SoundCraft Five Monitor Series User Manual

Page 12

2.4

FIVE Monitor Installation

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To take full advantage of the excellent signal to noise ratio and low distortion of

Soundcraft consoles care must be taken to ensure that incorrect installation and

wiring does not degrade the performance of the desk. Hum, buzz, instability and

Radio Frequency interference can usually be traced to earth loops and inferior earth-

ing systems. In some areas, especially heavily industrial areas, the incoming mains

earth will not be adequate and a separate technical earth for all the audio equipment

must be supplied. However, check with your local electricity supply company to

ensure that safety regulations are not infringed or negated.
The successful, hum free, installation of a system requires forethought, and the estab-

lishment of a set of ground rules, which must be consistently adhered to at all stages

of installation.

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For optimum performance, it is essential for the earthing system to be clean and noise

free, as all signals are referenced to this earth. A central point should be decided on

for the main earth point system, and all earths should be `star fed from this point. It

is common electrical practice to daisy chain the earths to all electrical outlets but this

method is unsuitable for audio installations. The preferred method is to run an indi-

vidual earth wire from each outlet, back to the system star point to provide a safety

earth screen reference for each piece of equipment.
A separate earth wire should also be run from each equipment rack and area, to the

star point. This may or may not be used depending on circumstances, but it is easier

to install in the first place, than later when problems arise.
The location of the star point should be a convenient, easily accessible place, prefer-

ably at the rear of the console or in the main equipment rack.
Install separate clean and dirty mains outlets, wired individually back to the incom-

ing mains distribution box. Use the clean supply for all audio equipment and the

dirty supply for all lighting, etc. Never mix the two systems.
If necessary, to provide sufficient isolation from mains borne interference, install an

isolating transformer. This should be provided with a Faraday Shield which must be

connected with earth.
Never locate the incoming mains distribution box near audio equipment, especially

tape recorders, which are very sensitive to electro-magnetic fields.
Ensure that all equipment racks are connected to earth, via a separate wire back to

the star point.
Equipment which has unbalanced inputs and outputs may need to be isolated from the

rack to prevent earth loops.

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Having provided all equipment with power and earthing connections, consideration

must be given to the method of providing audio interconnection and adequate screen-

ing of those interconnections. This must be done in a logical sequence to avoid prob-

lems and assist in the localisation of problem equipment.

Connect the Monitor system to the console and check for any hum, buzz, or

RFI. Only when you are satisfied with the quietness of the console and the

monitor system should you proceed with the next step.

Connect stereo tape recorders, echo and foldback sends one at a time, check-

ing and isolating any connection which degrades performance.

Connect all other peripheral devices.