Technically, a shielded cable is actually a capacitor. Think about it and it makes sense. You can cause more problems with shielded cable than you can solve. An amplifier is designed to output into a resistive or inductive load, not a capacitor. Eventually, if the conditions are right, the shielded wire could provide an induced emf back to the finals in the amp and wipe out the transistors.
Some systems, however, are designed with a shielded output in mind. I am reminded of the old nurse call systems and Valcom talkback systems. Both were designed to use shielded cable.
Regarding the new addressable fire alarm panels, I would highly recommend using shielded cable and make sure you separate input pairs from the output power pairs. It makes a VERY big problem if you do not.
Rcaman
Last edited by Rcaman; 11/13/13 09:42 AM.
