sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Security, Alarms and Paging 25volt vs 70volt

I am just trying to get some feed back on why this is not shutting the 35 watt amp down

I did notice that the volume on the amp is low


so I will remove the 8 ohm speaker & replace it with another similar speaker and I will replace the 35 watt amp with 100 watt amp

They will need more speakers in some of the class rooms so I am planning on changing all the hall way speaker to 2 watts and class rooms to 1 watt or less its an odd building

very small class rooms and the ceiling in the hallways are only about 7 feet high all hard ceiling with some access panels


The part I don't understand is does it make a difference on the 25V (which they are currently using ) or 70v which I have always used when its just one zone

This is all one big loop


The amp is actually in the main building there is just a pair of wires that come across to the speakers
they have a Viking clock control tone generator attached to it as well

I think they are trying to use the speakers to hear the page in areas where they need another speaker


Thanks for all the response !!

25 Volts is not as efficient as 70 Volts. If you're running 70 Volts and the Amp is bigger than 100 Watts it MAY say on the back by the wiring terminals "Class 1 Wiring required". If it does then you should be running conduit or armor for the speaker wire and the amp and speakers should be in a registered enclosure etc. (In other words treat them as if they were 120Volt electrical appliances!)

If the amp says "Class 2 wiring acceptable" then no conduit is required. 25 Volt was created to handle those situations, since it is NEVER Class 1 wiring.

I haven't seen much 25 Volt stuff in the last 20 years.

European PA is usually either 100 Volts or 200 Volts (sometimes 50). Here in NYC we occasionally get a European company who'se opened an office and has spec'ed European PA equipment. We install it, but treat it as Class 1 wiring.

The long and the short is: Run 70 Volts wherever possible.


Sam