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Why three motors?


Can someone enlighten me on the wisdom of having a three motor turntable like the TW Acustic with only ONE side of the belt touching the platter?

Here is an example.

I just don't get it...
hiho
mesael
57 posts
 
Ok, my understanding in layman term, the belt will somehow suck the life out of the music. So the least the contact of the belt with the platter, the better. I owned Raven AC with one motor and in the process of ordering the 2nd motor.I also believed the two motor setup is more balance.

Regarding the Black Knight, the position of the motors have better grip with the belt. Who knows, Mr Thomas might come up with another set of motors on the other side of the plint in the future.
audioquest4life
775 posts
 
I have a Transrotor Apollon with three motors but the arrangement is different. The belts actually fit on a grooved slot on each motor that corresponds with a grooved slot on the magnetic bearing assembly on the bottom of the platter. My platter is really heavy, 80mm thick polished aluminum and three motors helps in regards to maintaining speed accuracy, timing and just the sheer grunt to move such a heavy platter.

Onhwy61 said it best: "Whatever variations, irregularities, etc. in one motor are averaged or even canceled out by the other motors."

It should lead to better speed stability, both long and short term. Never had any noise or vibration issues from the three motors. All I know is that with one belt, the platter spins up to speed a little longer with a nudge, but with all three belts, the platter is under absolute control of the belt grips and they belts take control and you KNOW there is more torque grabbing the platter.

I think it would be the difference between a kid spinning a "merry go round" versus Hulk Hogan, Mr. T and The Hulk, yeah that is it.

Anyway, voiding any disparaging comments from the technical aspects concerning pros and cons of having three motors; the three motors I have work great for me and the sound is incredible.

Thats my story and I am sticking to it.
Ciao,
Audioquest4life
hiho OP
451 posts
 
T_bone: "Any idea what the tonearm with the wooden armpipe is?"

It's a German tonearm made of ebony.
_______________________________

One of the explanations about the belt arrangement I read is that it simulates an idler wheel with low contact area. If that's the design intention I found that unconvincing. The three motor set up with such belt arrangement has been discontinued by the manufacturer so I have to assume the designer no longer endorse such approach.

Here's a lively discussion about the design.

Again, I found the belt arrangement to be half-baked until someone can explain it to me otherwise.

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hiho OP
451 posts
 

Various three motor turntables in different belt arrangement, either single belt or triple belts and all of them have the platter touching THREE sides of the belts.

Audionote

Transrotor

Clearaudio

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dertonarm
1,042 posts
 
Hi Hiho, well - thanks for posting those three 3-motor-drive contenders. They all share the very same set-up - as far as geometry goes. All using a 3-side-symmetrical approach. Somehow logic and going along with the common sense of mechanics in providing a force-vector free bearing in the horizontal plane. I guess we still haven't found the true idea behind the Raven's 3-motor-drive.
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