MA Series Power Amplifiers
3 Setup
3.7 Set Input Sensitivity
The input sensitivity switch inside the amplifier is set to 0.775 volt RMS at the factory. (Factory setting for international models is 1.4V). It can be changed to 1.4 volts or a voltage gain of 26 dB. The 26 dB gain setting is equivalent to a sensitivity of 2.2 volts for the
To change the input sensitivity:
1. Turn off and unplug the amplifier from the AC source.
2. Remove the input module on the back panel.
3. Locate the labeled access hole for the sensitivity switch (Figure 3.9). The sensitivity switch will not be visible because it is mounted below the hole.
Use your little finger to reach it.
4. Set the switch to the desired position.
5. Replace the input module.
SENSITIVITY SWITCH INSIDE ACCESS HOLE
1.4 V |
26 dB |
0.77 V |
Figure 3.9 Input Sensitivity Switch
3.8 Connect to AC Mains
Connect your amplifier's power cord to the AC mains power source (power outlet).
WARNING: The third prong of this connector (ground) is an important safety feature. Do not attempt to disable this ground connec- tion by using an adapter or other methods.
Amplifiers don't create energy. The AC mains volt- age 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 10% variation above or below the amplifier's speci- fied line voltage and within the specified frequency requirements (indicated on the amplifier's back panel label). If you are unsure of the output voltage of your AC mains, please consult your electrician.
3.9 Startup Procedure
Use the following procedure when first turning on your amplifier:
1.Turn down the level of your audio source.
2.Turn down the Level controls of the amplifier.
3.Turn on the Power switch. The Enable indicator next to the Power switch should glow. The amber ODEP lights should also be glowing.
4.Turn up the level of your audio source to an opti- mum level.
5.Turn up the Level controls on the amplifier until the desired loudness or power level is achieved.
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.
4 Operation
4.1 Precautions
Your amplifier is protected from internal and exter- nal faults, but you should still take the following precautions for optimum performance and safety:
1.Before use, configure your amplifier for proper operation as described in the Setup section of this manual. Improper wiring can result in seri- ous operating difficulties. For advanced setup techniques, consult Crown's Amplifier Applica- tion Guide available online at www.crownau- dio.com.
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.Never connect the output to a power supply, battery or power main. Electrical shock may result.
5.Tampering with the circuitry, or making unau- thorized circuit changes may be hazardous and invalidates all agency listings.
6.Do Not operate the amplifier with the IOC LED constantly flashing bright green.
7.Do Not overdrive the mixer, which will cause clipped signal to be sent to the amplifier. Such signals will be reproduced with extreme accu- racy, 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 premature clipping and speaker dam- age.
Crown is not liable for damage that results from overdriving other system components.
page 10 | Operation Manual |
