atcomsystems.ca/forum Forums Other TDM Phone Systems Executone-Isoetec Telephones & Systems Medley - Noisy PA port

I have a fully loaded Medley system that has a noisy PA port. There is a constant hum coming through the PA speakers that is very annoying. If I disconnect the PA amplifier from the phone PA port, the hum goes away. The PA and port work just fine, announcements can be made through the phone system over the PA system, it just has this constant hum. I have connected my butt set to the PA port on the phone system with the amplifier connected and the hum is coming from the phone system itself. Any suggestions on how to eliminate this hum?

Thanks!

What type of paging system is it? Bogen? Have you tried an isolation transformer in between to KSU and Amp?
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THe Medley uses the single line port or CO ports for paging.

Which one are you using?

Have you tried changing ports and reconfiguring the new port.

Good Luck!!

I tried installing a transformer between the output and the amp. But that didn't help. I have not tried changing ports. I can try that first.

Thanks!

How can the CO ports be used for paging? I thought that was limited to the two analog extensions (191 and 192).

As far as the hum, I've had this from other types of audio electronics after power surges have blown out small but necessary components (i.e. filter capacitors). This could cause an internal ground loop, because the external power supply is 24V AC, not DC. If the hum is that classic 60Hz tune, the small current leak could be the culprit.

Self-amplified horns or speakers can hook-up directly to a CO port. Put it in its own CO group (7 or 8).
There are also some amps like Bogen that can hookup to CO ports. Depends on the aplication.

So essentially, if it works on 191 or 192, it will work if moved to a CO line? I assume that by pressing 7 or 8 instead of *0, it will not be heard through the telephones (only through the paging amp), and will not be preceded by beeps?

You got it.