Imagine a CPU doing that? Even if the crystal were of the cheapest type, it can never be audible! Why does my precious turntable lag? For the inadvertent reader, the clock signal(s) frequency entering the CPU is governed by a feedback circuit controlled by a quartz crystal. A much complicated way of saying by the clock chip or chipset.

This is no fun. I'm listening to Liszt's first piano concerto and, all of a sudden, the pitch goes down. I had to stop the music. I think in the future I'll go back the audio CDs and leave these audio subtleties for the vinyl and tube amplifiers fans.

Get a turntable with a belt drive.

They sell bearing replacements for direct drive turn tables. Yours are probably going bad.

My Bang and Olufson Belt drive from the 1970s is still working strong and I have a spare belt in a
ziplock bag for when I need it.

I have probably about a 1000 albums. I go to good will and pick up vinyl for about .50 to $1.00.

Great! Yes, I've been told direct drive is low end. And now I believe it. Wouh, Bang and Olufson?!! I can't get the original belt for a middle priced Yamaha, but I think it bits the JVC.

I would not normally notice the drop in pitch. Need to be in a maximum alert condition to be aware of it. So, waiting to go back to normal.

My belt drive is a Microseiki and the platter is HUGE. I don't know how many kilos or pounds it is. The belt should not be not too tight, or too loose, just right.
It still works with a loose belt as it has so much intertia, it just takes longer to get up to speed.

To fix a direct drive you will have to take apart the motor, and will probably have a taco tacho some where.

Well, thanks. I've just been told, in a music forum, that direct drives come in two styles: the ones whose angular frequency is locked by a quartz crystal and the ones which are not. It seems mine belongs to the latter category.