Get Stoned

I agree, its hard to imagine this would make a significan difference, but I firmly believe everyone's system has strengths and weaknesses and improvemnts for some might not be for others and vice-versa.

That being said, as a former VPI Aries 3 and SDS owner, maybe the SDS 'acts' like an amp. Minimize the vibrational aspects to the cabinet of the SDS and it could conceivably improve it's ability at volatge control and thus speed control to the motor. Better speed control equals better sound.

What would be interesting is if someone would us the Feikert iphone speed app or another measuring device and measure the speed accuracy of the SDS with and without the terrastones. That would definitely confirm what Stringreen could be hearing.

I do own a VPI classic 1 but, not the SDS controller. I am powering my classic 1 with the purepower 1050 AC regenerator. The purepower unit does output a true 60hz/120v feed. I haven't detected any flaw in speed stability so far. If it is off speed I can't detect it audibly. I would like to try the SDS to see if it would make an improvement.

The reason I responded to this thread is beacuse I have just ordered some terrastone products and thought I would share what information I know about the material. According to Dan @ edensound, Terrastone material is a very dense isolation polymer. He said it serves a dual purpose of rejecting outside vibrations as well as damping vibrations originating from the source component. I'm not sure exactly how this is achieved, you would need to ask dan about that.

I tried some of dan's brass bearpaws on my classic one. They did make a very noticeable improvement but, I had some low frequency vibration problems due to the rigid setup. Dan suggested the terrastone because it does a better job of isolation than the brass. I have ordered a custom terrastone platform and a set of terrastone footers for my VPI table. I will post some pictures and my impressions of those products after I integrate them into my system.

I would assume that the terrastone polymer would do a great job of isolating the SDS unit as well. I can't understand how isolating the SDS could improve the sound though, as it is a speed controller and is not directly in the audio signal path. I'm am not saying it doesn't work, I just can't understand how. I guess don't knock it till you try it.

Another thought...

Try this: take the belt off the motor so that the platter won't move, lower the stylus onto the platter, switch on you amp and turn up the volume. Now switch on the motor and you should hear hum.

The hum will come and go as you switch on and off the motor. The hum isn't electrical, it is from the vibration of the motor transmitted through the table and shooting back up to the platter from the cone feet.

Try the above with footers under the SDS and then not. If you hear less hum when the footers are on, then the SDS and Power cable are acting as a vibration sink for the motor.

I think Philb's idea is worth considering, but I suspect that there would not be any differences in speed detected. If the VPI SDS was that supscetible to mechanical energy the product couldn't do what it does so well. I measured my speed using ISpectrum, a software based Oscilloscope, and a 1000 Hz test tone. The speed was rock stable.

I had a theory, but it's a stretch...

All the VPI motors vibrate considerably, if by chance Stringgreen's powercable from the SDS was pulling some of that vibrational energy away from the VPI motor, though the cable, and down though the SDS and footers into a vibrational sink. The net effect would be a motor that is vibrating less. Less vibration would yield a lower noise floor.

Stringgreen, can you post a photo of your setup?