Voltage Regulator
 

Has anyone experienced com radio noise due to problems with the voltage regulator. I don?t know if I have a regulator going bad or not.
I have battled com radio noise and tried everything the experts have given me. Somethings have helped but nothing has solved it. Knowing there are many problems with the regulator that?s been reported and wondered if anyone had seen it affect the COM noise.

What model voltage regulator do you use?

It'd be helpful if you described the noise. ex: Does it change pitch with engine rpm? Do volume controls on the various affected audio 'boxes' affect noise volume? Is it a consistent noise, does it vary in characteristics, is it 'static' sounding, or a whine? etc etc.

I got an increasingly bad whine/buzz in my headset for a couple of weeks before all the magic smoke escaped from my original Ducati regulator.

965 349 Rectifier Regulator
GTR 200 Com
It?s a static sound and it normally starts after about 15 min. into the flight after after the aircraft systems warm up.
The noise stops when the throttle is closed for landing and the ground operation. During phase the battery is supplying most of the current as the alternator supplies little at the lower RPM.

Newer regulators for PM alternators are 'switching' style regulators, so the static sound could be coming from the regulator (which includes the diodes that convert alternator AC to DC). But don't ignore the possibility of wiring/grounding issues.

If the problem is a recent development, I'd lean toward the regulator. If it's always been there, it increases the chance that it's installation related.

Easiest troubleshooting path is to substitute a known good regulator (you could try a cheap one off ebay).

Com Noise
 

I too have the same problem. The background noise is tied to the engine RPM and increases with strobe and landing lights. The noise oscillates with the strobe function. I do YouTube videos and in post production editing I clip out the noisy portions of the sound track. We are on our third ducati Voltage regulator. The aircraft has 565 hours total time. It is an E-LSA and we are planning a John Deer VR replacement for the Ducati when it goes Tango Uniform.

When the aircraft was new late 2017 & 120 hrs ago the noise wasn?t there. I?ve worked on this problem about a year now. I first went through all the grounds and antenna connections and that didn?t help. Most of the grounds go through the 50000 box and it?s mounting surface. With the release of the RV-12iS Vans no longer supplies that mess. Anyway after about 15 mins in the air the noise starts soft and builds loud.
After following every lead I could find including many calls to Vans & Garmin I found nothing that would help.
Recently I started adding noise chokes to the wire bundles. This has helped and the more I added the better it?s it gets but I?ve run out of places to add lmore.
It?s better but still quite bad. It?s reported that all my transmissions have always been perfect.
I don?t seem to have any problems on the ground or when I close the throttle for the landing. Note, that?s when the alternator is putting out less power.

Are the audio jacks physically isolated from the the airframe with insulating step washers?
Ground the voltage regulator case to the airframe with a heavy wire.
If music jacks are installed, disconnect them at the instrument panel end.
As a last resort, try powering the radio with a DC to DC converter.

If you have any associates with Extra Ham Radio licenses, I'd contact them for assistance in isolating the problem. Dx contester types are particularly good at isolating problems like this type of RFI.