Owner`s manual

Amplifier Operation
Module Bay
Ci Power Processing amplifiers come standard with a blanking panel fixed over the
module bay. When a NexSys module is installed in this bay, connection to a network
is made via a standard RJ-45 connector and CAT-5 Ethernet cable. Refer to module
documentation for exact connection and control information.
Module Removal
Only jumper setting changes or module upgrades require modules to be removed
from the amplifier. Contact Crest Audio Customer Service for full details on module
removal. The ‘General Module Setup’ diagram indicates the general setup of the rear
panel module/bay configuration.
Note: Removable modules contain static-sensitive devices; handle
modules only at static-safe workstations!
Replacing or Installing a Network Module
The amplifier must be switched off and unplugged from the AC mains supply before
this operation is undertaken. Two Phillips head screws secure the module to the
chassis. The module is connected electrically to the amplifier with a single multi-pin
ribbon cable. Once unscrewed from the chassis, unplugging the module from this
ribbon cable frees the module for removal. To insert a module, simply reverse this
procedure.
Note: Standard Ci Power Processing amplifiers come with a blank
panel installed in the Network bay. The amplifier must not be operated
without a Network module or blank panel in place.
TourClass
®
Protection Features
Every model in the Ci Power Processing line incorporates Crest Audio’s TourClass
protection features. Derived from Crest’s extensive experience with the world’s
largest sound rental companies, the TourClass group of features sets new standards
in load and amplifier protection.
Active Clip Limiting (ACL)
Active Clip Limiting (ACL) circuitry protects both loudspeakers and audio fidelity
against damaging square-wave clipping. When the amplifier reaches its maximum
output power (the point at which the amplifier would begin to clip), the ACL
circuitry automatically reduces the amplifier’s gain to keep the signal from being
driven into clipping. Situations that may activate ACL include: uncontrolled feedback,
oscillations, or an improper equipment setting or malfunctions upstream from the
amplifier. Normal program transients will not trigger ACL, only steady or excessive
clipping. ACL is virtually transparent in operation and full signal bandwidth is
maintained.
Instantaneous Gain Modulation (IGM)
Instantaneous Gain Modulation (IGM) is an innovative impedance sensing circuit
that allows the Ci amplifier to operate safely into any load. When the amplifier
sees a load that overstresses the output stage, the IGM circuit reduces the channel
gain to a safe level. Like ACL, the IGM circuit is sonically transparent in normal use.
In cases where extremely low output impedance is encountered (e.g. a shorted
speaker cable or speaker driver), the IGM circuit will open the amplifier’s output
relay. This will completely disconnect the output path, protecting both the amplifier
and the load it is driving.