Bringing an old thread back from the dead...
I have an audio noise issue on my RV-8, and I've isolated a good bit of it as coming from my dual Pmag power leads, so I've been wondering if I should run new shielded power wires. But, in searching the forums I find posts like this;
No shielding is required.
So here is the conclusion for the books:
1. Spoke to Brad at E-Mag and he say the P-Mag DOES NOT NEED shielded wire.
2. Also spoke to Stein at Stein Air and he confirmed this.
So now I'm undecided whether I should waste my time running new shielded wires... here's the back story; for years my -8 had a caveman panel with a KX-125 navcom and an intercom. That was it... the "audio out" from the radio went to the intercom and all was well for 1500+ hours; mostly quiet with just a wee bit of strobe noise. But, 2 years ago I did a panel upgrade adding a GTR200 com along with a GNX375 GPS/xpdr. I didn't use a true audio panel, but instead used a Flight Data Systems AP-60 audio mixer. Now, I have noise, a crackly static type. I've isolated most of it to the Pmag power leads; in flight, I pull the Pmag power CBs and the noise is much reduced. So, there IS some noise from the Pmags, but is adding shielded wiring there barking up the wrong tree?
I did find one thing yesterday that I did on the original intercom install; I didn't use the isolating wafer washers on the headphone plugs. I did for the mic jacks as the intercom install drawing called for it, but not the headphones. I went ahead and installed new isolating washers for the phone jacks, but I'm unable to ops check it as my engine is currently missing a few (all...) cylinders... so before I tear into running new shielded wires, do y'all think that the noise might be caused by these missing isolators? Could it be that the new Garmin stuff plus the audio mixer bumped up the noise sensitivity of the system and these missing isolators sorta pushed it over the noisy edge?
I hope the new washers fix it, I really don't wanna waste a day running new wires...
Thanks!