Acoustic Image + Models - Manual (Page 6)

back on.
Anytime anything is plugged into the
headphone output jack, the amp will be muted so make sure that nothing is plugged
into the jack when you want to use the amp normally.
The amp head component of the Coda+ and Corus+ can be removed and used as a
stand-alone amplifier. To remove the head unit, first disconnect the speaker “pigtail”
that connects the speaker cabinet to the amp, then unscrew the docking screws on
the rear panel until they are loose. Grip the cabinet as shown and use the tips of your
fingers to push the head unit out. The fit is quite snug so some force will be needed.
Once you have removed the head, you will notice the rubber feet stored in a
compartment on the bottom. Remove the feet and screw them into the four positions
on the bottom of the head. When you want to put the head back into the cabinet, you
will have to remove the feet and put them back into the storage compartment.
To reinsert the head unit, grip the cabinet as shown and push it in with your thumbs.
Again, the fit is snug so some force will be needed. Once the head unit is in place,
tighten the docking screws to pull the head tight to the docking plate. Reconnect the
speaker cable and the unit is ready to go.
An extension speaker (ideally, the Contra EX or Corus EX) can be connected to the
amp to increase its output level using the jack provided on your amp’s rear panel.
Speakers are connected via Neutrik Speakon connectors (“twist lock” type). These
connectors are used because of their low contact resistance and non-shorting
operation. The output of each Speakon connector is wired to pole “1”. Make sure
the cables you use to connect an external speaker are similarly wired.
The Contra has a single speaker output on its rear panel. The Coda+ and Corus+
have two outputs but one of them is used to connect to the internal speakers via the
short pigtail. So, each combo has one output for connecting an extension cabinet.
The power amplifier in all of the combos is capable of driving speaker loads as low as
2 ohms.
Use a high quality speaker system in order to get the maximum
performance from the amp. The Acoustic Image Contra EX or Corus EX are
excellent choices.
There is about a 5 second delay between removal of the plug and the
amp coming back on, so expect a pause before you will hear anything from the
amp after the headphone is removed.
Docking System
Connecting An Extension Speaker
Removal Insertion
8
The power amp is short circuit protected. If a short is connected to the extension
speaker jack (or if the internal speaker is shorted), the output signal will be
interrupted until the short is removed. If a short is present, you will hear a ticking
sound at 3 to 4 second intervals which indicates that the short circuit protection is
working.
A recessed switch on the rear panel of the Contra allows the internal speakers of the
combo to be shut off. This can be useful in two circumstances. The first is when you
are recording from the direct out of the preamp and don’t want the output of the
combo amp to be heard. In that case, switch the internal speakers off and set the
master level to zero. By setting the master level to zero, the signal to the power amp
is turned off and it is not driven without a speaker load which can damage the amp.
The second circumstance is when
you are using an external speaker system and want to turn the internal speakers off
so that only the external speaker is heard. It can also come in handy when playing a
really loud gig with an external speaker and you don’t want to overdrive and possibly
damage the internal speakers. But, keep in mind that when the switch is in the off
position, no sound will be heard from the amp. So,
The omnidirectional low frequency output of the Contra, Coda+, Corus+, Contra EX
and Corus EX makes speaker placement relatively noncritical. You will easily be
heard all over the bandstand no matter where one or more are located. However,
best results are obtained when the cabinet is placed on the floor. Putting the unit on
a shelf or stand will reduce bass frequencies. There may be circumstances where
this is desirable. Again, feel free to experiment to find the sound that is best for you.
In some settings, such as a hollow stage or small, “boomy” room, your amp or
enclosure will produce too much bass. One way to cut unwanted bass output is to
use the built in tilt back feature to lift the front of the cabinet, reducing the coupling to
the floor. To do this, pull the stand into its forward position and set the combo in place
on the floor. The stand is spring loaded so when you pick up the unit, the stand will
spring back into its storage position. You may want to use the tilt stand at all times in
order to aim the high frequency output of the speaker toward your ear so that you
can better hear the amp.
To be on the safe side, you should shut off the power to the amp
before connecting or disconnecting speakers from the unit.
Internal Speaker Defeat Switch (Contra only)
Be sure to set the master level to zero when you have turned off the internal
speakers (or have disconnected the internal speaker in the case of the Coda+
or Corus+) and another speaker load is not connected to the amp. Operating
the combo with no load and the internal speakers disconnected and the
master level turned up can damage the amp.
if you go to use the amp and
there is no sound, check that the internal speaker defeat switch is on before
you panic.
Tilt Mechanism
Speaker Placement (Combos or Extension Cabs)
9