Why does the VPI motor thump

Well I just installed a new 300 rpm motor and it thumps more than the 600 rpm. It did come with a new yellow capacitor and I did install that. The only carryover part was some type of roundish electric piece with two wire leads. I installed it in the same place.

But all that aside, why is there a sound made through my speakers at all?

I have the same issue on my Classic II. Matt was somewhat offended when I asked him how to fix the problem. He made it abundantly clear that it was NOT a problem with the turntable but rather my preamp was picking up the collapsing magnetic field of TT motor when turning it off.

He said the two solutions are either install a larger cap ( I don't recall the value) or use the mute switch on the pre, which is what he does. That seems to be the easiest solution so that is what I do too.

That thump is why I mute my preamp before turning the motor off. I change LP side, clean LP and stylus, start the motor, wait for the stylus to drop into the groove then I un-mute. No thump through the speakers with the preamp muted. Mofi's explanation about the capacitor issue is a long running problem with VPI motors.

..then why does my VPI turn off silently??

04-16-14: Stringreen
..then why does my VPI turn off silently??

Luck? Or do you use the mute switch too?
No one said that every single motor VPI ever made thumps, but obviously there are enough of them out there on the market that do thump that threads like this are very common. Search the archives here and at AA, you'll see that this is a common problem.