Trident 88 - Star Grounding Principle

Trident 88 Owners Manual28
Trident 88 Power Supply
Trident 88 40+ Channels
If your Trident 88 console has more than 40 Input Channels, then you will have been supplied with two
Trident power supplies and a power supply combining module. It is imported that both power supplies
are connected to the console via the combining module.
The combining module splits the loads to the two supplies. One power supply will be insufficien to
operate eectively for console sizes 40 inputs and above.
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Trident 88 Star Grounding
By connecting equipment together using the ‘star grounding’ principle it is possible to virtually elim-
inate hum loops from studio wiring. Since the system is quite easy to implement, it only requires fol-
lowing a certain procedure that will soon become second nature. A few moments spent studying this
chapter and following the steps listed below, could pay dividends in the future.
— Step One —
Choose a particular piece of equipment that will be made ‘technical’ earth (in most cases the mixing
console is the ideal choice as it is usually the item that everything else is connected to).
— Step Two —
On all equipment that is connected to the console inputs, connect the earth (sleeve) of the cable carry-
ing the signal at the console end but not the end that connects to the equipment. For example, if it is a
jack lead, connect the sleeve at the mixer end but not at the equipment end.
The only exception to this should be a microphone, as it cannot get an electrical earth by any other
means. The earth should therefore be connected at both ends of a microphone cable.
— Step Three —
On all equipment that is connected to the console outputs, connect the earth (sleeve) at the console
end but not at the equipment end (input).
— Step Four —
Connect the chassis or mains earth of all equipment, to the same point that the console chassis and
power supply earth is connected to. This point is then known as the ‘technical’ earth and should be as
good as it possibly can be. In many cases this will be the earth of the mains socket feeding the console,
but sometimes better results and freedom from refrigerator clicks and pops etc. can be achieved by
making an independent ‘technical’ earth. In many professional recording studios, this is done by burying
a large copper plate at least three feet underground and connecting the ‘technical’ earth point to it. A
less drastic measure is to use the copper pipe of a radiator as the earth reference, as this often runs
underground.
It is essential that if a separate technical earth is generated, this is always used as the earth point for all
equipment. Connecting some equipment to mains earth and some to ‘technical’ earth could result in a
shock hazard, as it is sometimes possible for a quite high A.C voltage dierence to be generated across
the two earth points.