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Well Tempered reference motor vibration excessive?

I have recently purchased a used Well Tempered reference turntable. I have owned the clearaudio reference in the pastand a sme 10. If you hold the clearaudio motor in your hand there is only a mild vibration palpable, this is shown to be the case when listened to with a stethoscope.

The well tempered motor is significantly noisier via stethoscope and the held in hand vibration is quite horrendous considering it is a reference turntable.The vibrations are getting transmitted up my forearm. I wonder if this is the cause of some of the inadequacies i hear regarding this turntable from various reviewers. Apparently compared to top notch turntables there is a slight lack of detail and the bass could be better etc etc.

I would be interested to know if anyone has tried a dc motorand whether the motor vibration I have is consistent with other users.The motor does run true to 33.3 so I have no reason to belive it is faulty. I have opened the unit and serviced it and ensured the locking screws are tight.

Utilising the two subjective (though not in accurate) methods of measurement for motor vibration, i was able to bring the perceived vibrations right down with some simple tweaks. If you were to use a scale of 1 to 10, one being minimum vibration. Then the combination of the below described tweaks have reduced the vibration rating from 10 to about 3. That is it is with concentration that the vibrations are palpable when the motor is held in the hand.

By placing elastic bands around the rim of the bottom lead weight and the rim of the top circular shelf, as well as around the central section helped reduce the vibration by about 25% of the total.

Unscrewing each of the rubber feet a few turns under the motor so that they didnot touch the lead base by a further 20%.

Replacing the copper mains lead with a silver plated copper coaxial cable, with doulble outer shielding braids (bought from RS components), and using a seperate coaxial for live and neutral, by about another 50%.

Surprizingly utilising an ac regenerator (ac 240v to 12v dc to 110v pure ac .01% accurate)did not make much of a difference to the vibration subjectively perceived, either with or without the coaxial cable.!!!!! When you consider the coaxial cable cost no more than $20, and the ac regenerator over $250, that is a remarkable finding.

However, I have not been in a position as yet to get to do the audible changes to the music made by these tweaks. I will post these forward if anyone is interested in due course.

I already have plans to rewire the arm, utilise bullet phono plugs, changing the silicon fluid viscosity etc, to get it to perform better than my sme10 (heavily modified, possibly sme 30 rival now and the clearaudio ref).

Dr Luke
audiojoy4
audiojoy4 OP
98 posts
 
Hi Honest thanx for your reply.

I am not certain that I have in fact isolated the motor from its casing. The elastic bands I believe are absorbing the energy transmitted, not isolating it to the inner motor. The coaxial is stiffer as you say. However numerous repeated tests using active preamps, dacs transports, power amps etc etc, have demonstrated that even if the interconnect/power cable has <5% coverage of a 2 meter interconnect there is an audible differnece quite dramatic if you use a sensitive 104db tool as the avantgarde duo loudspeakers. Therefore I can only conclude that this some form of electromagnetic effect as the braids are not earthed. Nonetheless you have thrown another light on the situation. I will respond on this thread as soon as I have completed the actual hearing tests.

Luke
honest1
586 posts
 
Could be. If the rubber bands are wedging in between the motor and its case, they could be clamping the motor, coupling it more closely to the case, thereby adding mass and making it harder for the vibrations to create movement. My understanding is that the Well Tempered motor is housed in a case separate from the table, sitting directly on the equipment shelf (not touching the rest of the table except through the belt). Is this correct? I would not disagree that shielding interconnect cables could make a difference in the sound of amplifiers and transports, and even the power cable too, because the electricity eventually becomes the signal, and any noise will get amplified. It may even make a difference to the sound of a turntable motor. But I would be surprised if it could effect such a dramatic reduction in felt vibration (your sense of hearing is much more sensitive than your sense of touch). The amount of elecdtrical noise imposed on the lines is very small compared to the electricity used by the motor, and I don't think it would cause the amount of vibration described. This is why the power regenerator did not help. The electrical effects of the shielding and power regenerator may have a sonic effect, though.
jimbo3
304 posts
 
I, too, wasn't impressed with the WT motor on my Classic model. Switched it out with an OL DC motor. Seems to be quite an improvement- quieter, better bass, more detail.

Regards
Jim
audiojoy4 OP
98 posts
 
Honest1
the well tempered motor is housed in a seperate casing, which does not fully encase the motor. at no point do the elastic bands touch the actual motor itself, they only touch the casing. The top of the casing is about half a cm deep, it is a cylinder about 5cm in diameter, with the motor spindle sticking out from the middle of it. The whole motor/case unit is then placed in a hole in the chasis of the turntable, so it is not in direct contact with the chasis, and sits on a seperate plinth beneath it decoupled from the main chasis.

Now each time I add another elastic band around the circumfrence of the cylinder the more and more the vibration is palpably and audibly diminished, albeit subjectively. Three seems to be the optimum number.

Back to the electromechanical argument i do remember doing a similar cable modification on my previous clearaudio motor. When I look back i remember I managed to get the same amazing effect with softer lighter coaxial cable nowhere near as stiff as the one I use today. Please also note that about the first ten cms or so from the motor is the original wiring before i actually connect it to my more complex cable.

Further proof that an electrical event is at play here is that during my set up with the ac dc ac converter, although the changes were minimal, there was I believe and I know once again it is an insensitive method, a further reduction in vibration when i used the same coaxial cable as power supply to the ac/dc converter, this unit then of course goes through the dc/ac converter before being attached to the motor cable itself. So I do have evidence that still possibly supports my theory. However I have no doubt that your mechanical theory also is contributing.

I hope this enlightens you further.

regards Luke
honest1
586 posts
 
Very interesting. Keep us posted with the results of your listening tests!
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