LP12- Power Supply- Need education


I have read a lot about different options to upgrade the analogue power supply.
A phono stage need to amplify micro signal would require very good power supply to ensure there is minimal noise interfere with the signal.
I read about Lingo and other power supply articles, however they never mentioned about the science behind it.
How could a power supply powering a motor will introduce noise to the cartridge especially belt drive?
How do you measure the noise when playing a record?
Or would  the power supply provide a more stable rotational speed, my speed measurement on the turntable shows very consistence rpm once it is playing?
I really do not understand why a Lingo power supply cost so much but cannot provide an improvement with a measurable results.
Could someone educate me.
msnpassion
There are two types of DC motors: Brushed (DC) and Brushless (BLDC).  Even with a brushed DC motor, the current through the windings must be reversed as the motor rotates;  this is done automatically by the brushes and the commutator ring, so a steady DC current is all that is needed from the supply.  BLDC motors do not have mechanical commutators to change the current, they are electrically commutated (EC) by using Hall sensors to signal the controller when to switch the currents.  When operated this way, they still behave as DC motors where the drive voltage determines the speed.  The speed of DC and BLDC motors operated this way are dependent on the drive voltage, torque load and temp, making speed regulation more difficult, especially without feedback.

  BLDC motors can also be operated as a 3 phase synchronous AC motor where the speed is determined by the frequency of the drive signal, which is made up of 3 sinewaves 120° out of phase.  The electronics to accomplish this correctly is more sophisticated than EC control, but it produces smoother operation, less cogging and more precise speed control.  The SOTA Eclipse motors use a 3 phase AC controller.  The speed can be controlled very precisely without feedback.

You can find more information at these links:

https://en.wikipedia.org/wiki/Brushless_DC_electric_motor


http://www.turntablepsu.com/technology.html#BLDC
@phoenixengr   I believe in the Linn Radikal upgrade the motor is a brushed DC design.
@daveyf- I believe that is correct. If I’m not mistaken, it also uses feedback from the platter for accurate speed control.

Mark Kelly had an innovative design for a brushed DC motor controller that did not require speed feedback from the platter, but as far as I know, he never pursued it.
@phoenixengr That is also correct. There is an optical reader that mounts under the platter and reads a mark on the platter every revolution.
@phoenixengr - Mark Kelly had two very unique designs for open loop controllers, the brushed DC controller being one of them. The other was the Synchrotron AC-1, which was an open loop controller for synchronous AC motors. That controller was the most accurate open loop motor controller I’ve ever used, and every conceivable motor parameter (frequency, amplitude, phase angle, harmonic distortion, etc) could be adjusted. This level of parametric adjustment allowed cogging to become nearly non-existent.

I still own both.