Well known issue with VPI and Rega tables. A cap across the power switch of the right value is the answer. I had that issue years ago when I owned a Rega.
Turntables thump when turning off?
Why? I have used 4 different tables and three phono stages in 2 different systems and all of them produce a pretty loud thump when turning off especially, sometimes when turning on. I have been muting the system each time I turn off as it seems a little much to be letting such a thump reach the speakers. Is there a cure? lift grounds? arrange cables? I was getting a pretty decent hum at times and I've noticed careful routing of the cable to the phono preamp makes a huge difference in this.