Hi folks, looking for more advice here!!

Here in work, we now have 8 100v line speakers fitted in the celing, can't remember off hand how many watts each is, I need to get an amplifer suitable, and its gotta be cheap, would be great if it was either tiny, of 19" rack mountable, any help?

Ollie

This search page has quite a few that may be suitable

100V systems are different from normal systems. The power output of the amplifier must be GREATER than the power rating of the speakers. Generally the speakers are only 5 or 10W or less for internal use

I've use Adastra amplifiers at work and they seem pretty robust. They are also rack mountable and aren't terribly priced. One of the ones I've fitted in particular has 70 or so firemen using it day in, day out and it's rock solid.

Please can somebody clarify: I was recently told the opposite of this - that in a 100V line system, the amp MUST NOT exceed the total power of the speakers, and it should, in fact, EQUAL it, as closely as possible. For example, I have 8 x 15W speakers installed in a dining hall, which equals 120W so that is the size amp I have used. Is this correct? As I also wanted to include 2 x 30W speakers for one end of the room (making 180W), but the next size amp available would be 240W, so if I can over-size the amp safely this would be fine, otherwise not?

There's a bit of information here http://www.theelectronicsshop.co.uk/Infoma...oudspeakers.htm and here http://www.ukslc.org/articles/sound/guide_...pa_systems.html

Google is your best friend

Matt

Since the days of Vivian Capel's Public Address Handbook - which I bought in the early seventies when still at school, the accepted practice is that the amplifier power rating sets the maximum and then you have freedom to hang whatever speakers you like, at whatever volume tap you like, across the line, as long as the total of the tap settings is less than the amp maximum. That, of course, is the entire point of 100V line distribution - a speaker can be loud or quiet, set at the loudspeaker not the amp!

Thanks, paulears - means I can buy the larger 240W amp with no worries.

"Google is your best friend" - must be the most over-used phrase on Blue Room. Yes, it's a friend, but it's not a definitive source of facts.

Google's a good source of initial facts and maybe support for something you're 99% certain of isn't it - but the errors, usually either well intentioned, or just plain lazily compiled make it troublesome. I've spent some time today attempting to find out some facts for someone on a job in Costa Rica - and have conflicting info in balanced amounts!

It's probably worth noting that it's common for 100V systems to be run in zones - so the amp ratings aren't quite so important. When you have too many speakers, then just get another amp and start a new zone. The other hing is that with so many speakers, a cable fault can kill the lot - so a kind of star distribution system that can be switched out - arm, by arm, is also useful for preventing faults killing the entire thing.
Paul