I go back a little. Back when I was installing crossbar PBX, the page port was always a station port of 900 ohms. The amplifiers were all tube type and, fresh out of the box, they had 5-10% distortion. They usually had one "input" and it was between 10K and 15K ohms. A matching transformer had to be used, no exceptions.
With the advent of electronic systems, Key and PBX, the output is usually provided to match a 600 ohm amplifier input. Some dinky systems have an 8 ohm output and they, usually, require a matching transformer.
We have paging systems in chemical plants and coal mine offices. The voice quality has to be absolutely clear as specific emergency instructions are announced via PA system when an emergency occurs. They will not tolerate ANY distortion, so it has been a pet project of mine to make sure everything matches and the distortion is kept as low as possible. That is why we have Tektronix scopes, distortion meters and spectrum analyzers. That is why I am obsessive about matching impedance parameters. Hal is correct in stating the situation is system specific. As he suggested, hook it up and if it sounds good, walk away. If you have hum and/or distortion, find the correct matching transformer that will resolve the issue and ALWAYS keep the level below overload which is the primary cause of distortion in most PA systems.
Rcaman
