Is Direct Drive Really Better?

Thanks. I knew it was a tough question.

Dan,

Do you remember the color of the belt on the 320 and 280? That isn't as silly a question as it sounds.

While I don't believe a BD Teres will ever match a well implemented DD Teres (especially when the DD costs twice the price) it is true that torque delivery on a 320 is significantly affected by the choice of belts. I've probably tried more belts on a 320 than even CB has had time to play with. I'm curious which one he was using.

Doug

P.S. Two or three years ago I posted a thread describing belt experiments on our original Teres 265. I commented that the increased torque coupling from 1/2 mylar vs. silk thread had no real downside because the Teres motor was so quiet that motor vibration was a non-issue.
Eldartford made a wise observation: if the motor's so quiet why not make a direct drive? It looks like we're just about there, and that he was right.

I'm pretty sure it was a clear belt that was used on both the 280 and 320.

I also remember him using a clear belt.

That's the 2 mil mylar belt, which is a close second best of all the ones I've tried.

Dan may remember seeing a holographic silver belt on our table. It out-torques the 2 mil clear one by a small but audible margin, not because of the color (presumably) but because it's about 10% thicker. This seems to be the optimum material for this application. When I went up to 3 mil mylar the sound started going fat and soft again. That belt was too stiff to make the sharp turn around the motor capstan without slipping.

At any rate, that clear belt is quite good. This makes your report on the superiority of the DD table even more convincing.