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Contents
Welcome
The Basics 1
Operation 2
Power 2
Preamp 2
Inputs 2
Controls 3
Notch/Low Cut Filter 3
Control Panel Drawings 4
Signal Flow Diagram 4
Effects Loop 6
Direct Out 6
Mute Switch 6
Stereo Operation 7
Effects 7
External Speaker Jack 7
Speaker Placement 8
Tilt Mechanism 8
Tweeter Switch 8
Care 8
Warranty And Repair 8
Specifications 9
The information in this manual is subject to change without notice.
No part of this manual may be reproduced by mechanical,
electronic or other means in any form without prior written
permission from Acoustic Image.
The Acoustic Image logo is a registered trademark of Acoustic
Image LLC. Contra, Coda R and Contra EX are trademarks of
Acoustic Image LLC.
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Welcome to Acoustic Image!
You have purchased a state-of-the-art musical instrument amplifier system,
combining purity, power and portability in a package that sets a new standard
in high fidelity amplification.
Each of our designs is engineered to accurately reproduce the sound of
acoustic and electric instruments, delivering flat frequency response across
the entire musical spectrum; extended, tight, well-controlled bass; and
complete clarity of sound reproduction.
This manual provides operating information for your Acoustic Image Contra,
and Coda R combo amp or Contra EX extension speaker cabinet.
The Basics
Both of our combo amps are based on the same superb class-D 400-watt (4
ohms) power amplifier, on a compact three-way speaker system (also used in
the Contra EX) and on a sophisticated, sensitive preamplifier. The features of
the preamp define the specific combo model.
The power amp is a high efficiency design that requires no external heat sinks
or cooling fans and is capable of driving loads as low as 2 ohms. AC power and
output speaker jacks are located on the rear of the enclosure. A standard,
three-prong detachable AC power cord is used to provide power to the unit,
while AC voltage selection switch allows the unit to operate at 115V/60 Hz or
230V/50 Hz. Japan models operate at 100V, 50/60 Hz only. See the rear panel
of your amp to verify the AC voltage capability.
The Contra combo is equipped with a one-channel preamp, the Coda R adds a
second, identical channel and a six-program effects unit. The input channels
of both preamp types incorporate combo jack interfaces that allow either a high
impedance instrument input (to optimize the sound of piezo-type pickups) or a
mic input, a three-band EQ, an effects loop with return level control, a
selectable notch/low cut filter for feedback control and reduction of low
frequency boominess, a direct out capability with ground lift and pre/post EQ
switch, a master level control and a mute switch. The two-channel preamp of
the Coda R has a switch that allows the second channel to be disconnected
from the main amp and connected to a satellite power amp to create a stereo
system.
All of our speaker enclosures incorporate a 10-inch downfiring woofer, a 5-inch
frontfiring midrange, and a 1-inch defeatable tweeter. A built-in, spring loaded
tilt mechanism allows the cabinet to be tilted back to better direct sound to
your listening position. The cabinet is made of an acoustically inert, high
durability, injection molded polymer material which dramatically reduces the
weight of the cabinet. Each unit comes with a fitted slip cover and shoulder
strap. Both padded and hard shell cases are available as accessories.
While our combos and speakers are designed to play loudly--and clearly-enough so that you can be heard in most gigging situations, they are not suited
to playing at extreme volumes. Generating high SPLs may require an
extension cabinet such as the Contra EX or augmentation by a larger house
system.
1
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Operation
Power
On
Tweeter Switch
CAU TION: TO REDU CE
THE RISK OF FIRE, REPLACE
FUSE WITH THE SAME TYPE
6.3A FA ST BLOW FUS E
CAUTION: TO REDUCE THE
RISK OF ELECTRIC SHOCK,
DO NOT RE MOVE COVER .
NO USER SERVICEABLE PARTS
INSIDE . REFER SERVIC ING
TO QUALIFIED PERSONNE L.
Fuse
I
Power Switch
AC Input
115/230 VAC
50/60 Hz
0
400 Watts
V
5
11
Voltage Switch
115/230V
â8ôÌ£{:â-YN„ 〈J
Combo Rear Panel
Plug the detachable AC power cord into the receptacle on the back of the amp
and into a wall receptacle. A power switch next to the AC connector turns on
power to the pre- and power amps, illuminating a “power on” indicator on the
front panel of the amp. A 6.3-amp fast blow fuse is mounted on the back panel.
To replace the fuse, turn off the amp, remove the AC cord and use a small
screwdriver to remove the fuse from the fuse holder. A spare fuse is included
with this manual.
All combos will work with either 115 volt, 60 Hz AC or 230 volt, 50 Hz AC power.
A switch located on the rear panel selects the appropriate voltage. Note that
the correct AC power cord must be used for connection to the appropriate wall
plug. If you do not have the right cord, you can buy one from an electronics or
computer store. Be sure the switch is in the correct position for the intended
application. Operation at 230 volts with the switch in the 115 volt position
will damage the unit.
Please note that units sold in Japan operate at 100 volts only. The above
mentioned voltage switch is not available for these units. Operation of a 100
volt amp at any other voltage than 100 volts will damage the unit.
Preamp
Refer to the signal flow diagram and the control panel drawings for more
information (page 4).
Inputs
The Contra and Coda R use combo jacks for the input to each channel of their
preamp. Either an XLR or 1/4 inch connector can be plugged into this type of
jack. The 1/4 inch input has a 1 megohm input impedance that is optimized to
get the best sound from piezo pickups. The XLR input is a low impedance
balanced input with sufficient gain to allow microphones to be plugged into it.
Phantom power is available through the connector for powering a mic or
outboard preamp and can be activated using the push button switch located
next to the connector. To avoid an audible “pop”, set the mic input level control
all the way off when switching on the phantom power. An LED indicates when
phantom power is on. The two channels of the Coda R combo can blended to
mix two instruments, 2 microphones or a mic and an instrument thereby
performing much like a small PA system.
2