Crest Audio CPX 4, Руководство по эксплуатации, Страница: 6 / 18

6
The CPX 4 amplifier has a combination AC switch/circuit breaker on the front panel. If the switch shuts off
during normal use, push it back to the ON position once. If it will not stay on, the amplifier needs
servicing.
INDICATORS
The CPX 4 amplifier features three front panel LED indicators per channel: GCL, SIGNAL and POWER, plus
a shared Thermal Protect LED. These LED indicators inform the user of each channel’s operating status and
warn of possible abnormal conditions.
THERMAL PROTECT LED
This indicator illuminates when the thermal sensor on either heatsink reaches approximately 90 degrees
C, at which point, the amplifiers are muted while the fan remains on high speed. If this happens repeat-
edly, either reduce the load on the amplifier (detach one of the speakers), or supply additional cooling
to the amplifier, such as a fan. When rack mounting, it is helpful to leave 1 RU open above and below the
amplifier to prevent heat buildup from adjacent units.
GCL (Gain Comparator Limiting) LED
A channel’s GCL LED will light at the onset of clipping. If the LEDs are flashing quickly and intermit-
tently, the channel is just at the clip threshold. A steady, bright glow means the amp is clip limiting,
or reducing gain to prevent severely clipped waveforms from reaching the loudspeakers. See the
Gain Comparator Limiting
section for more information.
SIGNAL LED
This LED lights when its channel produces an output signal of about 1 volt RMS or more. This signal indicates
whether a signal is reaching and being amplified by the amplifier.
POWER LED
The Power LED indicates that its channel is operational. It lights under normal operation and remains on,
even when the channel is in Gain Comparator Limiting or GCL gain reduction.
INPUT ATTENUATORS
Whenever possible, set the attenuators fully clockwise to maintain optimum
system headroom. The input attenuator controls, located at the front panel
(one for channel A, one for channel B), adjust gain for their respective ampli-
fier channels in all modes. See the specifications at the end of this manual for
standard voltage gain and input sensitivity information.
AC POWER INLET:
Front Panel
1
2
3
4
5
6
3
2
4
5
6
1
When operating in the Bridged
Mode, both attenuators must
be in the same position so the
speaker load will be equally
shared between the channels.
See the section on Bridged
Mono operation for more
information and precautions.
TEMP
PWR
6
16
20 23
26
29
32
6
16
20 23
26
29
32
SIG SIG PWR
CPX 4
POWER AMPLIFIER
GCL
TM
GCL
TM
TM
PWR
ON