Partyline: Wiring up a Four Channel System MS-440- SB-440

Over the years, as systemsgrew and more cables were laid closer and closer together, currents were generated (as in eddy currents) and crosstalklevels inch up and channel “A” hears  channel “B” etc  -- not good. Eddycurrents (also called Foucault currents) are currents induced in conductors,when a conductor is exposed to a changing magnetic field such as modulating audio (ACvoltage) due to relative motion of the field source and conductor;or due to variations of the field with time. This can cause a circulating flowof electrons, or a current, within the body of the conductor. Thesecirculating eddies of current have inductance and thus induce magneticfields. These fields can cause repulsive, attractive propulsion and drageffects. The stronger the applied magnetic field, or the greater the electricalconductivity of the conductor, or the faster the field changes, thenthe greater the currents that are developed and the greater the fieldsproduced. 
In audio circuits – the result is crosstalk. As we gainedknowledge / experience, we started suggesting installers wire the systems to limit crosstalk – This can be done by moving pin 2 on threeof the four channels to pin 1 ---- on both ends lest you short the power supply toground!  Adding the drainwire to both ends of Pin 1 could add additional crosstalk protection in mostsituations.
Using cables with AWG #18 or #20 where possible -- and not to use AWG#24 cable over 200 feet...   Warning, Pin 1 should never see chassis or earth ground– be sure the drain wire is not touching same.     


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