SoundCraft Audio Mixing Console Model Spirit Studio manual Balanced and Unbalanced

	3 POLE (stereo) JACK				2 POLE (mono) JACK
Send			Tip	Hot(+ve)	Left Signal	Signal
Return		Ring		Cold(-ve)	Right Signal
Screen	Sleeve			Screen	Ground	Ground

Tip

Ring Sleeve

Insert Points

Line Input

Aux Outputs

FX Returns

Headphones

Unbalanced

Input

used in several configurations as shown in the dia- grams below.

Balanced and Unbalanced

All channel inputs are balanced, i.e. there are separate +ve(hot) and -ve (cold) wires for each signal plus a ground. The design of the differential input amplifiers is such that interference picked up on these wires is can- celled out. This is because, since both wires are in close proximity, the same interference will be picked up on each wire and balanced input amplifiers will only amplify the difference between +ve(hot) and -ve(cold). Any signal on both hot and cold (i.e. noise) will not be amplified - this is known as common mode rejection (CMR.). If using an unbalanced source into a balanced input, it is a good idea to connect the source ground to the negative input. Should the source device have no connection to mains ground, then connect the shield at both ends. If there is a connection to mains ground, then the shield should only be connected to the source device ground.

Note: many modern audio/musical instruments have electronically balanced outputs which should not be unbalanced by shorting one wire to ground. Always use your inputs balanced where possible.

The mix, group and auxiliary outputs are ground com- pensated and provide a very effective way of optimising noise immunity, without the cost and com- plexity of balanced outputs. These outputs employ ground compensation techniques to cancel out the ef- fects of variation in ground potential between the mixer

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