Why does the VPI motor thump

@Moryoga ...check my posts above re my Classic TT upgrades which includes, in part, changing out the on/off bypass cap. Ok ... so the dumb stock bypass cap may not work 100% of the time for everyone. BFD.

The fix requires a screwdriver to open up the access port on the underside of the table. It's takes a few minutes to unscrew the 2 wire nuts that connect the bypass cap. Out with the old and in with the new. Screw the access plate back on. All done! And no soldiering.

If it take more than 15 minutes beginning to end ... the owner has all thumbs and no fingers.

IMO, the Classic is a fine sounding table. With a little practice, setting up the cartridge/uni-pivot arm is a snap, ... with a little help from the SoundSmith Intuit gizmo. I can do the set-up in less than 15 minutes in my sleep.

Just a quibble on my part. I think VPI has attracted an unfair number of swipes from a number of fellow A'gon members ... undeservedly in my view. The table is built like a tank and the arm works with most cartridges. It's easy to upgrade. I've changed out the entire uni-pivot assembly to the Classic 3 base and arm; the new bypass cap; plus, a 300rpm motor.

And the VPI folks (Harry, Mat, Mike, Jack and Jason) are always there to help if there's a problem. I always get through on the phone and turn-around with parts is same day or next day.

I just don't get it. I really don't. VPI is an All-American Classic (pun intended). And Stan (Stringreen) likes VPI tables too. :)

The only time I ever had a thump is when the motor cap went bad. I don't have the problem with a variac because there is no turn on / off of the motor, just the switch on the variac. I keep the variac set to 0volts for turn on / off.

You don't have any thump because you're using SDS.

I bought my Classic 2 used from a highly reputable store and then bought my Classic 3 at the VPI factory where Harry personally put the box in my hands. Both of these tables made the exact same noise when hitting the power switch. I have no personal problem with Harry as a person, he seems like a very nice guy but this particular issue is a problem. Customers shouldn't need to do a modification or upgrade to have a product work without problems. I don't think that this qualifies as "VPI bashing", I think its calling a spade a spade.

Have you discussed this with Harry?

Why not blame the preamp? Why not blame the AC cords or the ICs to the phono stage? If the stock cap works for 80% of the VPI tables, I would look long and hard at other components' placement and emi/rf sensitivity as well. Some components do not play well in proximity to some others. I have to be careful with placement of my phono stage and its separate PS to avoid problems like low-level AM radio and various hums reproduced through the speakers. Careful placement away from my amps and especially, the VPI SDS gets me superb sound while sloppy placement gets me mysteries to solve. Some placements I tried while getting to the current one also caused the turn-on thumping, but only when using the switch on the 2-motor/flywheel body rather than the SDS. This does not happen in my current configuration using all the same components and cables.

Solving the problem at the TT end might keep you from finding a solution that is also causing you not-yet-detected problems elsewhere in your system.