IPO Overhead paging feedback

[ecs99ny]

Anyone had any issues when hooking an IPO up to external amp for overhead paging. We are using an analog port set as a page port. System is properly grounded. When we hook it to the amp we get a high pitch noice that sounds like your ears are ringing. The common denominator is the IPO. We have had several systems that when powered up out of the box have the same sound. When hooked to an amp for paging that sound sounds like it bleeds through the overhead paging. Thank you!

 

[Greybeard191]

are you using an 600 ohm isolation transformer? Could be an impedance mismatch. connections to a paging amplifier via either an analog station port or analog trunk port require an isolation transformer.

GB

 

[amriddle01]

Indeed, the issue is incorrect connection/not understanding the requirements

http://www.ipoffice.tel

 

[ecs99ny]

Yes we have a 600V isolation transformer in line. As soon as we pull the cross connect from the analog port sound goes away. We may try Viking Feed back eliminator.

 

[Greybeard191]

600V or 600 ohm?

There is isolation and impedance matching at work here.

GB

 

[ecs99ny]

We tried putting a Atlas LT600v in line. No luck. When I clip my test set directly to my analog port I still get the same "ear ringing" sound which tells me it seems like an audio problem and not a mismatch. Ended up putting in a Viking FBI.