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

lewm, it was on the VPI Forum (as well as others) that Carlin voiced his opinion of the superiority of DC motors over AC ones in turntable applications, and he was also brutally honest in his critique of the Hurst AC motor VPI installs in their tables. He and Harry and Mat Weiseld really "got into it" on one thread, and Harry locked it. It's still viewable, however. I would provide a link to it, if only I knew how!

I'm unable to discuss what constitutes a 3-phrase DC motor/power supply/etc., as that is over my head technically. I'm only repeating what, not SOTA, but Bill Carlin said on the subject.

lewn, I did not say, nor even suggest, you had stated AC motors are superior to DC motors. Where did you get that impression? The same is true regarding the bashing of the Linn LP12 or SOTA.

The "problem" of a base-mounted motor in a suspended sub-chassis design is of interest to me, as the VPI Aries 1 I recently acquired has it's motor (the Hurst AC, of course, though the SOTA DC is being made available for it) mounted in a 15 lb. pod separate from the plinth holding the platter and tonearm. That is in effect no different than an AR/Thorens/Oracle/Linn, except for the fact that the plinth sits on "isolation" cones, not springs. But I just replaced those cones with Townshend Audio Seismic Pods (springs in a bellows-type rubber sleeve), for true isolation (cones provide that down to only 10Hz or so, not nearly low enough). Ya just can't win! But then, the Seismic Pods absorb vibrations, so perhaps their presence does not break the motor/platter/arm/cartridge mechanical integrity. Again, over my head ;-) .

No problemo.
if the new SOTA Eclipse motor is DC, and unless Carlin has totally changed his original design, I would bet the control is done on the incoming AC before it’s converted to DC to drive the motor.
If you guys are interested in what Bill did you might was to look on the DIY site.  There are quite a few threads on 3 phase controllers there.  Bill helped a lot, to say the least.

If I am not mistaken,  he is using a 3 phase AC frequency generator with even more bell and whistles than what we built.  He is running a 3 phase DC motor on 3 phase AC.  What Lewn has is a single phase frequency falcon or eagle, which I use to have.  The only DC that is going on is in the name.

Bill is a sharp cookie. Glad to see Sota realize this.

Enjoy the ride
Tom
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.