Q2 OPERATION AND MAINTENANCE MANUAL 9601 12
To take full advantage of the excellent audio performance of DDA
mixing consoles, it is essential that the installation is carried out
with care and attention. All audio signals are referenced to the
system earth, which must be clean and noise-free, and essentially
equipotential. In addition, the earth system integrity is absolutely
necessary for safety.
Do not disconnect the mains earth wire from each piece of equip-
ment as this could create a hazardous situation.
If in doubt consult a competent engineer and your local electricity
supply company to ensure that safety regulations are not infringed
or negated.
The console metalwork MUST ALWAYS be connected to the
Mains earth via the PSU lead. However, the user has a choice as
regards the Audio 0V.
The Audio 0V should be taken from the Studio earthing System
which should take the form of a star wired system. Decide on a
central point for the main earth system and starfeed to all mains
outlets and equipment racks from this point. Common electrical
wiring practice is to daisy-chain earth wires from outlet to outlet,
but this is not recommended for audio installations. The location of
the earth system star point should be in a convenient, easily
accessible position, such as the main equipment rack. The star
point must then be connected to the incoming mains earth but
preferably should be connected to a totally separate technical
earth (if local electrical regulations permit).
This should take the form of a large copper plate or stake
buried as deeply as practical into the ground (a 1 metre [39"] cop-
per stake hammered fully into the ground would be suitable).
This should then be fed to the studio star system via heavy gauge,
low impedance cable, with adequate precautions being taken to
prevent excessive corrosion of the cable/earth stake.
GROUNDINGWIRINGCONSIDERATIONS