New Aluminum Platter from VPI

Johnbrown, What custom pulley are you talking about? Having experimented at length with custom pulleys, I can report that some pulley designs add more problems than they solve. And there is nothing wrong with the Hurst motor-- unless you are dismissive of AC motors altogether.

BTW, a TTweights copper or copper/carbon fiber mat is an excellent alternative to VPI's expensive platter options.

Hi Bob, I'll add that thread drive and tape drive are both somewhat tweaky-- requiring correct selection of threads, knotting & splicing techniques, and precise tensioning. They are not plug-and-play like the soft rubber belt. My guess is that HW stays with the rubber belt because of its non-critical set-up and ease of use with a large number of casual TT owners. These are not unimportant considerations. Nonetheless, anyone who has not tried thread or does not have a speed controller is wasting his money with a platter upgrade.

Johnbrown, That is a good experiment, and one that may be worth continuing with a DC motor or other AC motors to compare to Hurst. The question remains as to whether there are other AC motors that behave any better than Hurst w/r to cogging. Another possibility is that my two-phase Kelly drive controller is doing a better job of reducing AC motor vibration than a single-phase SDS. However, with thread drive I've noticed that the tension needs to be relaxed a bit more than one might expect in order to optimize audible speed stability. I'm inclined to conclude that an AC motor needs a small amount of compliance in the belt-- certainly not as much sloppiness as a stock VPI rubber belt, but probably more than your mylar tape.

Perhaps HW was led to combine compliant belts with rim drive in order to deal with AC cogging. One would have thought(on paper at least), that a direct-coupled DC motor like Teres Verus would be a better choice for rim drive. But Teres has its own cross to bear: the O-ring on that small drive wheel needs to be perfectly round, which may be more easily said than done.

BTW, by adding a spring-loaded tensioning capstan to your tape drive, you might be able to vary compliance.

Dave