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Mon newpg7.doc – Dangerous Music Monitor User Manual

Page 7

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Balanced Audio Connections

The beauty of balanced connections is that they promote the idea that current should be

prevented from flowing down cable shields while letting the audio pass. Pins 2 and 3

carry a signal across them (transverse mode) and any interference that gets through the

shield is picked up equally by the wires (common mode). The common mode noise is

canceled by the differential action of the instrumentation amplifiers in the first stage of

the Monitor. Signal gets through and the grounds stay put inside their respective pieces of

gear.

Unbalanced Audio Connections

An unbalanced source driving a Monitor input usually presents no problem

because of the differential action of the input stage.

It is a good idea to use 3 wire cables even in an unbalanced situation because the

Monitor input can keep stray noise away from the signal even without the benefit of

common mode rejection. If an unbalanced source gives one trouble, then this is usually

because the source doesn’t have a proper ground reference. This is why there are Input
Shield Lift

jumpers inside the Monitor (and many other pieces of professional audio

gear).

The next section covers how to access the jumpers and how they work.

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