[Bret L]

Can either motor be run on either 50 or 60 Hz for different speeds
(for applications other than turntables) or is each dedicated to its
frequency for all applications?

**No. The pulley diameter is changed to accommodate different frequency of
operation. Motor windings are arranged as serial of parallel to accomodate
117VAC or 220/240VAC.

He was not asking about voltage. The use of the different pulleys
should tell you that the motor, itself, will run at different speeds
when driven at different frequencies.

If so how much variance to (vary/trim
play speed) is considered OK by the maker?

**Presumably none.

If these are standard synchronous motors (and I believe they are),
they can run on 50 or 60Hz or, indeed, other line frequencies as well.
Of course, the speed will be proportional to the line frequency.

I have built variable-frequency drives for such motors.

Kal

A synchronous motor turns at a speed which is directly a function of
its supply frequency, but for a given frequency different motors turn
at different speeds based on the number of poles in the motor. Since
the number of poles has to be some integer, and if I am not wrong, in
a single or two phase system, an even one, there are a finite range
of speeds synchronous motors can run at at any given frequency. So
without gears. you just are not going to have the same shaft speed at
both 50 and 60 rpm.

Now, they could use and sometimes do use the same motor at 50 and 60
Hz with different pulleys and sometimes both the pulley and motor are
different. Which of those two situations is found in the Linn
turntable si the essential question here. Linn tend to be penisish in
answering such inquiries. There attitude is that the dealer is there
to burp, change and feed you and if you don't like it, tough. the
dealers themselves often don't know and often won't provide
information if they do.

Trevor tends to be penisish as well.