VPI SDS capacitor question

I just got a response from Mike telling me if there is no problem to leave it alone and count myself as lucky. The obsessive audiophile in me would like to fully understand why my Classic does not have this problem, but I'm going to let it go.

Thank you all for your input and advice.

It was bugging the heck out of me so I did the swap, but I don't think lack of that cap alters performance otherwise.

If it's not broke, don't fix it. If it sounds good, leave it alone.

I don't believe I've experienced any of the issues described. I've always given the platter a finger spin as I turn it on, even before I got the SDS, so that there is less pull on the belt. I still do it with the SDS so that it hardly ever displays 115V; it simply stays at 72V, unless I've had too much Scotch and don't time the finger spin right. It goes to 115V on startup and then 72V after a few seconds.
The only "pop" I hear is when I turn the table off, but I simply turn the volume all the way down before doing it, and no pop is audible. It has become part of the process.

I guess my question is whether I need the capacitor at all, and how do I determine if I actually need it? To put it differently, is my SDS not performing as designed without the correct capacitor?

I also have the SDS with the Classic and VPI changed the capacitor to the .68 version. Hope this helps.

This is the message I got from Mike at VPI about the cap:

"Your Classic has a 600 RPM motor that  uses a .5 microfarad capacitor to start, when using the SDS you really need to change that cap to a .68 otherwise the SDS is fooled into thinking there is nothing there."

To the OP - you wrote that you have the Classic and SDS already. Do you not have that startup issue (where sometimes the motor doesn't run at the higher initial voltage long enough to get the platter moving before it drops to the lower voltage)?

You can get them at any parts supply for a buck or so; I forget the value, it should be one here in the archives. I replaced it on the only Classic I have sold so far as the standard cap was giving a loud pop when turned on; no SDS was involved. Very easy to replace; just took me a few minutes and I have slowed down a lot the last few years.

This is true. I have a Classic and got an SDS a couple of months go. VPI said there's a capacitor inside the Classic that "fools" the SDS into not "seeing" the Classic properly (I can't explain the technicals of that). Basically it causes the SDS not to give the motor enough juice to start up. I usually had to give the platter a little push on SDS startup because of this.

VPI, or your dealer, can send you the cap. It's really easy to swap, and then the SDS will work properly.