4901-9816 problem

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Kudlaty771
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Tue Aug 14, 2018 6:42 pm

Hello everyone, I have a question relating to my Simplex 4901-9816. I bought it off ebay, new in box, with the intention of putting it on a 4903-9105 strobe plate. However, when the horn arrived, when powered on, it sounded like it was dying already. Does anyone have any idea what the issue might be? Is it the mechanism being poorly designed? Can it be fixed? Any help would be greatly appreciated.
theboginator
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Wed Aug 15, 2018 8:17 am

How were you powering it? I'm not sure off the top of my head if this is a 12 or 24 volt signal but make sure it's getting the right voltage. If the NAC on the control panel (or power supply) is providing Full-Wave Rectified (FWR) current instead of Filtered DC, that's almost definitely your problem. FWR is a known Simplex signal killer and while System Sensor and other branded devices aren't "hurt" by FWR, almost all A/V signals sound much clearer/smoother on filtered DC. Do a quick forum search for FWR and Filtered DC, there's a lot of great topics here describing how and why Simplex signals in particular are sensitive to FWR and panels that do not have Filtered DC power supplies.
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Kudlaty771
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Wed Aug 15, 2018 6:24 pm

Hello, Thank you for the reply. I was powering it on 24 volts DC, and my panel outputs filtered DC. Its a Potter PFC-4410RC, and with my 2901 horns connected to it, they sound just fine.
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kcin556
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Wed Aug 15, 2018 6:40 pm

The 9816 uses a newer Faraday mechanism, in which a circuit board replaced the mechanical contacts that generated the electromagnet pulses on older models. The older contacts created very smooth and even pulses, so the vibration of the horn's plate was regular and had a clear sound. Unfortunately, the circuit board didn't work out quite as well, and the horns with this design tend to sound really rough.

More likely than not, your horn is operating exactly like it should. These designs just have a tendency to sound really poor.
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Kudlaty771
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Wed Aug 15, 2018 7:05 pm

I was afraid of that... I hoped it would be a fixable thing, but I might just put a Faraday 6120 mechanism behind the grille and just use that... Thanks for the reply.
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