New Teres Direct Drive Motor Available as Option

Dan_ed,

Somewhere in this thread it's reported that in testing, Verus rim drive produced the greatest improvement in combination with the lightest Teres platter. It would seem that with rim drive (as with idler drive), high platter mass might actually impede speed stability (probably at the point where the motor has insufficient torque to meet the higher rotational force associated a high-mass platter.) But I suppose that high-mass platters are also better at resonance control. So there is likely a trade-off with how light one would want to go without resorting to fancy TT mats and other approaches to resonance control.

Since with rim drive as with idler-drive, speed stability is entirely determined by the motor, it would be interesting to know whether the 1800 RPM motor of the Lenco offers an inherent advantage. I assume that with the Verus, the drive pulley is pressed onto the spindle of a low speed motor. Perhaps the best rim-drive design would be a high-speed motor with multiple wheels and a step-down transmission. This might also improve isolation of motor noise.

Finally, issues of force and compliance surrounding stylus drag can't be too much different than issues regarding VTF. This is handled easily in a TT arm by counterweights & gravity.

Dgarretson,

That is along the lines of the point I was attempting to make. A given motor speed and torque in the rim drive system may have a range of platter weight that works best with that given motor. Then again, it could be testament to how well these heavier platters with mylar belts actually work. ;)

I think the extra gears of a reduction system are going to introduce more noise. IME, gears don't mesh silently and there will still be slop between the teeth. That is why the Lenco rubber-tired idler wheel can work well when everything is in good shape.

"Finally, issues of force and compliance surrounding stylus drag can't be too much different than issues regarding VTF. This is handled easily in a TT arm by counterweights & gravity."

I would agree with you on how easily this is handled except that so many tables/arms don't. Perhaps that attributes to the rising price structure of many 'table/arm lines?

"A given motor speed and torque in the rim drive system may have a range of platter weight that works best with that given motor. Then again, it could be testament to how well these heavier platters with mylar belts actually work."

I'd like to hear an opinion from Teres on whether the Verus with a light Teres platter surpasses their heaviest platter with mylar tape drive.

Me, too. :) But I'd also like to hear that from others as well.

I hope this is ok to post here. I just found this posting by Mark Kelly over on AA related to this topic.

"The idler drive mechanism has only a few percent of the speed variability inherent in belt drive (due to the lossy transmission eg belt creep).

Most idlers make up for this by using motors which can't hold constant speed against variations in platter drag (like the stylus traversing the record). Anyone who says their stock Garrard holds constant speed simply isn't measuring it properly.

As against this, the short term speed stability of an idler is excellent due to the almost lossless transmission from a motor with a high amount of flywheel effect. Most people assume this is due to the motor having lots of torque but that's not the case.

The other problem is noise - an idler definitely transmits more noise than a belt and they can create extra noise all of their own if the bearings aren't perfect.

Altogether its a toss-up.

Mark Kelly"