My tt has developed a hum and I can't track it down. It happens with the needle of the Ortofon 2M Red touches the vinyl, regardless of the tt being turned on or not. I've checked the ground wire on both the cart and the tt as well as all interconnect connections. I even tried switching ic's out to see if a cable went bad to no avail. My friend thinks the cart or stylus has gone awry, but it's only a couple of years old.

Any help would be appreciated, thanks!