Four things to look at:
1. Early 600 rpm SAMA came with a flywheel. It looks like a large stainless steel washer that slides over the motor spindle. VPI stopped using it at some point because it wobbles causing speed variations, flutter and rumble. If your SAMA has one ditch it.
2. Worn belts will cause speed fluctuations. Don't get a third party belt. Only a few dollars more to get the VPI belt.
3. Dirty or dry platter bearing will cause speed fluctuations. Clean it out with alcohol and q tips and oil it sparingly with a high quality oil. I like sewing machine oil.
4. I've had a couple generations of the VPI speed controllers (SDS) and was never pleased with any of them. I now use a Phoenix Engineering Eagle and Roadrunner. They keep speed dead on to within about .004. Unfortunately Phoenix recently went out of business but if you can find the pair used for a decent price they are great.
1. Early 600 rpm SAMA came with a flywheel. It looks like a large stainless steel washer that slides over the motor spindle. VPI stopped using it at some point because it wobbles causing speed variations, flutter and rumble. If your SAMA has one ditch it.
2. Worn belts will cause speed fluctuations. Don't get a third party belt. Only a few dollars more to get the VPI belt.
3. Dirty or dry platter bearing will cause speed fluctuations. Clean it out with alcohol and q tips and oil it sparingly with a high quality oil. I like sewing machine oil.
4. I've had a couple generations of the VPI speed controllers (SDS) and was never pleased with any of them. I now use a Phoenix Engineering Eagle and Roadrunner. They keep speed dead on to within about .004. Unfortunately Phoenix recently went out of business but if you can find the pair used for a decent price they are great.