VPI motor - upgrade to 300 rpm?

What your problem may be, is the Drive Belt? When was the last time it was changed?

The SAMA Motor shouldn't be changing, or fluctuating speed, and the SDS should be providing stable voltage-frequency to the Motor.

But, if your SAMA is using the newer, "stepped drive pulley", that one can adjust speed at the pulley in very small increments by which little groove the Belt is placed on, it is possible that an old, or worn belt is wandering on the Pulley?

Those ridges on the pulley are very small. I'd try this forst before resorting to Motor swap-outs. Mark

Not sure yet if my first response will be posted, but besides the possible issue with the Belt changing places on the Pulley, another cause could be the possibility of your SAMA not remaining stationary?

I'm finding that out myself with a recent SAMA installation, that the stock rubber SAMA feet seem to be inadequate. My SAMA I note is beginning to pull towards the Platter, that I'm noting inconsistency of Belt Tension due to this "pull", I'm seeing the Rubber feet bend-lean under this pressure, and am in the process of retro-fitting my SAMA with a set of Herbies Tenderfeet.

They are a few mm taller, but a wider foot, at 1.1" x 1.1".

Other devices out there could be used. I think the important thing, will be providing a rock solid anchoring of the SAMA to whatever Shelf-Rack you use. Mark

Yes, true, the newer SAMA from what I can see as well, is basically empty. Nothing inside, but a Foam Sheet isolating-seperating the bottom of Motor Case from the Run Capacitor.

But, the 600rpm Motor is not inheritly bad as far as speed stability goes, and if working properly, is not prone to the large degree of speed variation that you are appearing to notice.

So, with that said, yes, the Motor could be at fault, and I imagine if it is doable, one could then possibly opt for either the 300rpm Motor, or otherwise, a new 600rpm Motor should do the trick.

It will be VPI that may have to answer your questions, if the 300rpm Motor will be a simple swap, or will one have to modify the SAMA Case in order for it to fit? We can assume that a different Pulley would indeed be needed. The question is, does VPI have the correct Pulley that will work with a SAMA. Meaning, will it be long enough to protrude far enough, and up through your Plinth to reach alignment with Platter? That is an unknown to me?

Having to glue the pulley, I then assume you once had either slippage, or wobbling of the Pulley, to require gluing it to the Shaft?

I think we can all agree, that the Base on which your Table, and SAMA rest upon should not be an influence of the Motor's speed stability, that this would be caused by something else? But what?

The only other influence that I can think of, in regards to speed fluctuation, would be the VPI SDS at fault? One would have to test the SDS to find if any fluctuations in voltage and/or line frequency are taking place?
Mark

Please keep in mind, that VPI is on vacation till Jan 11 I believe. Mark

Hello O_holter,
Seems to still have interest, and are persuing the use of the 300rpm Motor.

If it is permissible by the mods, I would like if you could further explain what it is you are not liking with your sound? Is it noise, or vibration from the Motor you're hearing-feeling? Which SAMA is this you have, the newer one, or the older one with round case?

I see you mention PRAT? What other sonic dislikes are you noting? What are you using as a Plinth Suspension? The Pucks, or Springs?

Are you still using the stock Rubber Feet on the Wood Base?

These are two areas, where the chageout to a cone foot for the Wood Base, and using something like Herbies Iso Cups-Balls, or Tenderfeet for a plinth suspension should net you some good, not subtle sonic gains.

As I believe I mentioned earlier in this thread, I too am running a modded HW-19 with newer version SAMA, SDS, 16 lb MK-IV Lead Filled Black Acrylic Platter. My custom HW-19 does not have a seperate Armboard, but uses a custom made solid one piece 1.00" thick Acrylic Plinth secured to the Steel Sub Chassis Plate.

I now use the Herbies Extra Firm Tall Tenderfeet to replace the Sorbo Puck Suspension. I use the short soft Tenderfeet to replace the stock rubber feet on the SAMA, and use Brass Audiopoint Cone Feet to replace the stock Rubber Feet on the Wood Base.

I cannot imagine my Table being any quieter than what it currently is, it is totally dead quiet in operation.

Dislike of sound can maybe be sourced to other components in your chain? Your sound will only sound as good as its weakest link. Mark