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!