Default Strange in call noise while charging

When in call strage noise appears i do not hear it but the ppl i speak with.,..they always telling me wtf happans what is that noise and when i unplug it noise is gone.
Phone is stock 4.1.2 rooted locked BL also i am using the stock charger that comes with the phone. Also no idea what kind of noise it is
Devices:
Samsung Wave 525 (Sold)
Samsung Galaxy mini (Stolen)
Sony Ericsson Xperia Arc S (Sold)
LG Optimus 2x (Broken)

LG Optimus 4X HD 4.1.2 V20B