Turnable database with TimeLine

Very interesting thread Peter. Thanks for getting it going. I'll volunteer my Grand Prix Monaco to be a test subject, as soon as I can barrow Albert's timeline...

The Grand Prix claims highly accurate speed control (from their web site):

"DSP Signal Processing / Active Feedback Loop Technology:
Our speed control features a CPU utilizing a Digital Signal Processor that interrogates and maintains the speed of the platter thousands of times each revolution and thereby ensures frequency accuracy and distortion free playback that is simply not possible with conventional types of drive systems. A highly accurate test procedure has demonstrated the speed error to be an extremely low .002%! Speed accuracy equals frequency accuracy, which means there is virtually no distortion on playback."

Peter, one thought on your SME, have you ever cleaned the motor pulley (and sub platter) and then flipped the belt over? I used to do this with my SME 20/2 every 9-12 months and it did seem to sound better...(that is unless you used a new belt for the test)...then I'd replace the belt every 18-24 months...

Thanks Jfrech. I used to clean the belt on my SME Model 10 about once a year. I've just ordered two new belts for my 30/12 which was new in March 2012. I'll clean the belt I have in the next day or two and see if I notice a difference. I sent the TimeLine back to Albert. I just can't see spending $400 on a new one.

Your Grand Prix will be a good addition to the database. Thanks.

Addendum to above post :
The big Micro's use DC motors with frequency generated servos built into the motor. So their response to speed issues has the same issues as the direct drive, the main advantage of the micro's is the large inertia. This would explain why some users prefer the Micros set up with a controlled slip by chalking the thread.
The Final Audio has a high torque ( the 22kg platter can achieve full speed in less than 1 turn ) AC synchronous motor with precision oscillators and 80 wpc power amplifier to lock the speed.
As Lewm alluded in his post the AC synchronous motor responds to phase lag by self correction. This is why AC synchronous motors can run accurately without servos. A DC synchronous motor will self correct to some degree, but the self correction is less sinusoidal and less smooth than an AC synchronous motor.
It is wrong to imply that the Technics SP10 relies on self correction of phase lag - its servos are active all the time, as is the case with the Victor/JVC and Goldmund.

Excellent Post from Dover.
Unfortunately no Audiophile will understand it :-)

Lewm
Interesting you mention the Kodo Beat. I have been following the evolution of this TT with interest, given it uses similar principles to the Final Audio.

01-04-14: Richardkrebs
The Beat appears to uses electromagnetic drag to "pre load" the motor. Moving the rotor back in phase relative to the rotating field.

Richardkrebs statement is wrong. It is the bearing that is preloaded in the Kodo. For those that have a grasp of basic engineering principles this is a common technique to assist with speed stability. Garrard used it with their eddy brakes. By including a drag component in a moving bearing the motor is always loaded to a minimum level. Preloading the motor so that it is working at a minimum level can help with speed stability.
I quote from the designer of the Kodo Beat review in Stereomojo :

The Beat has only one moving part: the bearing. Since this is the only internal source that can impart noise to the record, much care was taken to develop the bearing. Over engineering describes it nicely. It has a 25mm diameter spindle that is capable of handling a 100 pound plus platter (and yes, I did try one). There is a degree of resistance built in to the bearing and it too can be adjusted.

Now in terms of the AC motor itself, I quote from the manufacturers website:

The issue with DC motors is that their speed is affected by the load. That means they need a control circuit. The control circuit can make the average speed near perfect but this is achieved by constant speed adjustments so there will be constant small speed variations. Many high end tables have used extra mass in the driven rotational mass (platter) to help hide the speed corrections.

The answer came in the form of a huge 3 phase AC true synchronous motor. What makes this motor the best choice for a turntable is that its speed is not affected by load changes such as stylus drag and bearing oil temperature. When the load changes, such as stylus drag (yes, it is real) in complex music passages and heavy bass lines, a synchronous motor instantly draws more current and supplies more torque to the platter. This makes the controversial matter of stylus drag a non-issue. Because of this behavior, this type of motor does not need any form of servo circuit to control the speed when fed the proper power.

So contrary to the statement by Richardkrebs above, AC synchronous motors lock in and do not “phase lag”. If an AC synchronous motor sees additional load, it automatically draws more current and supplies more torque to the platter.
From the manufacturers website

This power is supplied via a sophisticated and very accurate power supply designed to give The Beat clean and consistent power with correct frequency, no matter how dirty your mains supply. This power supply also gives the audiophile another feature, adjustable motor torque. Every listener seems to enjoy a slightly different take on his music so The Beat lets you adjust the torque of the drive system.

In summary, the Kodo Beat TT includes:
High torque AC motor with no servos
Carefully designed platter weight (11kg) to match the high torque AC motor
Accurate power supply that provides the correct frequency to lock the AC motor regardless of the mains power
Adjustable torque controller to optimize the drive
1” bearing designed for loads to 100lbs+.

In comparison the Final Audio Parthenon, built in 1971 uses :
High torque AC motor with no servos
Carefully designed platter weight (22kg) to match the high torque AC motor
Accurate power supply that provides the correct frequency to lock the AC motor regardless of the mains power ( Sine & cosine wave generators and power amplifiers are used in the Final power supply )
Adjustable torque controller to optimize the drive ( prior to the Beat, the Final is the only TT I have seen with adjustable torque ).
1” bearing designed for loads to 100lbs+.

The differences between the Beat and the Final Audio Parthenon are :
The Beat utilises Magdrive, the Final Audio is thread drive.
The Beat appears to use a conventional T bearing ( that’s T for Topple in engineering terms ), whereas the Final uses an inverted bearing placing the centre of gravity of the platter well below the bearing point.

The closest equivalent for the Final Audio TT is its granddaughter - the Kondo Ginga at quoted retail prices of approximately US$80k

In my view the Kodo Beat is a well conceived design and at US$24000 appears to be a bargain.