Though vinyl is one of our most cherished and enjoyed music formats, the equipment used to playback records is - by its very nature - prone to issues and problems that can disrupt your experience. One of the most common issues reported to us is "mains hum", and though this can be a problem it is almost always not down to a faulty turntable; instead it's because there is not a 'true' earth point in your hi-fi system.
All turntables are prone to attract some level of noise, however, most (like all Pro-Ject record players) are engineered to reduce this tendency as much as possible - so you often only hear it with the amplifier volume on maximum and no record playing. When there is a noise that's audible during normal playback it is often due to poor grounding (even with the supplied ground lead linking the turntable to your phono stage/amplifier), and the problem is typically environmental.
To resolve an issue with earth hum, simply take an additional ground lead, connect one end to the junction box on the back of your turntable and the other to a 'true' earth point. Within the hi-fi system, this could be by linking your turntable directly to the amplifier, or outside of the system it could mean linking to a nearby radiator or the metal earth terminal on a UK mains plug. As soon as you are able to electrically join the problematic components in your system, there should no longer be an electrical imbalance and the noise will go away.
Start enjoying your music again!