VPI SDS exact speed in .... 40 minutes?

I bought a VPI TT with double motor/flywheel. Normaly use to take about 30 -40 minutes to get the exact speed. after 10 minutoe is very close but to be exactly at 33.333 needs that time. Do you consider this is normal?
It should be at the correct speed in a few seconds. Do you have the right amount of bearing grease in the flywheel bearing well ? as well as in the platter bearing ? Too much grease can cause them to run slow, all you need is a very small dap at the very end of each shaft, right on the ball bearing, prior to slipping the platter and the flywheel on.

Good Listening

Theres an worthwhile app to check rpm of turntables...irpm...and it works
Thanks for the responses. I use oil in the flywheel and the platter bearing, not grease. Do you consider that using grease will help?. By the way, my platter is the one that is half black acrylic and half aluminum.
I would think that oil would run out of the bearings due to gravity leaving the thrust plate high and dry, i have only ever used white lithium grease in my many many VPI based tables and have never had any trouble.

Viper Lube

Best of luck

will try that Peter
I respectfully disagree with bpaudio. Well type bearings such as comes with those older platters neee oil not grease. I have tried white lube in my TNT and it took forever to achieve a stanle correct speed. Inverded bearings need grease to prevent the oil from just running off the bearing and thrust plate.
W2 - Are we not talking about inverted bearings here ?

Good Listening

Why speculate? Call Harry. Or Matt.
The half-black and half acrylic platters are for earlier TNT and Aries tables. (I've got one) They use well-type bearings. So I don't think you're discussing inverted bearings. They should be oiled, not greased.

Not sure about the bearing on the HR-X.

But I don't think the bearing is the problem. I would look upstream at the SDS. How long should an amplifier take to reach stability? How long for a tone generator?

That's why I suggest a call to VPI.
Why hasn't anyone suggested belt slippage as the cause of this problem (and it IS a problem, not "normal")? I could envision that a high mass platter might slip the belt for several minutes at start-up, if the motor is relatively weak and the belt is not grippy.
The Dual motor Flywheel drive station for sure use a inverted bearing, which should be greased ad I described above, too much grease will cause it to bind up.

I use the SDS on all my belt drive tables along with the Dual motor drive station and it is very stable and up top speed in a few seconds, speed is checked with the Southerland time line.

If your plater is older and do use a well bearing then indeed you should use a thin viscosity oil on the platter bearing.

As far as belt slippage, possible, I use 4 belts from the Dual drive station to the platter so that to me has never been an issue.


Good Listening

Peter, do you consider that maybe the problem would be something inside the motors? any idea how to verify if the motors are running ok?
I suppose that is a possibility, but a motor is a pretty simple mechanical devise, and of the many many of them i have had come through here I have never had any issues with the motors. Did you buy a new Dual Drive Station ? How are you checking the speed ? Are you using a SDS ?

If you table ran at speed before you added the dual drive station then the main platter bearing is not the issue.

The only issues I have had is if too much grease is added to the inverted bearings they can bind up causing the speed to vary.

I don't know where you are located but is your close to us here in San Diego your more than welcome to bring it by the shop and I can take a look at it for you.

Good Listening

Thanks for your offer Peter but Im in the opposite side: Florida.

Yesterday what I have done is run the platter with just one motor and then the other (bypassing the flywheel and one of the motors each time). What is interesting is that the speed is perfect since the beguining. That makes me think that is a flywheel problem, but honestly don't know how that happens: it runs smooth, no noises and have tried using grease and oil with exactly the same results. Any idea?

what Im going to try this evening is run the same test without the SDS and see what happens. What it is interesting is that I need to set the Hz in 58.1 to run the table at 33.33 in the SDS, and should be at 60hz or very close to that right?
Your actual SDS setting is not that relevant it is what ever it is to run at the correct speed, that the setting is not exactly 60Hz is caused by the product the small deviations in all the mechanical interfaces from the motor to the platter. My SDS on one of my tables here in the showroom is set at 59.29.

What belts are you using from the motors to the flywheel ? maybe that is where the culprit is, I use these AS568A-155 Buna N 70 Only use one o ring per motor to the flywheel, then use 4 of the long ones from the flywheel to the platter if that is possible for you. The long ones are not readily available - we make them here from the same type material but thinner and available in 100M spools. If you need some let me know what length and I can make them for you.

Best of luck

Thanks Peter, just sent you an email to pbnaudio
Agree with pbnaudio - the actual frequency reading on the SDS is irrelevant; it's easy to prove that with different mass centerweights: lighter ones will need lower freq settings, while heavier ones will require higher. The good news is that you can get extremely accurate speeds with the SDS.
Thanks Ack. After emails exchanged with Peter, one of the couses would be the thickness of the small belts that goes from the motor to the flywheel so I bought new ones. As soon as I receive them will post the results. thanks to all for your input.
OK greak and sorry, I got the weight/frequency thing backwards