radio fuzz

[dougknight]

Just finished my annual inspection and took N625DK up for a check out. RV-9A, O-320 lycoming (areosport)

Left slick impulse magneto was subject to SB2-08 or SB3-08 (not sure which one, info @ hanger). I Replaced both the carbon brush and cam in it.

I now get a “fuzzy” engine noise through the headset when above 1500 rpm. At 2000 rpm it begins to overpower some radio transmissons. It is evident in both head sets which pretty much rules out the possibility of disturbing a headset/mic connection loose during the inspection I would think.

I turned off the ALT field switch and it is still there.

I actually think it is getting better with time. At first it was really loud even down around 1000-1200 rpm as I recall. Is it possible I’m getting this with the new carbon brush and as it “seats” it is getting better contact and thus diminishing the noise.

Anybody else run into anything similar?

Any suggestions welcome.
Thanks
doug