L-Acoustics LA48A, Руководство пользователя

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L-ACOUSTICS LA48a Manual V1.0 27/01/2003 10
protect condition, the output level has a slow rise time (the effect is like turning the gain up slowly).
Under normal operation, clip limiting circuitry is inaudible.
Note: if the signal is distorted or clipped before it reaches the amplifier, the clip limiter cannot detect
this and will not be activated.
Channel A, B clip limiters can be turned on (or off) by depressing (or pressing) the relevant clip limit
switch. L-ACOUSTICS recommends leaving the clip limiters switched ON (button depressed) at all
times.
Clip Limiter ON = switch depressed (IN position)
Clip Limiter OFF = switch not depressed (OUT position)
5. INSTALLATION
5.1 MOUNTING
The LA48a is two rack units high (2U) and will mount in an EIA-standard 19'' rack. Four mount points
are provided on the front panel of the amplifier for rack mounting.
For permanent installation, the amplifier can be mounted using standard 19'' rack mount rails and/or
slides within the amplifier rack using the four front mount points. Amplifiers may be stacked directly
on top of each other and there is no need for spacing between units. If it is the intention to fill a rack
with amplifiers, we recommend racking is started from the bottom of the rack. It is also
recommended that rear supports are used for amplifiers mounted in the middle of the rack.
For touring or portable sound system applications, it is essential that all LA48a amplifiers are rear
supported in addition to front panel mounting.
Any mechanical damage to LA48A amplifiers used in portable applications without rear support are not
covered under warranty.
For all portable applications, the amplifier should be fixed in the back with a rear support kit (L-
ACOUSTICS part codes: APSUP or MC-RKSUP). The optional accessory MC-RKSUP is designed for
use with the L-ACOUSTICS RK12 amplifier rack. Alternatively, the amplifier support kit APSUP is a
universal rear support kit for any 19'' rack since it is adjustable to accommodate varying rack depths.
Two rear support brackets, two amplifier support brackets, four M4 hex button head screws and four
washers are included in each APSUP kit. The kit integrates the amplifier support bracket with the
amplifier and the rack support bracket with the rack. Depth is adjustable and amplifiers can be
removed from the rack by simply removing the 4 button head screws. APSUP is suitable for use with
all LA amplifiers.
5.2 COOLING
Your amplifier uses a forced air cooling system to maintain a low and even operating temperature. All
fan cooled L-ACOUSTICS amplifiers have front to rear airflow. There are several reasons for this, one
being that there is usually cooler air outside the rack than inside and therefore the amplifiers can run
at higher continuous power levels without thermal problems. Never try to reverse the airflow since
the Intercooler® needs a pressure chamber between the fans and heat sink and this only works in
one direction of the airflow.
Should a heat sink get too hot, its sensing circuit will mute the overheated channel. If the power
supply overheats, another sensing circuit will mute all output channels until the power supply cools
down to a safe operating temperature.
Make sure that there is an adequate air supply in front of the amplifier, and that the rear of the
amplifier has sufficient space to allow the exhaust to escape. If the amplifier is rack-mounted, do not
use covers or doors on the front or rear of the rack.