T+A Elektroakustik PA 820 M - Handbuch (Seite 46)

46
Installation
Using the unit for the first time
Safety notes
 This section covers all the really important aspects of setting up the system and operating it for the first
time, but which are not relevant for daily use and handling the equipment. This information is important, and
must be read carefully before you use the system.
Connections on the PA 820 M
    Loudspeaker terminals
Two pairs of loudspeakers can be connected to the two
loudspeaker outputs
    A (FRONT) and     B. The
impedance of each speaker must be no lower than 4 Ω Ω Ω Ω.
Note:
If you only wish to use one pair of speakers, the
loudspeaker terminals can also be used for 'Bi-wiring',
a form of connection which provides even better sound
quality (see 'wiring diagram 1b').
Loudspeaker cables can have a crucial influence on
the quality of reproduction of your system. The speaker
terminals can accept cable with a conductor cross-
section of up to 7 mm². We recommend using high-
quality cable with a cross-section of at least 2 x 4 mm².
Please ask your specialist dealer for advice on this.
It is important to ensure that the speaker terminal
clamps are tightly screwed down, and that there are no
stray strands of cable or conductor sticking out.
Note:
If the loudspeakers are to be used in countries outside
the EU the red/black stoppers can be removed from the
loudspeaker terminals. The speakers can then be
connected using banana plugs.
The stoppers are simply a push-fit in the terminals, and
can be prised out from the rear using a suitable tool
such as a knife blade.
    Cooling fan
The PA 820 M’s intelligent micro-processor controlled
cooling fan continuously monitors all the operating
parameters of the output stages and the mains power
supply unit.
Temperature data is measured at several points, and the
machine uses this information together with load and
output level data to calculate a requirement profile for
cooling fan power; the output of the fan is set to one of
three stages accordingly.
This method of regulation enables the PA 820 M to deliver
high output levels for several hours continuously without
problem and without overheating.
At the other extreme fan power is reduced in quiet music
passages, keeping the output stages at the optimum
operating temperature for sound quality. Fan noise is
minimised at this setting.
   
The fan must never be blocked by cables etc.
Ensure that the fan blades are free to rotate,
and cannot be obstructed.