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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 5 responses by frepec

frepec OP
17 posts
 
Thanks to all who have taken the time to respond to my questions. I would like to clarify something which may not have been apparent from my post. That is, I like the Atlante. I like the sound I get and I like the "fit 'n finish" of the product and I like the way it looks. In no way was I implying that Transrotor turntables were less than quality products and I really have no desire to replace mine. That said, I am getting the idea that platter speed is a problem for owners of other brands as well and like Jaytea, have lots more expensive 'tables than I do. It also appears that an outboard speed controller is my only option at this point. That's OK, I just wanted to know for sure.

It still is and probably will remain a mystery to me why we as consumers are obviously not getting all that we are paying for, and yet, we are still willing to pay for products that require us to invest in more outboard products to get the original product to work correctly.

Thanks again for replies. One more reply. To Thsalmon: I did use a strobe with a stylus groove.
frepec OP
17 posts
 
I'm beginning to get the idea, now. I did some checking and it does seem to be that most high end turntable manufacturers also have speed controllers as part of their product line. I think that johnbrown has it right. AC motors are not reliably accurate and thus require speed controllers to get them dialed in. It does seem like a marketing ploy. Let the buyer discover he has a speed problem and then sell him a speed controller. It's beginning to become evident to me that speed problems are the nature of the business and that there is most likely nothing wrong with my equipment. I just think that with all the technological advances that have been made in the home audio field, that making an accurate platter drive motor should not be that big a deal. Not being an electrical engineer, I could be way off base with that statement.
frepec OP
17 posts
 
Tom:

Thanks for responding. My 'table is in my house so temperature is not an issue, but since the bearing is oil lubricated, I do let it "warm up" by letting it run for a few minutes before I play anything. All speed measurements were taken under warmed up conditions. Also, I am aware that changing the distance between the motor and the plinth will effect platter speed. I have played with this on several occasions. In order to get the platter speed close to 33 1/3, my motor has to be so close to the plinth that the belt sags and speed consistency suffers. I even bought two new belts and that made no difference.

When you say "If you cannot get 33 1/3 from a table without a speed controller, something is wrong," I agree totally. But from what I am hearing and from over a year of on and off investigating, that doesn't appear to be the reality. I seems that most turntable owners are using some kind of speed controller just to get correct platter speed. This exercise on Audiogon,is just the latest in a series of investigations I have made into this subject. I could be totally off base here, but I am becoming more and more convinced that accurate platter speed is not a given when one buys a turntable, unless it comes equipped with a speed controller, as is the case with more expensive 'tables. A review of the replies in this thread seems to substantiate this conclusion.
frepec OP
17 posts
 
Yesterday, I borrowed a Clearaudio Synchro and installed it in my system. Using the Clearaudio readout in hertz mode, to get my 'table to run at 33 1/3 rpm, the hertz indicated on the screen is 57.2. Setting the Clearaudio to 60 Hz makes my 'table run too fast, about 34 rpms which is the speed I was getting before I had the speed controller in the system (see original post). All along everyone I talk to about my speed problem has been telling me that my electrical power is the cause. I have one question: To me, these results do not appear the substantiate that claim. Am I all wrong here?
frepec OP
17 posts
 
The power generated in the US is supposed to be 60 Hz by specification. Granted there is a lot of variables to this rule. However, I have been told from several sources that turntable platter speed motors are built to run off of this specification. Therefore, if that is true, then at 60 hz, theoretically speaking, the platter speed should be right on at 33 1/3 rpms. That isn't the case here, however. So I guess what I am getting at is: Isn't it possible that the motor which came with my turntable is out of spec from the get go since at 60 hz it runs at approx 34 rpms?
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