Need to adjust the speed every time I turn on turntable
AC motors are locked to the drive frequency, but the wall power frequency does vary a small amount over short periods. This will manifest itself as a wavering on single notes, but will not show up as speed drift over longer periods of time. Long term speed drift is caused by changes in the belt and bearing lubrication over time and changes in stylus drag from the beginning of a record to the end. The speed of DC motors is more difficult to control than AC synch motors. Even with tight DC regulation of the voltage, the motor speed will be affected by torque load and temp. Some of the OL motor controllers compensate for speed changes with load variation (stylus drag), but without temp compensation, the speed of the motor will still wander. A synthesized PSU will lock the speed of an AC synch motor to a quartz reference, but as I posted above, this does not guarantee constant PLATTER speed. Even with perfect motor speed control, the platter speed will drift over time. |
I had stopped listening to albums because the speed fluctuations drove me nuts. It was very audible. I finally bit the bullet and sent it back to Sota for a new motor, board, speed control and maglev bearing. The sound is now amazing. I can clearly see that it runs exactly at 33.3 and it sounds just as good. My advice, stop playing games with your table. Either fix it or replace it. DC motors get old. |
@mijostyn, speed drift is quite common with origin live dc motor. See the faq https://www.originlive.com/support/hi-fi-problems-troubleshooting/dc-turntable-motor-problems/ |
