VPI SDS help

I bought a VPI SDS here on Audiogon for my townshend rock 7 turntable. According to my research The rock 7 is ac motor 110 volt.

I installed the SDS with the TT but the TT motor is spinning very slowly at the 33rpm setting. I changed the default sds voltage from 72 to 115 but it's still slow and increasing the frequency from 60 to 65 did not get it working right either.

Am I doing something wrong or does the SDS not work with this TT
No way to know if the SDS is broken, or it just does not work with your TT.
Call or email VPI and see if they have had experience with this combination. I am currently using an SDS on a non VPI table; a look at members systems will show that some others are also. But each table has its own characteristics.
You may need patience trying to reach VPI - they often don't answer the phones or respond to e-mail for days at a time. There is no excuse given the size of their customer and dealer base.
I emailed VPI based on that good suggestion here.

VPI responded:

Check the capacitor on your motor, if it is less than .68 microfarads you need to change it for a .68.  Less than that value and the SDS looks at it like it is a short.

MY Question now is how easy is it to change capacitors on a turntable motor?


I should have thought of that, the Classic has to have a capacitor changed to prevent a loud pop or to use the SDS. On the Classic it was very easy, I have never has a Townsend so don't know. I suspect it is not too hard. On the Classic the cap is in the AC line attached with wire nuts [ wire nuts ARE NOT those members given to buying $2000 ICs and $3500 PCs, but I digress]. Try to take the bottom cover [if it has one] off and see if you can see a cap. Unplugged of course.
Are you SURE? ... about those wire nuts?
I have inspected wire nuts in my electrical equipment with a microscpe and they certainly look EXACTLY like those 'other' wire nuts that buy $2000 ICs and $3500 PCs.
(little tiny guys with cables in hands waving them excitedly over thier heads..)
I have never heard of needing to open the motor of the turntable and replace a part to be able to use an external motor controller. I am going to contact Townshend regarding the ease and viability of doing so?
You have to do this in order to use the Classic with the SDS, a really stunning design failure on the part of VPI in my opinion. It is not in the motor itself but wired into the AC line. The Classic is also prone to making a loud pop when turned on requiring the same capacitor to be changed. They did not inform the dealers of this problem, I had to email them to find out about it.
I had this exact problem with my Rega 25 and VPI SDS. I found that if I gently help the turntable platter gain speed (on startup) by gently turning the platter by hand--giving it a gentle shove--the SDS will drive the Rega 25. I guess the SDS doesn't have the power to overcome the inertia of the platter at startup; but once the platter is spinning, the SDS drives it without further problem. Without doing this procedure my Rega would sometimes play at a speed below 33.

thanks for the suggestion. Once the SDS began to drive it, did you find that SDS maintained accurate speed for the TT at both 33 and 45rpm?

My SDS will work with my Basis 2001 at 33 but the table will not rotate at all when I switch to 45. I get the correct speed by switching the belt. Speed is accurate at both 33 and 45.

Regarding your question, once I help the SDS get my platter spinning it maintains its speed perfectly at 33 rpm. I don't use 45 rpm. I will add that I have been very happy with the improvement in sound that I get with my SDS.
I had the same problem using the SDS with my Rockport Capella II. I borrowed a 230V output SDS (as I was in Hong Kong) to power the Capella, and while it worked fine for 33, the platter would slow down and stop when I switched to 45 with the SDS. The same thing happened to the PS Audio Powerplant 300. I wrote to Walker asking whether their controller could drive the Capella, and their reply was negative, stating the Capella’s motor was too big. Apparently there are turntables which the SDS is not compatible with!
I had no luck with the "gentle shove" method with a 45rpm record. My turntable dealer is checking with the manufacturer if the capacitor can be readily changed on the motor to .68 as suggested by VPI
An old thread, but I wondered if Radioheadokplayer ever got this combo to work? Or anyone else try to pair an SDS with the Rock?
I use the SDS with my clear audio master solution. Heavy platter that needs a little help to get spinning compared running motor direct to ac line.

Once spinning it is very stable and also easily spins up to 45 when switching the SDS. I felt the improvement was noticeable.