Why does the VPI motor thump

Post Script to Stan (Stringreen): Stan, what are your thoughts if I paint my plinth with a shiny garnet black lacquer? It still won't be a Classic 3, but it may look like one. LOL

BIF

If a variac or SDS is used to manage the motor, there is no start up thump or pop.

I had the pop with both a TNT and an Aries motor. Currently using a variac on the Aries. Totally quiet start up and shut down. I turn on the variac when I turn on the preamp with the voltage set to 0v. I increase to 110 for start-up and and record brushing, then dial back to 60v for playback. When finished with a side, the voltage is doaled down to zero.

I like the very quiet background it provides compared to plugging the motor directly into the wall. Not sure I actually need something like a SDS because the speed seems OK.

Perhaps my system being totally balanced (all XLR connections) including turntable and everything else has something to do with it???

String, you're using a SDS. That isolates the motor. No thump. So does a variac and performs the most important functions of a SDS (isolation and voltage reduction) though manually.

Bpoletti...thanks for the answer