I get quite correct 33 rpm (a tiny bit slow) by setting the SDS to 66.00 hz, the top value, and then position the player (or the Samas, but that is harder to do) so that the nylon thread gets a good amount of stretch. The thread is 1 mm thick. For 45 rpm, I get OK speed at 90.00 hz (note, I have 230volts/50hz electricity), although I hear some hum from the motor.
Storyboy, I notice you use a rubber belt rather than a thread in your flywheel system, is this because it sounds better in that configuration? Could you describe the change the flywheel makes to the sound? Is it possible to order the flywheel as a separate part?
Podolaw, thanks, I will check out.