VPI Speed Controller

Hi, hope you are all well. I would like to hear from VPI owners about speed controllers. I have a very old SDS and wonder if the newer ADS is much better. I have the Prime Sig. with the Fatboy arm and Soundsmith The Voice cart, Pass XP25 phono, Luxman L509X, and ML ESL11As. Sounds great except for solo piano which does not sound good at all. I heard that speed stability could be the culprit and wonder if the old controller is the cause. Thanks for any input,Joe.
Other posts are correct, the SDS is better than the newer ADS.  The ADS is cheaply made and has been the subject of many complaints.

However, you seem to be aiming for high performance.  If you want the very best, SOTA sells a motor-controller-roadrunner combo.for VPI tables.  It has been discussed at length in the VPI forum.

Other ways of improving performance would be the motor-flywheel combo, if they still offer it, and the peripheral weight.
@ joeyfed55-    To be more concise:  Here's something to consider, regarding the VPI Prime's maintenance, if you haven't already:    https://www.youtube.com/watch?reload=9&v=AHmYWT3wKqs    Happy listening! 

That was a very  funny video.  Putting oil in the top of the pulley to lube the bearing.  Who is that moron?  He certainly doesn't know anything about turntables or motors.
Agree with the other posters.  Keep your SDS.

Oil will migrate, between the pulley and the shaft, down to the top motor bearing.      Letting the motor run overnight warms things up, and facilitates the process.       The option is to remove the pulley, as demonstrated.                    The, "moron" is Mat Weisfield (current President of VPI), who just might know a thing or two, regarding the maintenance and design of his company’s motors and TTs.                      Of course; that’s just my opinion, regarding Mat.     Thus far; I've been very happy, with VPI's designs/equipment.                                            
Had an SDS with my TNT6 for years - loved it!