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Page 23
MACRO range installation manual. Issue 6
A. DO NOT allow the cable braiding/shield to contact the cable clamp, plug body or fixing screw. An earth/hum loop
will result. This topic is fully covered on page 20.
B. Application of silicon grease to the cable outer sleeve will facilitate easy insertion into the grommet.
C. Be careful when soldering. Avoid bridging adjacent pins of the locking DIN connectors with solder. If pins 4 and
5 are not to be used, break them off to provide extra space for soldering.
Siting
The position chosen for installation of the amplifier will depend upon many individual factors outside the scope of this manual.
However, the amplifier should be positioned as close as possible to the loudspeaker network, to minimise losses. Ideally, loudspeaker
cables should be routed separately from sensitive microphone cables to avoid the possibility of spurious coupling and resultant
oscillation. Please also refer to the following paragraph on ventilation. Choose a position where there is little likelihood of any
liquid being spilled on the amplifier.
Ventilation
Individual mixers and amplifiers in the MACRO range develop very little heat when switched on and not in use. M8/M and M8/MD
units develop virtually no heat in use and need minimal ventilation. Mixer amplifiers and slave amplifiers develop moderate
amounts of heat dependent upon the amount of sound power delivered to the loudspeaker loads. The design of these amplifiers
is such that heat is conducted from the rear panel across the whole of the chassis which is in effect a very large heatsink and
designed to dissipate the heat by convection. However, in order to do this the amplifiers needs ventilation space at least at the
rear and sides. Rack mounting amplifiers in irregular or spasmodic use may be stacked as required provided that there is
sufficient free flowing air at the rear.
If several 250 Watt amplifiers, are mounted in a rack, and used in a demanding application e.g. alarm tone generation, continuous
full power music, etc., then it is likely that the heatsink temperature will exceed 100 degrees centigrade at which temperature
certain components will start to be thermally stressed. This can be inconvenient (or dangerous in an alarm generation system)
and consideration should be given to spacing the amplifiers. A 1U space should be provided between every second amplifier, and
for systems over 400 Watts, forced ventilation should be considered. Mustang FP.2S or FP.2B fan panels and corresponding
ventilation panels may be specified. The amplifiers naturally long operational life may be realised by a cool operating environment.
To summarise, if MACRO amplifiers are to be used at high power levels DO NOT:-
A) install in small enclosed spaces
B) stack in rack cabinets without adequate cooling, spacing, or ventilation
C) install above radiators or near heaters
D) block-in side and/or bottom surfaces
Interference
Steps have been taken in the designs of the range to minimise interference from external sources. The main possibilities would
be -
a) faulty or insufficiently suppressed lighting dimmer
b) incorrectly shielded or earthed lighting dimmer
c) lighting dimmer lines close to signal input lines
d) strong radio/TV transmission immediately adjacent
e) faulty fluorescent tubes or tube fittings
f) unsuppressed heavy electrical contacts
g) stray magnetic fields from other mains equipment adjacent
h) computer, calculator, or related equipment adjacent
The source of interference should be established by elimination and logic, and equipment repaired or modified accordingly, rather
than attempting modifications to the amplification equipment.
Removal of control knobs
Mixer and mixer-amplifier units are fitted with removable control knobs to deter tampering. Remove simply by pulling firmly away
from the front panel. The knobs are of the collet type, and will disconnect the splined spindle from the potentiometer inside the
chassis. The panel holes may be plugged using the blanking plugs supplied. They are a push-clip fit and cannot be removed from
outside the amplifier. The knobs and spindles may be replaced at any time.
Checklist
During the commissioning of the amplifiers in the MACRO range, various options are available to the engineer to enable him to
meet various technical requirements and the operating requirements of the user:
Use of priority or passive operation for input channels
Priority control out to remote relays, lamps, etc.
Individual input module sensitivity adjustment
Bass cut on microphone input module
Timer setting of tone generator modules
Pre-announcement chime level
Optional auto level control adjustment (ALC)
Control knobs to be removed