Why does the VPI motor thump

It's a thoroughly avoidable problem- that's why it's annoying to encounter in a turntable that frankly is not cheap. There is absolutely no sonic trade off using the larger cap in the first place. As mentioned above it's a 25 cent part.

Yes, you can use the mute button but- 1- we sometimes forget; 2- it's an unnecessary extra step that's really a work around for an inadequately engineered product.

I like VPI designs (and I have a 16.5) but ever since first auditioning an HW-19 perhaps 20-25 years ago, I've been skeptical of VPI as well and nothing over the years has changed that impression.

I asked my local VPI dealer once why VPI does not install the bigger cap right from the beginning so we can avoid this problem. I was told that the big cap does not totally prevent the problem either as some systems will have the same problem with bigger cap rather than the smaller cap ( I don't know if this is really true but it is what I was told anyhow) so it seems like there are 2 versions of the cap and VPI installed the one that should work with the majority of the system (80% per VPI)as standard. If this is the case, I don't see that it is any different than certain preamp that needs to be turned on before power amp otherwise you can get a big thump as well if you turn it on after turning on power amp and I would not think that that preamp is crap either!

Ok ... I pulled my VPI Classic out of the trash and against my better judgment turned on the TT with the rig set at full volume -- no mute -- to see if there was a thump on turn-on. No thump. Oh well ... guess I'll keep this pile of junk for a little while longer. I know it plays great music, but I can let thump-free great performance get in the way of the "unfav" comments above. :)