Electrical Squeal

[ppocock]

I flew my RV-7 at night for the first time last week, and as I add lights and pumps, etc, I get a progressively louder squeal/whine through my headsets. Where should I begin to debug, or shield out this noise? Thanks,

Paul Pocock

[vlittle]

Originally Posted by ppocock

I flew my RV-7 at night for the first time last week, and as I add lights and pumps, etc, I get a progressively louder squeal/whine through my headsets. Where should I begin to debug, or shield out this noise? Thanks,

Paul Pocock

Paul, a couple of questions:

- is your alternator internally or externally regulated?
- if externally regulated, which regulator are you using?
- are you using electronic noise cancelling headsets?

Thanks,
Vern

[tomcostanza]

It sounds like alternator noise. You could try momentarily turning off the alt field switch/breaker and see if the noise goes away. That would confirm or eliminate it as a source of the noise.

[Brian Denk]

Also if the frequency of the noise changes with throttle setting, you know it's alternator related. I had the same issue. Installed a Rad Shack filter/choke kit...capacitor and transformer. Can't remember exactly where I put it, but it worked!

Haven't heard a hint of whine since that was done. If there is whine, there should be cheese too.

[ppocock]

Thanks for the input. I have the FWF 60amp alternator which is internally regulated, and use noise cancelling Lightspeed headsets.

Paul Pocock

[vlittle]

Originally Posted by ppocock

Thanks for the input. I have the FWF 60amp alternator which is internally regulated, and use noise cancelling Lightspeed headsets.

Paul Pocock

Paul, if you have a passive headset, see if you get the same problem. I had a similar problem with a DC headset with an aftermarket ANR. I never did fix the problem, but I'm sure a simple noise filter (capacitor) on the headset power lead would have helped.

I ended up switching to a Halo headset, which has no problem.

Vern