Dear all, this is my first post so hello everyone. I have a grounding issue on my setup. I have a Pro-Ject Carbon and an Audio Analogue Primo Settanta amplifier - that's the only thing I have connected. Everything worked fine for a few years, but lately I am hearing a ground noise (like a whistle) as soon as I turn the amp on and select the phono input. Turning the volume up also turns the noise up. I checked all the cables and everything seems fine. The only thing I've been able to detect is that, by touching one specific cartridge connector on the tonearm with a mains tester, the noise goes down substantially. I made sure they're well inserted and everything looks fine. Now the weird part. This only happens in the mornings, up until about 4/5pm. After that time everything works fine, everyday. I suspect there's some sort of machinery in my block that goes off at that time, but I have no idea what it could be. Thanks for your help!