jbDC9
Well Known Member
Has anyone had issues with P/Emags causing audio noise over the intercom?
Backstory; I've been running Pmags since new, 13+ years and 1650 hours... my panel was straight from the locomotive era with nothing fancy, just round gauges, a Garmin 496 and a KX125 navcom with audio fed straight to the intercom. Never had any noise. But, I upgraded things and some noise snuck in, boooo. Now I have dual G5s, a GNX 375, a GTR 200 com, an Aera 660 GPS, plus the old KX125. I didn't use a traditional audio panel and instead went with the AP-60 audio mixer which I quite like.
The noise is a low level snap-crackle-pop in the headsets; it initially would occur parked with the engine off, but after start would get worse. I tracked down some of the noise to the Aera 660 audio output; once I disconnected the 660 audio, all was quiet, yaaaay. Then I started the engine and the noise came back. Now it only occurs when the prop is turning; thinking it was a dying alternator, I replaced with a new one. No change. The noise is still present even with the alternator CB pulled. Next up was new NGK spark plugs. Noise still present. The spark plug leads are fairly recent, just three years old...
When I disconnect the AP-60 audio feed to the intercom, all goes quiet, so whatever the noise source is, it's affecting the audio mixer. So, now I'm stumped. I think it's the Pmags, but how do I isolate and fix it? Has anyone else run into mystery noise like this?
Thanks!
Backstory; I've been running Pmags since new, 13+ years and 1650 hours... my panel was straight from the locomotive era with nothing fancy, just round gauges, a Garmin 496 and a KX125 navcom with audio fed straight to the intercom. Never had any noise. But, I upgraded things and some noise snuck in, boooo. Now I have dual G5s, a GNX 375, a GTR 200 com, an Aera 660 GPS, plus the old KX125. I didn't use a traditional audio panel and instead went with the AP-60 audio mixer which I quite like.
The noise is a low level snap-crackle-pop in the headsets; it initially would occur parked with the engine off, but after start would get worse. I tracked down some of the noise to the Aera 660 audio output; once I disconnected the 660 audio, all was quiet, yaaaay. Then I started the engine and the noise came back. Now it only occurs when the prop is turning; thinking it was a dying alternator, I replaced with a new one. No change. The noise is still present even with the alternator CB pulled. Next up was new NGK spark plugs. Noise still present. The spark plug leads are fairly recent, just three years old...
When I disconnect the AP-60 audio feed to the intercom, all goes quiet, so whatever the noise source is, it's affecting the audio mixer. So, now I'm stumped. I think it's the Pmags, but how do I isolate and fix it? Has anyone else run into mystery noise like this?
Thanks!