Loud thud heard through speakers

I noticed yesterday a thud through the speakers when I turned the electric oven off in the kitchen, which is around 8m from the turntable. No record was playing at the time but the MC phonostage was selected and I’d left the volume turned quite high. I used to get a similar noise in my last place when the fridge compressor started up. I think it stopped when I had a dedicated spur fitted but that coincided with moving the system 4m further away. I also used to pick up some radio broadcast in Russian at a low level but that stopped when I replaced my Target rack with something less metallic.