I think the open c string is giving a slight howl. That's MY ears and maybe not noticeable to others.
If you turn the amp up, that will probably feed back. I would turn it up till you get feedback, then dial it out. When you go to lower volume, that little howl should be gone.
Ok thanks for the advice i'll play a little knock the bass dial down. Impleased the misi is sounding clean and the amp reverb disguises my singing a bit which is good not sure I'd use the chorus but it's a superb amp my guitar sounds awesome too