Like I said, that was Empire's claim. I have no idea what the truth of it is, unfortunately. I'm sure somebody more knowledgeable here will chime in.
Thanks for the response. I knew someone would clear it up.The Papst Aussenlaufer motor is actually an induction motor type known as an "Eddy Current" type. It works by inducing eddy currents in the outer shell which then accelerates until it is essentially (but not quite) synchronous with the stator field. The drive to the rotor depends on this relative motion between the stator field and the rotor. The difference in speed is around 2 or 3 percent "slip" which depends on how much load torque it faces. So unlike a synchronous motor, the actual speed is not strictly a function of the AC frequency, but also is affected by the load, and to some degree the voltage. That's really the biggest practical difference. The slip/torque factor is useful as it helps smooth out the torque delivery which makes the motor function better for our purposes.
The Papst physically has three sets of windings so it can, in fact, be wired and run as a three-phase motor. The Eddy Current motors waste a lot of power, but are great turntable motors. The excess power use goes into heat, so the vanes on the motor are critical to long life and one of the reasons the motor acts as a fan (to shed the heat). The Papst draws about 23 watts (mine draws 0.19A at 120VAC), which is pretty inefficient compared to most other types of turntable motor. However, it does deliver the instant torque -- and more constant torque -- than most synchronous motor types available today. It's a real gem and one of the real strengths of the table. To the chagrin of many, Papst stopped producing this motor somewhere around the turn of the century.
The motor pulley has a barrel shape which serves to self-center the belt. It may seem counter-intuitive, but the belt will ride on the thickest part of the crown because every time it moves away from the center, the camber angel will push it back towards the center. It does represent a challenge to replace, since it is an interference fit on the motor shaft.
For those who are really tweaky/geeky, the motor can be wired and controlled via a 3-phase controller. There are several threads around for ways to do this. Google Mark Kelly and see for instance the motor controller he designed and built for user "Grinagog." The advantage of a 3-phase controller is the ability to design and optimize the exact phase relationships for each set of windings. This results in exactly equal pulses for each of the three phases which reduces noise and makes the motor smoother. The stock Empire approach uses a roughly 4uF capacitor to generate/synthesize the third phase from two-phase AC power. Unfortunately, the value of the capacitor is an approximation of the optimum phase, which is one reason why a 3-phase motor controller can make a real improvement in noise and vibration since it can be exactly set for the load conditions and speed of the motor under load.
Over on the DIY Audio forums, the designer of the Falcon/Eagle motor controllers has been posting about a 3-phase motor controller that he's been experimenting with. It's an interesting area (for geeks), and I commend your attention to it. His two-phase motor controllers are fantastic. I use his Eagle controller and Roadrunner tachometer to automatically set the speed on my Empire, so I'm no longer hassling with belts (any belt will do, since the controller uses the tach to adjust exact speed to 33.3 or 45.0).
Hope this is helpful!
View attachment 714450 View attachment 714451
A friend loaned me his 598 loaded with a Zu Denon 103, which weighs 13.5 gr compared to 8.5 gr for the unmodified cartridge. The added cartridge weight meant the CW was run back to the point it was hitting the lid support.
I cut a 1 1/4" length of a 1 1/4" I.D. copper plumbing pipe and mounted it over the CW using rubber shelving material as a spacer. The added weight on the CW made dialing in the VTF very straight forward. Set up this way, the Zu/598 combination run through a Schiit Mani sounds quite good.
Despite getting the results I wanted, I'm a little concerned about the addition of about 38 gr - cartridge and pipe section - and what effect that might have on the bearings.
Doug
This is a beautiful table. That arm is perfect for that table. Awesome job.Well, it's finally finished and have to say a big thank you to a fellow AK'er, oldsch00l, who's combo I copied. When I saw his empire turntable some months ago I just knew I wanted one just like it. The marriage of the vintage yet timeless design coupled with a newer style and well respected tonearm appealed to me greatly.
When I finally spotted one on the bay going for a song I grabbed it quick. It was untested and part of an estate sale so I didn't know what to expect. When it arrive two days later I was very happy that the condition wasn't horrible and that the motor worked very quietly.
All I have really done to it is clean everything up, sand and wire wool the wood and metal, clean out and re-oil the bearing, put a seal coat on the wood, fit isolation spikes/feet and fit a new tonearm. With the exception of the tonearm and the spikes it is no different than the day it came out of the factory.
I decided not to do any damping to the top plate or platter as I wanted to see how it sounded in stock form, which I have to say is very good indeed.
The tonearm is the Linn Ittok with Audio Technica AT 32e II LOMC cartridge. The rest of the system comprises Audio Technica AT 700T step up transformer, Copland CSA 18 amplifier and Proac Tablette 50 Signature speakers.
To say I am very happy with the outcome is an understatement. For a 50 year old turntable the condition, mechanics and design is awesome. To the man on the street this looks like some funky new turntable from Europe.
As for the sound, well it is everything everyone has ever said about these turntables, accurate, lively, musical, etc. It reproduces instruments in such fine detail with such accuracy in tone. It is very very quiet in the silent passages and you forget you are listening to vinyl at times, it is so quiet.
Here are the pics.
. . . The Papst physically has three sets of windings so it can, in fact, be wired and run as a three-phase motor.
This is a beautiful table. That arm is perfect for that table. Awesome job.
I don't know about your Papst motor in your Empire, but I have had mine tour down to parade rest and It only has three leads (purple, blue & orange) and two sets of windings. It only has two sets of windings which is why the capacitor is required. Without the cap the windings would be 180 degrees out of phase( one of the three wires is common to both sets of windings) and no rotational magnetic field could be developed to cause the rotor to spin (the magnetic field would simply do about faces and the rotor would remain stationary unless you spun it in one direction or the other). The capacitor in series with one of the two sets of windings provides a 90 degree shift in in the phase of the voltage from that supplied to the other (first) winding. This has the effect of telling the magnetic field to do a "right face" every half cycle, or 180 times a second and this creates a rotting magnetic field the rotor can follow. Three phase motors do this with three leads and three windings because each of the three phases of the 3 phase system are already offset by 120 degrees because this is how that voltage is generated and the rotating magnetic field is easily produced. Three-phase motors will not work in single phase household systems (there are some old-timer tricks that can be used as a work around, but if you thought your Papst motor was inefficient...). You can hook a three phase source to the Papst motor if the line voltage/ current is carefully controlled , but you are still left with a two phase motor because in the end you only have two sets of windings not three (therefore what's the point?)The Papst Aussenlaufer motor is actually an induction motor type known as an "Eddy Current" type. It works by inducing eddy currents in the outer shell which then accelerates until it is essentially (but not quite) synchronous with the stator field. The drive to the rotor depends on this relative motion between the stator field and the rotor. The difference in speed is around 2 or 3 percent "slip" which depends on how much load torque it faces. So unlike a synchronous motor, the actual speed is not strictly a function of the AC frequency, but also is affected by the load, and to some degree the voltage. That's really the biggest practical difference. The slip/torque factor is useful as it helps smooth out the torque delivery which makes the motor function better for our purposes.
The Papst physically has three sets of windings so it can, in fact, be wired and run as a three-phase motor. The Eddy Current motors waste a lot of power, but are great turntable motors. The excess power use goes into heat, so the vanes on the motor are critical to long life and one of the reasons the motor acts as a fan (to shed the heat). The Papst draws about 23 watts (mine draws 0.19A at 120VAC), which is pretty inefficient compared to most other types of turntable motor. However, it does deliver the instant torque -- and more constant torque -- than most synchronous motor types available today. It's a real gem and one of the real strengths of the table. To the chagrin of many, Papst stopped producing this motor somewhere around the turn of the century.
The motor pulley has a barrel shape which serves to self-center the belt. It may seem counter-intuitive, but the belt will ride on the thickest part of the crown because every time it moves away from the center, the camber angel will push it back towards the center. It does represent a challenge to replace, since it is an interference fit on the motor shaft.
For those who are really tweaky/geeky, the motor can be wired and controlled via a 3-phase controller. There are several threads around for ways to do this. Google Mark Kelly and see for instance the motor controller he designed and built for user "Grinagog." The advantage of a 3-phase controller is the ability to design and optimize the exact phase relationships for each set of windings. This results in exactly equal pulses for each of the three phases which reduces noise and makes the motor smoother. The stock Empire approach uses a roughly 4uF capacitor to generate/synthesize the third phase from two-phase AC power. Unfortunately, the value of the capacitor is an approximation of the optimum phase, which is one reason why a 3-phase motor controller can make a real improvement in noise and vibration since it can be exactly set for the load conditions and speed of the motor under load.
Over on the DIY Audio forums, the designer of the Falcon/Eagle motor controllers has been posting about a 3-phase motor controller that he's been experimenting with. It's an interesting area (for geeks), and I commend your attention to it. His two-phase motor controllers are fantastic. I use his Eagle controller and Roadrunner tachometer to automatically set the speed on my Empire, so I'm no longer hassling with belts (any belt will do, since the controller uses the tach to adjust exact speed to 33.3 or 45.0).
Hope this is helpful!