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Pioneer PL-41 pitch control?

cal_tyke said:
Regarding the previous posts(s) about the length of belt having an effect on the rotational speed of the turntable. Isn't the rotation speed directly proportional to the ratio of the two pulley diameters (and not the length of the belt)? As long as the pulleys are in motion (ie. the belt is acting to couple the two pulleys mechanically), and the motion is steady (constant rotational speed, not accelerating, in which the elasticisty comes into calculations I guess) then I don't think the belt length should have an effect on the rotational speed of the turntable. The belt has to be about the right length so that it makes effective contact, so the pulleys will turn, and so that it doesn't slip. We change belts because they don't grip as well as they did, or because they start to degrade mechanically (break up), not necessarily because they are a little too long or short. Or does my dim and distant memory of rotational dynamics fail me?
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Reading other AK postings on this, I was struck with the same impression. I believe you're correct.

BrocLuno said:
I suspect that many of these tables have the 50Hz pulleys installed. They would be bigger by design and therefore drive the platter faster.
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I seriously doubt this is the issue. If it were, some AKer would have tried it by now, posted this as the solution, and it wouldn't be a problem anymore. However, since mine HAS the alternate pulley under the platter, I intend to find out.
 
The other option would be to increase the diameter of the platter.

Some Rega Planar II owners who notice an overspeed slow it down with a layer of electrical tape applied to the platter where the belt drives it.

The tape butt-joint must be perfect.

Don't know if this would work for the PL-41 but perhaps it is worth a try.
 
I've examined the two spindles, and there is no doubt that the correct one is installed as it clearly has the smallest diameter.

Though I'm not completely opposed to filing the pulley, I like the idea of the tape on the platter, because if it doesn't work, you can always "undo" it.
 
I've had several PL-41s over the years and every one has been spot on speed. I've not had any complaints from customers about speed issues, either. I always had the factory spec's belts on them.


If belt lengths and widths did not matter manufacturers would not specify one sized belt over another. Both dimensions are very important but width is, at least on most turntables, the more important of the two dimensions. One needs the correct dimensioned belt to get proper speed, lowest noise, and maximum motor and platter bearing life. Plus, on suspended turntables a too tight belt will cause the suspension to be pulled off center. Not good.
 
I agree, my PL-41 speed is fine, I'm using a Pioneer belt.
I have seen speed issues with aftermarket belts, especially with Empire and Fairchild tables,especially the 412 and its 2 drive belts.
bob
 
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