I have a stereo pair of Sonos Fives. They are connected to a Pro-Ject Debut EVO Carbon turntable, with an extrenal phono preamp (Pro-Ject Phono Box MM). The pre amp is grounded, and everything is set up properly (good cables connecting TT to preamp, and good RCA to 3.5 connecting preamp to the right side Sonos Five). I even upgraded the power source to the turntable, and have everything plugged into the same outlet (via a powerbar, but admittedly not a good one).
Nevertheless...I still get extremely loud buzzing and feedback out of the LEFT Sonos Five speaker on occasion when using the turntable. And I mean LOUD. Sounds like a distorted bass guitar at full volume. I can sometimes fix it by fiddling with the cables at the back of the preamp, but it will eventually come back. Seems to happen more often at higher volumes.
I’m at a loss. Nothing I try seems to work. Do I need to upgrade my cables? My phone preamp? My powerbar? Do i have to avoid using extension cords?
Any advice is much appreciated. I even went to the local Hi-fi store and they had no idea.