Kudos to speed controllers

What Larryi says about why motor controllers make such a readily apparent difference is true, but the Walker may do the same thing as the Basis one, i.e., supply two sine waves in quadrature (90 degrees) apart in phase. I own a Walker and love it, but in truth I am not sure about whether it supplies two sine waves. I have been meaning to take mine apart to have a look. Regardless, it makes a huge difference. With a little web searching and elbow grease, one could build one's own two-phase motor controller for quite a bit less than $3500, however.

The Walker motor controller as supplied does not generate a “quadrature AC” source. The purpose of a “Quadrature AC” power supply in a synchronous AC motor application is to eliminate the phase delay capacitor. The walker motor controller is very good but it does not eliminate the capacitor used inside the AC motor. Apparently the reports I've heard from friends have stated that the Walker motor controller is able to drive the motor smoother than the VPI SDS with less vibration and noise transferred into the platter. I’ve listen to the VPI SDS drive a VPI table and it performed well. I've also worked with a few systems that have Walker motor controllers in them and they work very well. I’ve never directly compared the SDS against the Walker motor controller.

There is really no way to demo the Basis Syncro-Wave Power Supply with your current motor because it requires the motor to be sent to Basis to be modified. Therefore, one would need the entire drive system (controller and motor) to witness the results. Unfortunately, you are not going to find many, if any, dealers with Snycro-Wave drive systems available to send out for demo. It’s really unfortunate because the drive system really pushes the Basis tables even further forward in performance.

My personal turntable is using a version of the Synchrotron AC-1 that I built which is similar to the Basis Syncro-Wave Power Supply. Both of these units require the removal of the phase delay capacitor in AC motors that run off the wall power. The result is a quieter motor with significantly reduced vibration. This is extremely apparent with the 45RPM setting because that particular speed is much more difficult for the SDS or Walker controllers to keep vibration down. Anyone with a Walker or SDS can test my observation in real time by feeling the motor in 33RPM vs. 45RPM mode. The synchronous AC power supplies are so smooth that it's difficult to tell (feel) that the motor is on without seeing the platter rotating in both speed settings.

All that being said, the use of a motor controller (Walker or SDS) on an ac motor is great for adjusting precise speed. If I had to choose between the SDS and the Walker, I’d pick the Walker even though it’s not as nice looking. I lean significantly more toward substance, operation, and function than aesthetics…

For those with Basis turntables (Except the Debut) without speed controllers, you can still get the speed set precisely by adjusting the distance of the motor pod from the platter. My estimate would be that you could have as much as a .2% range of adjustment using extreme distance changes. For the most part, the basis tables using the proper belt are very close, if not on speed, to being correct to begin with so the extreme adjustments are most unlikely.

Hope this helps,
Dre

The Walker motor controller as supplied does not generate a “quadrature AC” source. The purpose of a “Quadrature AC” power supply in a synchronous AC motor application is to eliminate the phase delay capacitor. The walker motor controller is very good but it does not eliminate the capacitor used inside the AC motor. Apparently the reports I've heard from friends have stated that the Walker motor controller is able to drive the motor smoother than the VPI SDS with less vibration and noise transferred into the platter. I’ve listen to the VPI SDS drive a VPI table and it performed well. I've also worked with a few systems that have Walker motor controllers in them and they work very well. I’ve never directly compared the SDS against the Walker motor controller.

There is really no way to demo the Basis Syncro-Wave Power Supply with your current motor because it requires the motor to be sent to Basis to be modified. Therefore, one would need the entire drive system (controller and motor) to witness the results. Unfortunately, you are not going to find many, if any, dealers with Snycro-Wave drive systems available to send out for demo. It’s really unfortunate because the drive system really pushes the Basis tables even further forward in performance.

My personal turntable is using a version of the Synchrotron AC-1 that I built which is similar to the Basis Syncro-Wave Power Supply. Both of these units require the removal of the phase delay capacitor in AC motors that run off the wall power. The result is a quieter motor with significantly reduced vibration. This is extremely apparent with the 45RPM setting because that particular speed is much more difficult for the SDS or Walker controllers to keep vibration down. Anyone with a Walker or SDS can test my observation in real time by feeling the motor in 33RPM vs. 45RPM mode. The synchronous AC power supplies are so smooth that it's difficult to tell (feel) that the motor is on without seeing the platter rotating in both speed settings.

All that being said, the use of a motor controller (Walker or SDS) on an ac motor is great for adjusting precise speed. If I had to choose between the SDS and the Walker, I’d pick the Walker even though it’s not as nice looking. I lean significantly more toward substance, operation, and function than aesthetics…

For those with Basis turntables (Except the Debut) without speed controllers, you can still get the speed set precisely by adjusting the distance of the motor pod from the platter. My estimate would be that you could have as much as a .2% range of adjustment using extreme distance changes. For the most part, the basis tables using the proper belt are very close, if not on speed, to being correct to begin with so the extreme adjustments are most unlikely.

Hope this helps,
Dre

I'd like to take exception to the statement that the Synchrotron AC-1 is similar to the Basis unit. Perhaps I should say "was", the AC-1 kit has been withdrawn permanently.

The AC-1 was an original design which used a different circuit topology to achieve different results. It offered a couple of features which are not offerred by any available controller (adjustable phase angle, adjustable harmonic tuning).

The similarlity with the Basis is simply that both are two phase controllers, but that's a bare minimum for any modern controller in my opinion.


Mark Kelly

Mark,

"The similarlity with the Basis is simply that both are two phase controllers"

This is exactly what my post was about.

I'm fully aware of the unique features of the AC-1 but that was not the purpose of my post. It was simply to point out the fundamental difference between two-phase units and those like VPI and Walker that are not two phase units.

I also have no idea how the Basis unit is adjusted to the motor when it is sent in to be modified and I simply won't comment on an aspect of the design that I'm not familiar with.

As you had stated, you pulled the kit permanently. It didn't make any sense to tout the unique aspects of the AC-1 when the readers of the post couldn't have access to it. It's kind of like a "look at what I have but you can't have it" comment. Personally, for me to say something along those lines would have been in very poor taste.

Although we haven't conversed via e-mail since I sent you comments of the results of the build, I hope you are working on something to offer in the future for those that didn't get the chance to enjoy your work.

Dre