Since this is a Valcom system, there PROBABLY is no central amplifier, unless the Valcom speakers were added on because the customer 'ran out of amplifier', so to speak, and didn't want to plunk the bucks for a bigger amp. I don't agree with the statement that Valcom amps in the speaker are 'cheap', their clarity and gain are excellent. The hiss is 1 of 2 things, running wide open with no audio, or amplifying unterminated noise from the KSU. Probably both. However, if the Valcoms must be run wide open to get maximum coverage, 'ya gotta do what ya gotta do'. If that's the case, ONE, they need more speakers, and TWO, it must be a real thrill to be within 15 feet of a speaker when a page happens. OUCH! You may want to talk to the customer about potential OSHA fines if an unhappy employee, x or therwise, files a complaint!

When I was young, I was Liberal. As I aged and wised up, I became Conservative. Now that I'm old, I have settled on Curmudgeon.