Belt driven Synchronous Motor vs. DC Motor for Record Players

Most user say, the best kind of motor for this aim is a DC motor.
Are there also a benefit for the synchronous motor in opposide to a DC motor?
Thanks for advices.
some URLs for both kind of motors:

Papst DC Motor
"GS 38.09" oder "VDC-3-43.10" (937 4310 602)
DC-Motor - VDC-3-43.10 B00 von ebm-papst
http://img.ebmpapst.com/products/datasheets/VDC34310B01-615582.pdf
und unter posting 24 unter
Papst Motor VDC-3-43.10 - Phono - Restaurierung und Selbstbau - Analog-Forum

Mclennan Synchronmotor MV86111
Motors
http://www.mclennan.co.uk/datasheets/european/synchronousdata/990411131813.pdf
http://www.mclennan.co.uk/datasheets/european/synchronousdata/mvdatasheet.pdf
Dr. Fuss Motornetzteil - Frank-Landmesser.de
 
My father has an old Winco turntable, and uses asychronous AC motor, and still works pretty fine, including the strobo test.
 

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I would say that AC or DC motor is not the defining parameter, once a good motor is chosen, it is a matter of how the speed of that motor is controlled.

DC motors can be quite good but they do require a very well designed controller to maintain the speed and prevent issues with speed drifting.

AC motors have been used for quite a long time and in some very high end quality turntables. They rely on the consistency of the AC waveform driving them (usually the AC frequency of your line supply).

I am going the way of AC motors, as they are in my favourite Thorens, Linn and Ariston turntables. I am currently building a controller project for AC sync motors. If you are interested in my thoughts about them, you can check it out at my blog.

Audio This 'n Audio That

SoundBound
 
Similar, well they are both DC motors- but that's it. The Linn uses a Maxon motor, the Pabst motor is a far more complicated animal altogether with hall sensors on the rotors. The Linn set-up is just a simple optical tachofeedback with a very slow feedback loop on top of a current sensing feedback arrangement.

The Linn radikal speed stability isn't that good. No better than a Lingo, but the motor is lower in mechanical noise.
 
Similar, well they are both DC motors- but that's it. The Linn uses a Maxon motor, the Pabst motor is a far more complicated animal altogether with hall sensors on the rotors. The Linn set-up is just a simple optical tachofeedback with a very slow feedback loop on top of a current sensing feedback arrangement.

The Linn radikal speed stability isn't that good. No better than a Lingo, but the motor is lower in mechanical noise.
Thank you for this advice.go also to http://www.diyaudio.com/forums/analogue-source/2971-linn-lp12-motor-malaise-3.html
Most user say, the best kind of motor for this aim is a DC motor.
Are there also a benefit for the synchronous motor in opposide to a DC motor?
Thanks for advices.
go also to
http://www.diyaudio.com/forums/analogue-source/2971-linn-lp12-motor-malaise-3.html
some URLs for both kind of motors:

Papst DC Motor
"GS 38.09" oder "VDC-3-43.10" (937 4310 602)
DC-Motor - VDC-3-43.10 B00 von ebm-papst
http://img.ebmpapst.com/products/datasheets/VDC34310B01-615582.pdf
und unter posting 24 unter
Papst Motor VDC-3-43.10 - Phono - Restaurierung und Selbstbau - Analog-Forum

Mclennan Synchronmotor MV86111
Motors
http://www.mclennan.co.uk/datasheets/european/synchronousdata/990411131813.pdf
http://www.mclennan.co.uk/datasheets/european/synchronousdata/mvdatasheet.pdf
Dr. Fuss Motornetzteil - Frank-Landmesser.de

To this topic there is since a long time this already existing thread:
http://www.diyaudio.com/forums/analogue-source/95411-dc-vs-ac-motors-newbie-needs-help.html
 
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I would say that AC or DC motor is not the defining parameter, once a good motor is chosen, it is a matter of how the speed of that motor is controlled.

DC motors can be quite good but they do require a very well designed controller to maintain the speed and prevent issues with speed drifting.

AC motors have been used for quite a long time and in some very high end quality turntables. They rely on the consistency of the AC waveform driving them (usually the AC frequency of your line supply).

I am going the way of AC motors, as they are in my favourite Thorens, Linn and Ariston turntables. I am currently building a controller project for AC sync motors. If you are interested in my thoughts about them, you can check it out at my blog.

Audio This 'n Audio That

SoundBound

Hi, any progress on the ac sync controller?
Have a few decks using papst motors and want to build a speed controller, thanks.
 
The advantage of the middle of the United States is that the AC mains power frequency is so stable, that a synchronous motor turntable never shifts pitch in a way that my pitch trained ears can detect. (I was a double reed player in school band of some skill, where the pitch is controlled 80% by the player, not the instrument). The disadvantage of the middle of the United States is that there is not the chance to hear high end audio product, nor much interest by my neighbors. The electronics stores stock here mostly refugee products the company got a big discount on because they won't sell on the coast. So the very best turntables I have heard, I have owned, both with synchronous Ac motors and belt drive. A 1961 AR turntable, with tracking limitations, due to the arm and poor suspension, and a 1978 BIC 940 changer, with better suspension and arm, and a manufacturing defect that I repaired that made it affordable. Neither turntable had as much wow or flutter as say, a Gerrard (wow, rumble) or a tape cassette deck (annoying flutter).
In any local where local generator power is common, I'm sure DC drive would be a much better choice.
 
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I have worked on many DC Direct Drives. Every once and a while, to keep the strobe honest, I do a Wow and Flutter and Drift test with a meter. Since I only work on Technics 1200 thru 1800s the newest of these tables are around 35 years old, many are over 40 years old. With just lubing and de-oxing some VRs, this is typical performance of these DC DD TTs:

Wow Flutter SL 1400 7 May 2013 - YouTube
 
I use a DC controller motor system designed by Bill Thompson. Below is just a section of his write up on design/control of the motor system. I also linked his website were he has a complete write and schematic of the controller board. It is a fantastic little piece of gear.

“PIC microcontroller. The time base is an 8 mHz crystal and the speed adjustment is accomplished by the encoder. Whenever an adjustment is made the new timing information is stored in an EEPROM in the PIC chip so the speed settings are remembered when powered off.”

Turntable DC Motor System – BillThompson.us