2. analog
  3. 137140-35975

Questions about VPI Turntables and rotational speed

I've noticed that my VPI Prime Scout is not as good as I'd hoped at rotational consistency.  This has been measured by two different iPhone apps on my X.  Now, I can get it to stay around 33.33 RPM, but it seems to have a fair bit of flutter.  My thinking is that this could be caused by the relatively heavy weight of the iPhone X in a relatively small part of the turntable, whereas vinyl would produce relatively light weight, in across the entire platter.  Does this sound right, or is the weight of the iPhone probably inconsequential?

That said, I know there are devices made by VPI (i.e. the SDS) that will cause a more optimal signal to the motor.  However, I also know that speed may be varied fairly significantly by moving the motor closer, and further from the center of the platter.  So, given this non-fixed ratio, how does the SDS serve to make a better signal for the VPI?

Thanks!
tre9901
sturgus
68 posts
 
How accurate is the app? I think I would try a good printed strobe to see how it compares. Sometimes simple is better.
miner42
709 posts
 
There there are very knowledgable members at the VPI Forum site who would answer your question to the most finite detail.  I enjoy that sire very much.
bifwynne
2,206 posts
 
tre9901 - agree with Sturgis.  I own a VPI Classic "2.5" (sic).  I never checked the rotational speed or flutter of my platter.  That said, I agree with tre who advises that you check your speed with a paper strobe.  

Btw, is the TT perfectly level in all dimensions?  That's important. If you still believe there is a flutter issue, think about a new belt. That's the cheapest option.  SDS and/or a new motor is the next step ... and will cost bucks.  

As far as the motor is concerned, I was able to swap out the stock 600 rpm motor that came with my standard Classic for the 300 rpm motor that came with the Classic 3.  Easy as pie and soldering is not required. Just wire nuts.
More to discover