High friction bearing for low mass table- sounds nuts to me.

Posted by jsm (A) on January 28, 2008 at 18:04:19

In Reply to: RE: Ayre DPS turntable - Comments by Hansen/Silberman posted by berlinta on January 28, 2008 at 04:56:45:

If one increases the friction of the TT bearing and then uses a high torque bearing to overcome it and then argues this has reduced the effect of of stylus drag, this is completely wrong! All that matters is the drag force of the stylus compared to the residual torque of the motor- the amount of torque left over after it has overcome the bearing friction. Suppose the bearing friction force is ony very slightly less than the high-torque motor's ability to overcome it. Then just the small addition of drag force introduced by the stylus could bring the table to a halt. If you say this is extreme, you are missing the point. The effect is the same. We are only discussing the magnitude. Now if the bearing friction depended on the drag force of the stylus in some kind of feedback way, that is a different story.

Think how much better it would be to have an extremely low friction bearing and high torque motor if ALL you are worried about is stylus drag. Then the motor wouldn't be affected in the slightest by the drag force of the stylus because of its overwhelming torque. Using up a lot of the motor's torque in overcoming bearing friction sounds like a mistake to me, as it makes stylus drag forces all that more important. Think about it. All that counts is the drag force of the stylus compared to the torque of the motor. The bearing friction simply reduces the effective torque of the motor, uses some of it up, and makes things worse. The bearing friction only operates in ONE direction. It wants to slow down the table. It can't be a stabilizer. Any additional drag like that of the stylus just adds to the problem. A heavy table resists either speeding up or slowing down because of its high moment of inertia. That is very different.

Joe

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Follow Ups Full Thread

Topic - Ayre DPS turntable - Comments by Hansen/Silberman - restock 21:24:58 01/27/08 (12)

RE: Ayre DPS turntable - Comments by Hansen/Silberman - Davy-pie 13:32:39 01/29/08 (0)

RE: Ayre DPS turntable - Comments by Hansen/Silberman - restock 13:48:29 02/01/08 (0)

A clarification from Hansen - Charles Hansen 10:21:43 01/28/08 (4)

Thank you for the thorough clarification! - restock 12:00:21 01/28/08 (2)

RE: could not find your contact information or and email address for Ayre - Charles Hansen 20:27:19 01/28/08 (1)

RE: could not find your contact information or and email address for Ayre - ejlif 21:19:42 01/28/08 (0)

RE: could not find your contact information or and email address for Ayre - Charles Hansen 19:43:14 01/29/08 (0)

A clarification, indeed! Which is just what is needed to... - Neil49 10:43:41 01/28/08 (0)

RE: Ayre DPS turntable - Comments by Hansen/Silberman - berlinta 04:56:45 01/28/08 (3)

High friction bearing for low mass table- sounds nuts to me. - jsm 18:04:19 01/28/08 (1)

RE: High friction bearing for low mass table- sounds nuts to me. - berlinta 02:28:07 01/29/08 (0)

RE: Ayre DPS turntable - Comments by Hansen/Silberman - restock 08:54:05 01/28/08 (0)

RE: Ayre DPS turntable - Comments by Hansen/Silberman - DevilDawgMom 21:37:42 01/27/08 (1)

Thanks!! - restock 21:52:51 01/27/08 (0)

Follow Ups

High friction bearing for low mass table- sounds nuts to me. - jsm 18:04:19 01/28/08 (1)

RE: High friction bearing for low mass table- sounds nuts to me. - berlinta 02:28:07 01/29/08 (0)

High friction bearing for low mass table- sounds nuts to me.

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