2. analog
  3. 150307-111654

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
Post removed 
lewm
13,771 posts
 
Dear Bdp, I’d like to hear from Bill Carlin himself, if he really said what you say he said. If Bill did say that, of course I would yield to his far superior level of knowledge, compared to mine. But to take your point, first of all, DC is Direct Current, meaning it has no frequency; therefore it has no phase differential. So there can be no such thing as "3-phase DC". In a DC motor that operates off the wall socket, there is a conversion of AC to DC. (Teres had a DC motor that incorporated a battery option, I think.) I am guessing that AC to DC conversion may be happening in the new SOTA Eclipse motor AFTER the power supply works on the AC side to regulate speed. I really don’t know what’s going on there, but I also saw what maybe you saw on the SOTA website. It does mention the term "3-phase DC", which is an oxymoron. They’ve probably dumbed it down for us audiophiles. But most of all, if you read my earlier post, I too recommended the Eclipse upgrade, so we have no argument there. I don’t think a DC motor has inherently more torque than an AC motor. One DC motor may have more torque than another AC motor, etc. But there is no general rule. And anyway, where did I say that AC motors were superior to DC motors? (Your comment suggests that I did say that.)

I do know that the original AR X turntable was built as you say, with the motor on firm support and the platter suspended. Probably that was also the case for the Thorens TD125. (At one time or another, I owned both.) In my opinion, that’s a problem of design for suspended belt-drive turntables that has to be dealt with in one way or another in order for platter speed to remain stable when the suspension is disturbed. My AR X and my TD125 were no great shakes for speed stability. Finally, I have not been bashing the Linn LP12 or even the SOTA; I am just pointing out some issues. Nothing is perfect.
daveyf's avatar
daveyf
3,083 posts
 
Ivor T used to believe that AC motors were the only way to go, that changed with the introduction of the Radikal...and its DC motor. ( Linn was never supposed to be interested in digital either...that also seems to have changed over the years.) 
Nonetheless, owning both the Radikal D with its DC motor and prior, the Lingo and Valhalla platforms with their AC motors, I can say that the Radikal D is a MAJOR step up in SQ over those speed controllers/motors. 
bdp24's avatar
bdp24
10,280 posts
 

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 ;-) .

lewm
13,771 posts
 
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.
More to discover