Simplex speaker noise

Has anyone fixed a wining noise generated in simplex fire alarm speakers?

Sounds like it could be a bad filter capacitor. Don’t quote me on this. I’m sure a Simplex technician will reply to this soon as well.

What is the model and variation of the panel? A single panel? Transponders? Network audio? Knowing this helps in troubleshooting.

A constant signal of about 1 KHz would be supervision tone leaking into the speaker circuits somehow. A clicking noise like a high speed Morse Code sound usually is caused by poor shield management on twisted shielded cables or incorrect shield termination in the panel. Power supply filtering problems would generate a 120 Hz tone from FWR power not being filtered enough.

Panel is a model 4100 with transponder panels and nac panels. 18 story building, A lot of speaker circuits but only one circuit has a constant wineing noise just loud enough to be a problem. Thanks

Hello darkness smile friend.

Anyways, usually this type of problem from the way you described it is crosstalk between the speaker wire and SLC wiring. On my YouTube channel I have posted a video with an example of that. Usually if the problem originates in one place when two wires are close to each other it isn’t usually hard to fix. But when the crosstalk is originating almost everywhere it can cost a lot to rewire. You have to make sure the wires are separated when installing the system. Remember, the sound starts when SLC and speaker wires are too close to each other.