New Aluminum Platter from VPI

"Another possibility is that my two-phase Kelly drive controller is doing a better job" - it had better be!

Try tweaking the third harmonic control whilst running the platter, you should be able to find a minimum in the cogging torque transmitted.

"I'm inclined to conclude that an AC motor needs a small amount of compliance in the belt"

But how much? How does one calculate the optimal value?

I have just taken possession of some new belts which are far , far less compliant than standard Mylar tape. I am combining them with those "crappy coggy Hurst motors". I think you will be interested in the result. It will hopefully be at RMAF in October.

Mark Kelly

I've come to the same conclusion about the thread tension. Too tight and it doesn't sound right. It needs to be just tight enough to grip, but still loose enough for the weight and mass of the platter to do its speed stability thing without being hampered by the string.

I'm also using a twisted silk thread, which seems to be able to give me that little extra grip while still remaining a little loose. The thickness of the thread also seems to make a difference, with a thicker one sounding better to me. But it can't be too thinck or the knot size becomes a problem.

I'm using thread from here and recommend size 2 or 3 (in whatever color your heart desires): http://www.artbeads.com/stringing-materials-griffin-silk-bead-cord.html

I'm also using Mark's controller on my Hurst 600RPM motor. When it's dialed in I almost can't feel it running while holding it in my hand. Very quiet, but it does take a bit of tweaking to get to that setting. It also does vary with the clock setting a bit so I'm prone to finding the right thread and sticking with it rather than swapping them out and resetting the clock and "quietness" each time.

Bob

Interesting to see that the Super Platter is no longer listed under the accessory section on the VPI web site?????????

If I have anything to say about it, we'll get to see and hear an esoteric solution from Mark in our Galibier room at RMAF this year.

We just completed manufacture of 5 of the 7 machined parts in order to begin prototyping.

Y'all know me to have been in the DC motor camp for quite some time, but not as an absolute statement about architectures. Rather, it's because I haven't heard anything to convince me to switch.

Mark is just the fellow to convince me (and others?). Stay tuned ...

Cheers,
Thom @ Galibier

If you check Harry's website, the Superplatter is no longer listed - the aluminum platter will be shipped with the Superscoutmaster.