atcomsystems.ca/forum Forums Other TDM Phone Systems Executone-Isoetec Telephones & Systems paging hiss

So the zones work, paging works. The speakers hiss when idle though.
The speakers are kept at maximum volume. All four zones hiss on the speakers. My buttset across Tip and Ring is silent with speakers connected or not. I wired a speaker right at the phone system with only the one speaker hooked up to the power supply, only one zone hooked up, hisses. That's with the speaker and about 4 feet of cabling total between the Valcom power supply (1124), the IDS and the speaker.
This is on an IDS 228. They have it on a small surge protector, no UPS. I don't think there's much I can do about the hiss. I am going to try reversing polarity on tip and ring and seeing if maybe the hiss comes from the 2nd power supply of the IDS. Do you guys have any other thoughts? I can see ending up either adding a V2006A or a RAD 1A or a bunch more speakers...

Your buttset is probably on the amp input right?That's a low level signal.
Try this,hook up a speaker like you did at the IDS and do not connect the IDS paging output to the amp.Do you still hear a hiss? What you are probably hearing is noise from the amplifier.

Its a Valcom system and they use cheap amps in the speakers that will hiss at full volume. It may be caused by an impedance mismatch between the phone system and the Valcom. If they need lots of volume or speakers I would suggest putting in a real paging system.

Actually, you may get rid of most of the hiss by turning the volume down 5 degrees, just turn it down '2 hairs'. Try it, you'll be surprised. If that doesn't help, see if you can clear the hiss by shorting the t and r. If so, you know what to do next. That's right, a set of relay contacts that short t and r when not paging. Often times there is a page relay in the phone system. Usually it is N/O so you'd have to use it to control another relay, but you've got 24V right there. And the page level is low, so you don't need big honker contacts.

Perhaps you have activated background music over page. At the operator station press 83 plus 2 digit external zone number to activate or deactivate. The zone number depends on your numbering system so I think that would usually be 60,61,62 etc if it is on then connecting a music or tone source one of the music inputs should be heard over the speakers.

You said you have the speakers at full volume how about the gain on the amp? You should be able to turn the gain back a little to stop the hissing. If you need the gain and speakers wide open you should probably add more speakers if your not maxed out.

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!

The speakers are 'running wide open'. I don't see there being any other solution than to add more speakers.
They page by zone phones/speakers. If I use a V2006-A, the hiss would go away but they wouldn't be able to page speakers and phones at the same time.
So, more speakers it is.

Well, as I said, you might discuss OSHA visits triggered by employee complaints. Their fines can be ludicrous! WWWAAAYYY more than another dozen Valcom speakers, installed!

https://www.hobbyengineering.com/H2244.html

That would work right? does anyone know where I can get these things already built? I called Black Box and they returned my call to tell me they don't have anyone who knows what a VOX relay is.