Why does the VPI motor thump

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. :)

Correction: double checked thump on turn ON. No thump. However, slight pop on turn off, but not a thump.

But really. Who cares? The TT runs dead quiet as best I can tell and my Lyra Kleos tracks beautifully on the Classic 3 arm. Sorry guys, I think this is a lot of nitpicking.

VPI Tweak News: Just installed a 300 rpm motor and new larger on/off bypass cap. To be clear, the 300 rpm motor comes with a slightly larger sized cap than the 600 rpm motor. But I had to ask VPI to send me the larger on/off bypass cap. Absolutely no thumps. The motor is dead quiet. And the TT works just fine.

FYI for other DIY'ers: My version of the earlier Classic plinth has a circular metal disc which is hot glued into the plinth structure directly underneath the 600 rpm motor. Dunno if its the depth of the 300 rpm motor, or just the way the early version Classic plinths were made ... but the metal disc in my plinth had to be pried out or the new motor would not lay flush with the top of the plinth.

Removal required a flat-head screw driver. I just jiggled the metal disc out with the flat-head screw driver. VPI has a round rubber sticky that goes on the bottom of the 300 rpm motor. As best I can tell, the metal disc serves no purpose and the rubber sticky works just fine. Bottom line: no motor vibration or noise. Everything seems to work well.

Btw, this is a good time to clean and relube the main platter bearing with white lithium grease. Not sure I needed to put a tiny drop of oil into the new motor ... but did. Just a very tiny drop.

So ... for those who have a Classic TT with the 600 rpm motor looking to switch to the 300 rpm version, be sure to ask VPI to send along the larger on/off bypass cap and the rubber sticky thingy in the kit.

At this point, the only other tweak to turn my TT into the Classic 3 is the plinth. All other components are Classic 3.

Per Mat Weisfeld, there's not much more I can do to tweak the TT, except maybe for better feet, like Bear Paws. I have a DIY idea which may obviate the need for new feet.

Been thinking about building a sand box sub-base. I would cover the sand with a piece of thin rubber to prevent sand from getting into the TT. On top of the rubber covered sand sub-base goes my 35 pound 2" thick maple slab TT base, which I already own. On top of the maple slab sub-base goes the TT.

P.S. When my wife first saw the maple slab, she didn't get angry because I spent more money on my rig. Instead, she tried to take the slab for the kitchen Fortunately, it weighs 35 pounds and she gave up. :)

P.S.S. -- You may ask, does the new motor effect any improvement. Not sure. If there's an improvement, it's subtle. The main reason for doing it was boredom. Also, I'm sure it will make Stan (Stringreen) happy. :) LOL

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