The SDS will make your motor run a bit smoother and more quietly. It will also permit you to set the speed very precisely and stably. I found with a similar product, the Walker Audio Precision Motor Controller, that these effects also resulted in a remarkable "opening up" of the midrange, where I could much more easily separate instrumental and vocal lines. I think either device or an analogous one made by the tt manufacturer specifically for his motor is indispensible if you are running a belt-drive turntable. But as the others have said, the symptom you describe is most likely due to an off-center spindle hole. If it happened on every LP, and if you could actually SEE a speed variation using the KAB strobe or similar, I would suggest you have a defective motor or you need to replace your tt belt or tighten it.
Speed Stability
I have been fretting about the speed of my vpi for about a week now. I do not have a test LP or a strobe mat but I feel that if there is a speed issue. I am hearing the pitch fluctuate up and down on notes that are held out. I have compared some recordings to a CD version and have gotten mixed results. For instance:
On the first track of John Coltrane Quartet Ballads, I noticed that the ending note on the the first track tended to sway like an old VHS tape compared to the solid pitch of the CD version.
a first pressing of Dark side of the moon compared to my anniversary CD copy resulted in no significant changes in pitch that I could hear.
I guess what Im trying to get at is could that be a issue with the speed of the pressing itself, or could it be that some records show off a problem with my rig more than others. I hope it hasnt just started to be a thing thats just in my head. I think my next step is to take the Coltrane over to my fathers direct drive technics and see if the pitch continues to sway or not.
I would appreciate any input on the situation. Thanks
Darren
On the first track of John Coltrane Quartet Ballads, I noticed that the ending note on the the first track tended to sway like an old VHS tape compared to the solid pitch of the CD version.
a first pressing of Dark side of the moon compared to my anniversary CD copy resulted in no significant changes in pitch that I could hear.
I guess what Im trying to get at is could that be a issue with the speed of the pressing itself, or could it be that some records show off a problem with my rig more than others. I hope it hasnt just started to be a thing thats just in my head. I think my next step is to take the Coltrane over to my fathers direct drive technics and see if the pitch continues to sway or not.
I would appreciate any input on the situation. Thanks
Darren