic detection of feedback-whine frequencies.

The indicators show the operating status of the automatic detection function.

Standby: Flashes slowly

During Detection: Flashes rapidly

After Detection: Remains lit

* Holding down the START button for one second or longer

returns the unit to standby for automatic detection.

How to Use ANTI-FEEDBACK fig.32

Anti-feedback is a function that controls feedback that arises between the guitar or mic and the amp.

The feedback is suppressed by attenuating the frequency at which the feedback occurs.

* This is not designed to work with respect to the high-frequency

feedback that can occur when using microphones.

Anti-feedback can be used in two different ways; you can make use of either the Auto settings or the Manual settings.

* Use either when feedback whine occurs.

Feedback

This is a phenomenon whereby signals output from the speakers are picked up again by the mic or pickup, and the sound is further amplified and output from the speakers, resulting in an unpleasant oscillating sound.

* If the anti-feedback alone does not control the feedback, adjust your settings, for example by lowering the volume or cutting the low frequencies.

* To prevent feedback during a performance, we recommend making the anti-feedback setting before the performance.

MANUAL

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Names of Things and What They Do

AC-90_egfispd.book Page 11 Tuesday, August 14, 2007 10:09 AM

Setting the Feedback Point Automatically

This automatically detects the frequency at which feedback occurs and suppresses feedback.

* Use in conditions where feedback occurs.

1. Cause feedback whine to occur.

2. Turn the FREQUENCY knob to the AUTO position. fig.033

The ANTI-FEEDBACK indicator flashes slowly, and automatic detection goes into standby.

3. Press the START button.

Automatic detection of the feedback point starts. The indicator flashes rapidly when detection is in progress, and when the feedback point is found, the indicator lights steadily. If no feedback point is detected, the indicator flashes slowly, and the automatic detection function returns to standby.

4. Press the START button once more to conduct the

automatic detection again.

Setting the Feedback Point Manually

1. Cause feedback whine to occur.

2. Turn the knob, moving through the range of L through

H (the ANTI-FEEDBACK indicator lights up) to search

for the frequency at which the feedback is to be

suppressed. fig.34

Turning the knob clockwise suppresses progressively more treble feedback, and turning it counterclockwise suppresses progressively more bass feedback.

You can use a foot switch (the optional BOSS FS-5U, FS-6) to run automatic detection of the feedback frequency or to turn the anti-feedback function on and off.

You can use anti-feedback even when feedback is not a problem. For example, you can use it to remove undesirable resonance in the low to midrange, as well as correct other problems with the sound quality.

15. MUTE Button This switches the Mute function on and off.

When you press the button, the MUTE indicator flashes, muting is turned on, and the speaker output and sounds from SUB WOOFER OUT and LINE OUT are muted.

With the mute function activated, you do not need to turn down the VOLUME knob or MASTER knob to mute the noise when plugging into, or unplugging from your guitar.

* Sounds from the DI OUT/TUNER OUT and PHONES jacks

are not muted.

By connecting a tuner (optional) to DI OUT/TUNER OUT and then pressing the MUTE button, you can tune your instrument without the sound being output from the speakers.

You can use a foot switch (optional BOSS FS-5U or FS-6) to switch muting on and off. (p. 13)

16. MASTER Knob Adjusts the overall volume level.

* LINE OUT cannot be adjusted.

17. PHONES Jack Headphones are connected here. No sounds are output from the speakers or from SUB WOOFER OUT when headphones are connected.

18. POWER Switch This turns the AC-90s power on and off.

The POWER indicator lights up when the power is on. 945

* If you need to turn off the power completely, first turn off the

POWER switch, then unplug the power cord from the power

outlet. Refer to Power Supply (p. 5) 942

* Due to a circuitry protection feature, this unit requires a few

moments after it has been turned on before it is ready for

normal operation. 943

* Always make sure to have the volume level turned down before

switching on power. Even with the volume all the way down,

you may still hear some sound when the power is switched on,

but this is normal, and does not indicate a malfunction.