Direct Drive vs. Idler Drive vs. Belt drive

Hi @lewm ,

People think that belt drive is a black magic, technically perfect solution.
You just need a heavy platter on a good bearing and you have very low, inaudible level of Wow and flutter. But it doesn’t work this way. At least, mid-price belt drive turntable have a very perceptible level of Wow and flutter, and it is much worse than rumble that good designed, affordable idler drive like Lenco has.

Regards,
Alex.

In a synchronous motor the rotor lags behind the rotating field. This angle changes with changes in load There are subtle differences between motors, even with apparently the exact same build. This results in slight differences in this lag angle for a given load between (identical) motors
In a multi motor design, this means that one motor will be the master and the other(s) will slave this. 
The master providing the bulk of the drive torque. 

Consider the implications of this characteristic when 2 or more motors are used to drive a platter    

Thucan, more wishful thinking. If you can't afford new stuff that is fine. Buying used gear that is within your budget can be a smart way to increase the performance of your system.  But trying to compare a D103 in any form to a Lyra Atlas or an Ortofon Windfeld Ti is ludicrous and delusional. However most do not have speakers capable of resolving the difference so spending the extra money would also be sort of silly.

Alex are you kidding? I would wager $1000 that you can't hear the difference between a cheap belt drive and an SP10 in regards to wow and flutter. Not only can you hear rumble but it also distorts everything else you woofers are doing. And, since when have you made that comparison in a scientific fashion. Let me answer for you. Never.

Lewn, I do not own a Clearaudio Turntable because I do not care for their designs but they are very well made. Way better than say VPI. I do own one of their cartridges and it is well made and quite delightful.
I do not have to have direct communication with either. I only need to see what they are doing, knowing that both are trying to attack the state of the art in their own way. Anyone can make a direct drive table. The motors are readily available. Even VPI managed to come out with one. Belt drives are not that simple. There are complexities under the surface that take careful engineering. It is how ever and this is not IMHO, the most elegant way to make a high performance turntable and the vast majority of turntable manufacturers feel the same way. The vast majority of audiophiles with expensive systems also feel the same way. There are a few new DD turntables that I have yet to hear but the basic problem remains, an oscillating magnetic device directly under an exquisitely sensitive magnetic device who's job is to resolve magnetic oscillation.
Magnetic field strength drops off with the square of the distance. Every centimetre increase in distance between the motor and the cartridge decreases the motors influence over the cartridge by a factor of 10 increasing exponentially. I believe I would prefer an idler wheel drive table over a direct drive (haven't made that comparison) even though I would have to shelve my subwoofers. 
This is why Howard Johnson's made 28 flavors. Some people would rather look at a turntable than listen to it.