Crown CDi 4000 Operation Manual page 6

2 Setup
(continued)
2.7 Connect to AC Mains
Connect your amplifier to the AC mains power source (power
outlet) with the supplied AC power cordset. First, connect the IEC
end of the cordset to the IEC connector on the amplifier; then, plug
the other end of the cordset to the AC mains.
WARNINg: The third prong of this connector (ground) is
an important safety feature. Do not attempt to disable
this ground connection by using an adapter or other
methods.
Amplifiers don't create energy. The AC mains voltage and current
must be sufficient to deliver the power you expect. You must
operate your amplifier from an AC mains power source with not
more than a 10% variation above or a 15% variation below the
amplifier's specified line voltage and within the specfied frequency
require ments (indicated on the amplifier's back panel label). If you
are unsure of the output voltage of your AC mains, please consult
your electrician.
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CDi Series Power Amplifiers
2.8 Protecting Your Speakers
It's wise to avoid clipping the amplifier signal. Not only does
clipping sound bad, it can damage high-frequency drivers. The
built-in clip limiter prevents clipping.
Also, avoid sending strong subsonic signals to the amplifier.
High-level, low-frequency signals from breath pops or dropped
microphones can blow out drivers. To prevent subsonic signals,
use the amplifier's DSP to insert a highpass filter (see Section
4.1.6). Alternatively, switch in highpass filters at your mixer. Set the
2.9 Startup Procedure
filter to as high a frequency as possible that does not affect your
Use the following procedure when first turning on your amplifier:
program. For example, try 35 Hz for music and 75 Hz for speech.
On each mixer input channel, set the filter fre quency just below the
1. Turn down the level of your audio source.
lowest fundamental frequency of that channel's instrument.
2. Turn down the level controls of the amplifier.
3. Turn on the "Power" switch. The Power indica tor should glow.
4. Turn up the level of your audio source to an optimum level.
5. Turn up the Level controls on the amplifier until the desired
loudness or power level is achieved. NOTE: In Bridge-Mono
mode, only the Channel 1 Level control is functional (except
for CH1 + CH2 Input Y mode).
6. Turn down the level of your audio source to its normal range.
If you ever need to make any wiring or installation changes, don't
forget to disconnect the power cord.
For help with determining your system's optimum gain structure
(signal levels) please refer to the Crown Amplifier Application
Guide, available online at www.crownaudio.com.
CDi Series Power Amplifiers
3 Operation
3.1 Precautions
Your amplifier is protected from internal and external faults, but you
should still take the following precau tions for optimum performance
and safety:
1. Before use, your amplifier first must be config ured for proper
operation, including input and output wiring hookup. Improper wiring
can result in serious operating difficulties. For information on wiring
and configuration, please consult the Setup section of this manual or,
for advanced setup techniques, con sult Crown' s Amplifier Application
Guide available online at www.crownaudio.com.
3.2 Front Panel Controls and Indicator
A. grille
B, D, E. Sel/Prev/Next Buttons
Three buttons near the LCD screen are used to access menu items.
C. LCD Screen
Backlit liquid crystal display shows speaker presets.
F. Level
Detented rotary level control, one per channel.
Operation Manual Operation Manual
2. Use care when making connections, selecting signal sources and
controlling the output level. The load you save may be your own!
3. Do not short the ground lead of an output cable to the input signal
ground. This may form a ground loop and cause oscillations.
4. WARNINg: Never connect the output to a power supply,
battery or power main. Elec trical shock may result.
5. Tampering with the circuitry, or making unautho rized circuit
changes may be hazardous and invali dates all agency listings.
6. Do not operate the amplifier with the red Clip LEDs constantly
flashing.
2000
H. Power Indicator
Blue LED illuminates when the amplifier has been turned on and has
power.
I. Power Switch
On/off switch applies AC power to the amplifier.
g. Meter group (one per channel)
Thermal Indicator: Red LED illuminates under excessive temperature
conditions.
Clip Indicator: Red LED turns on at the threshold of audible distortion.
7. Do not overdrive the mixer, which will cause clipped signal to be
sent to the amplifier. Such sig nals will be reproduced with extreme
accuracy, and loudspeaker damage may result.
8. Do not operate the amplifier with less than the rated load
impedance. Due to the amplifier' s output protection, such a
configuration may result in pre mature clipping and speaker damage.
Remember: Crown is not liable for damage that results from
overdriving other system components.
9. Crown CDi amplifiers can directly drive 70V/high-Z loads. To
configure your amplifier for this mode of operation, see Section 4.1.6.
–10 Indicator: Green LED flashes when output signal exceeds –10 dB
below clip.
–20 Indicator: Green LED flashes when output signal level exceeds
–20 dB below clip.
Signal Indicator: Green LED flashes when a very low-level signal is
present at input. May be used for troubleshooting cable runs.
Ready Indicator: Green LED illuminates when the amplifier is ready to
produce audio.
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