L-Acoustics LA48A, Руководство пользователя

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L-ACOUSTICS LA48a Manual V1.0 27/01/2003 11
For installations with a central cooling system (usually found in fixed installations with a dedicated rack
room) it may be necessary to calculate the maximum heat emission. Please refer to Sections 5.6 and
5.7 concerning Power Consumption and Heat Power Calculation.
5.3 OPERATING VOLTAGE
WARNING!
A label just below the mains cable on the rear of the amplifier indicates the AC mains
voltage for which the amplifier is wired. Connect the power cable only to the AC source
referred to on the label. The warranty will not cover damage caused by connecting to the
wrong type of AC mains.
L-ACOUSTICS switch mode amplifiers use primary switching, i.e. the mains power is rectified directly
before the transformer, which means that the power supply is insensitive to the mains frequency and
will operate from DC to 400 Hz.
The amplifier is supplied with an approved European AC line connector. If this power plug is not
appropriate for your country, it can be cut off and wired to a suitable connector in the following manner:
BLACK or BROWN LIVE
WHITE or BLUE NEUTRAL
GREEN or GREEN/YELLOW EARTH
Once the AC connector is connected to a suitable AC supply, the amplifier can be started with the
power switch. When you power up the amplifier it takes a couple of seconds to check its circuits (this is
known as the soft or slow start sequence), the fans then blow at high speed before going into idle and
the two bottom green LED’s come on to indicate that the output circuits are receiving the correct rail
voltage.
5.3.1 DENMARK
National deviation concerning installation of the LA48a:
Danish safety regulations stipulate the use of an 8 A mains fuse. Since the LA48a uses an internal
primary mains fuse of 15A, the LA48a must be equipped with an industrial mains connector rated for
16 A or, alternatively, be installed to a fixed 16A circuit.
5.3.2 SWITZERLAND
National deviation concerning installation of the LA48a:
Swiss safety regulations stipulate that a type 23 mains connector must be used.
5.4 GROUNDING
There is no ground lift switch or terminal on this amplifier. The signal ground is always floating via a
resistor to chassis and the grounding system is automatic. If a potential above 0.6 V presents itself
between signal ground and chassis ground, a short circuit is introduced between the two, thereby
enabling electrical protection. If a unit in the system is faulty, its mains fuse will blow due to this
automatic ground system.
If you wish to tie the signal ground to chassis, connect the XLR-connector’s shell lug to pin 1. In the
interest of safety never disconnect the earth pin on the AC power cord.
For all units that are CE-approved (radio interference), there is an AC mains filter. This filter needs the
chassis ground for reference, otherwise a current loop is formed via the signal ground.
Use the balanced inputs to avoid hum and interference.