New Teres Direct Drive Motor Available as Option

Dgarretson - As Doug points out:

"According to emails from Chris, the performance jump vs. belt drive is inversely proportional to the weight of the platter. Lighter platters have less rotational inertia, so they benefit most."

Presuming this holds true, in terms of yielding improvement, the lighter platter would to a higher degree - so this may be the more bang for the buck solution. However, in terms of overall sonics there is enough difference between say a 255 and a 320, apart from the drive system, that the latter easily bests the former by a pretty wide margin - at least to my ears. The inertia of the larger platter coupled with superior isolation provided by Stillpoint dampers make significant contributions to speed stability and lower noise. When I upgraded from a 255 to a 320 I definitely expected improvements, but the 320 significantly exceeded my expectations. I would be quite surprised if a 255 with Verus could exceed a 320 with the Reference motor.

Over time, I've found my skepticism about Teres improvements consistently disappointed, and Chris' assessments to be quite accurate. Of course I'll wait to hear the Verus and judge for myself, but I have no reason to doubt that it will be an improvement commensurate with the upgrade price. We'll see - I hope the Verus starts shipping soon.

Tim

I got mine today. Initial comments here:

http://www.audioasylum.com/audio/vinyl/messages/67/675079.html

Bill

Pauly, Your stylus drag experiment is interesting...
Physics dictate that the uneven forces from stylus drag will modulate the platters speed. What can be debated is if the effect is large enough to be audible. Our ears are remarkably sensitive to errors in the time domain. Far more so than would seem logical and far more than most would expect.

Contrary to popular thinking platter mass only changes how stylus drag affects speed but cannot eliminate it. A massive platter will reduce the magnitude of the variation but extends it over a longer period of time. A light platter will conversely allow a larger speed variation but it recovers more rapidly. Most, but not all, prefer the shallower variations from a heavy platter but it is a compromise, not a fix.

The Verus motor does show greater improvement (compared to our belt drive) when coupled with a light platter. But there is no evidence that using a heavy platter with a Verus motor is detrimental. We have used the Verus motor with platters up to 70 pounds and as with our belt drive motors have consistently preferred the heavier platters. What we have found is that with the Verus motor platter mass seems to be less important. For example we recently did some comparisons between a 14 pound solid acrylic platter and a 27 pound lead/acrylic platter. With the Verus motor the difference between the platters was about half of the difference heard with a belt drive Signature motor.

So does the Verus motor with a light platter surpass our heaviest platter with a belt? I have not done that comparison but suspect that the answer would be no. But there is much more to the story than mass. The materials used in our 360 platter (brass and cocobolo) sound a lot better than acrylic.

Chris

Very interesting discussion. I look forward to receiving mine in a month or so :-)!

It's generally accepted that a constant, steady platter speed will produce the most accurate reproduction. Above, Chris stated that a high mass platter will produce speed variances of low magnitude and long duration, and that light platters will produce speed variances of high magnitude and short duration.

A main goal of TT design is steady platter rotation, but could TT designers be barking up the wrong tree? Shouldn't we consider the speed variances of the cutting lathe and try to produce a TT whose platter mass, motor power, and stylus drag combine to approximate the speed variances of the cutting lathe? If the cutting lathe's platter slows down and recovers due to a heavy modulation, it might not sound right when replayed in your living room if your TT's platter also doesn't slow down and recover at the same rate. Is it possible that rock solid speed stability in TTs is actually a bad thing?