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Turntable Speed

I own a Transrotor "Atlante" turntable. I purchased it about 2 years ago with all the available upgrades (platter and tonearm). This unit was $4500.00 without cartridge. It is a belt driven product with an outboard power supply which lowers the incoming voltage to the 18 volts the motor requires. My problem is turntable speed. My 'table speed is about 34 rpms. I could be more accurate if I had better measuring equipment. Anyway, that's about 2% over the correct speed and you can definitely tell the difference in sound quality between 34 and 33 1/3 rpm!. I was a little upset with this revelation and called my dealer about it. I also talked with the dealer's supplier. I received several reasons from these people as to why the speed was not accurate among which was that my power was "out of tolerance." But when all was said and done, none of the given reasons held water and I am now being advised that really there is nothing that can be done. That there is no defect in the equipment and if the speed problem continues to bother me, I should invest $1700.00 in a Transrotor speed controller. As I think over this, I wonder why platter speed is never mentioned or measured and reported on in the reviews for turntables in the major audio mags. (This could be because there isn't any problem, except for my 'table, or there is and no one is admitting it). To my way of thinking, platter speed has to be one of the primary functions of a turntable and that manufacturers would be making sure that their products' platter speeds were within strict specifications. At least better than 2% margin of error as is the case with my turntable.

My question is: Is platter speed error a given in this industry or is my 'table actually in need of repair? And, if platter speed is an industry problem, why are we as consumers paying thousands for equipment which actually doesn't work up to expectations?

frepec

Showing 4 responses by isanchez

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isanchez
276 posts
 
Frepec,

Your speed issues are not uncommon with turntables without a speed controller. I found myself in your same situation when I had a Wilson Benesch turntable and ended up buying a speed controller for it. I went for the Clearaudio Synchro since it also cleans the power fed to the motor, besides controlling the speed.

It is possible that the speed is faster because of voltage/frequency you're getting from the wall outlet.

I totally agree with you in that all turntables should come with some sort of speed controller if you spent more some serious cash on it, since accurate speed cannot be guaranteed by the manufacturer.

Pro-Ject makes some affordable speed controllers, if you're interested in not spending much. I think the cheapest speed controller will be better than no controller at all. It's puzzling to me that Pro-Ject can come up with a very affordable speed controller, but the higher-end companies can't.

All the best,

iSanchez
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isanchez
276 posts
 
Frepec,

I totally agree with you. It seems that we, as audio equipment consumers, have grown complacent with the idea that it is not so relevant for analogue playback to have speed control with a turntable. The fact that there are so many turntables in the market without any sort of speed control is really puzzling to me. This is one of the main reasons why I sold my previous turntable and got the Acoustic Signature Mambo. I think most of the AS turntables come with the same power supply/motor controller.

There seems to be a new generation of turntables that take the notion of speed control a step further. There is the new Clearaudio Innovation turntable that reads the speed of the platter via a sensor and corrects it accordingly. Another turntable with its own speed correction technology is the Grand Prix Audio Monaco. To the best of my knowledge, both of these turntables are in the 20K neighborhood. It think it is a matter of time before these technologies drip down to more affordable turntables.

I think in some cases a turntable may not come with a motor controller in order to trim down the cost, but the manufacturer should warn the consumer that the motor controller is a necessity for the serious listener, which is the target consumer for the high-end turntables.

Best,

iSanchez
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isanchez
276 posts
 
In many instances, the power that comes from the electrical outlet is unstable. This instability tends to affect the speed of many turntable motors. So it is quite possible that electrical power is one of the main causes for your turntable to run faster.

As mentioned in previous posts, there are other variables that also affect the speed of a turntable. The leveling of the bearing will affect the speed of a turntable in many cases. In this scenario, the weight of the platter plays a more active role. In my particular case, I set a calibrated PRO 3600 digital protractor on top of an Avid 45 adapter to level the platter bearing. The PRO 3600 has accuracy of 1/100 degrees. When my platter is perfectly leveled, speed accuracy of 33 1/3 is dead on. The platter will play at this speed for as long as the turntable is absolutely leveled.

If a turntable uses a bearing well with oil, as the oil dries out, one should expect the speed to slow down with it. Also, Many oils will change viscosity as their temperature changes. Since the bearing friction will increase the temperature to some extent, one can expect the turntable to go through some speed changes.

The Synchro is a power re-generator, so it will output whatever frequency you set it up to, regardless of the input frequency from the electrical outlet. What you're experiencing with the Synchro is normal.

Best,

iSanchez
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isanchez
276 posts
 

I keep track of the frequency and voltage coming from the wall outlet, and very few times I get to see 120v @ 60Hz. This varies from different utility companies though.

Best,

iSanchez
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