Filter
Top Products
15
3 It is always preferable to mount power
amplifiers, which generate a certain
amount of heat, above heat sensitive
equipment, like SM30.If however, power
amplifiers must be mounted beneath the
Control Centre, a heat shield should be
installed above them. This is necessary to
deflect the hot air currents, which could
otherwise cause instability in the SM30
microprocessor controlled units.
5.5 Connecting amplifiers
The SM30 system is intended for use with 2
separate amplifiers, or two separate channels
of a multi channel amplifier. One channel
will handle the ‘call’ signal, and the other
channel will amplify the ‘music’ signal. This
allows the music signal to continue,
uninterrupted, when a call is made to other
loudspeaker zones. It is possible to use only
1 amplifier channel for both the ‘calls’ and
‘music’ signal. This has the disadvantage
however, that any music playing will be
interrupted whenever a call is made,
regardless of the zone(s) to which the call is
routed. Though the SM30 system will work
with any line level input amplifier, the
amplifiers from the Philips SQ45 range have
been specifically designed to take the greatest
advantage of the functions of SM30.
Two Channel System (fig.5.5.1)
Connections of SM30 to two amplifiers, or
two channels of a Philips SQ45 amplifier:
1 Connect both the ‘Call’ and ‘Music’
outputs of the Line Output Module, to
the separate ‘Call’ inputs of the SQ45
amplifier(s).
2 Connect the outputs of the amplifiers
(with two core loudspeaker cable) to their
respective ‘Call’ and ‘Music’ inputs on the
‘Mate-N-Lok’ connector on the Zone
Relay Module of the SM30.
One Channel System (fig.5.5.2)
When using a single amplifier system, the
following steps must be taken:
1 The ‘Call’ and ‘Music’ outputs of the
Line Output Module should be
connected to their respective ‘Call’ and
‘Music’ inputs on the SQ45 amplifier.
The relay on the Line Output Module
will switch the active input of the SQ45
amplifier from music to call.
See the relevant SQ45 amplifier
Instructions For Use for details of this
function.
2 The output of the amplifier has to be
connected to the ‘Call’ input on the
‘Mate-N-Lok’ on the SM30 Zone Relay
Module.
3 Refer to Installer Program step 9 to
program this function.
As previously stated, zones with music will
be interrupted for as long as a call to any
other zone(s) lasts.
Rack Mounting
If the amplifier(s) and SM30 are mounted in
a rack unit, and an ‘earth loop’ occurs
(evident by a 50 or 60 Hz hum through the
loudspeakers) follow the Instructions For
Use given with the SQ45 amplifier for
details of earthing the units.
GB/SM 30 user manual 5/26/98 10:18 AM Page 15