2. analog
  3. 1320876538

Turntable speed accuracy

There is another thread (about the NVS table) which has a subordinate discussion about turntable speed accuracy and different methods of checking. Some suggest using the Timeline laser, others use a strobe disk.

I assume everyone agrees that speed accuracy is of utmost importance. What is the best way to verify results? What is the most speed-accurate drive method? And is speed accuracy really the most important consideration for proper turntable design or are there some compromises with certain drive types that make others still viable?
peterayer

Showing 2 responses by palasr

palasr
528 posts
 
Don,

You are simply wrong. Stylus drag will slow down any turntable, regardless of platter weight; it merely changes the period over which it occurs due to inertia. And yes, the 60Hz mains supply does fluctuate enough to be completely problematic.
Then again, if you can't hear it, more power to you.
palasr
528 posts
 
Downunder,

Yup, that will irk you. Alas, that's a fine example of a poorly designed drive system; there's a reason the SDS was developed and that goes back to the AC mains. Trying to accurately derive 33.3 RPM using a crude phase shifting capacitor and hoping that the frequency of the incoming AC is stable enough to do the job is bad engineering. While frequency accuracy (and adjustablity) is one issue, it doesn't begin to address waveform shape, harmonic distortion, phase amplitude and shift, and all the other interesting things that go into generating a waveform suitable for driving a synchronous AC motor.

DC motors have their own set of problems...
More to discover