KAB Audiophile Times
January 2005 - The Drive System - Page 1

Table Of Contents
Page 1......The Drive System
Page 2......The Tonearm
Page 3......The Mod Process
Page 4......Power Delivery
KAB Main 1200 Page

Wanna Know a Secret?
  Here's something you really must know:
Your favorite records were most likely mastered on a Technics SP-02 lathe turntable! It's true! click the link here now and see what google returns.
Search Technics SP-02
This is the product that set the course leading to the '1200; A direct drive motor that inaudibly senses and corrects for stylus drag.

Mastering houses needed a drive system that could inaudibly sense and correct for stylus drag.

  It's funny really, with CD, audiophiles decried 16 bits and demanded better. Now there is SACD and DVD-A.
But Analog hobbyists show little interest in the actual technology. I am betting that if they knew more about it, then they would demand more from it.

  People often ask what might have happened if all the money for CD was applied to analog? Well, something just like that happened when Technics formed the Special Products Group. Their work produced the SP-02 and the SP series of transcription turntables finally culminating in the integrated Technics SL-1200!

  We will never again see a time like that when so much talent, technology and resources were brought together to solve a single problem. We are fortunate to have a product like the '1200 to remind us of this time. Has any other company shown so much dedication to the turntable? Click here biography.

Gone Without a Trace
  Todays audiophile companies do not have the resources that Matsushita had in the late '70's. That is the main reason you do not see technology applied to todays turntables. The money required to design and produce application specific integrated circuits, casting molds, machining centers... man that takes a large bankroll! [Take the '1200 factory tour] And you need a large market to justify it. Todays "new age" audiophile industry has tried to produce direct drive 'tables; but always found the cost prohibitively high. The latest entry selling for nearly $20,000! It is a technology best left to the giants.

A Question of Time
  We've all heard the condemnation about how direct drives fidget and hunt for speed. It remains the most popularly stated myth today. So I put a 'scope on the 1200's internal self validating frequency generator and had a look for myself.

1200 Motor & Generator Coil

But 'lo and behold this direct drive motor doesn't hunt or fidget at all, just a steady sine wave is displayed. Turns out the '1200 is one of the few designs that uses a linear detection scheme. That means that corrections are only made when necessary and without rotational delays. [To be fair, there are some direct drive designs that make corrections only once per revolution. Thus lending some credibility to the "fidget" criticism. But then, those players do not achieve wow and flutter numbers of 0.01% ! They are usually 0.2%].

Some magazines have talked about early direct drive tables making corrections at 3000hz. I am not sure you could affect the speed of a 4 pound rotating mass that quickly! But a review of the original SL1200 schematic shows the time constant of the speed integrator to be about 1 second or about half of a platter revolution at 33.33RPM. The SL-1200 MK2 speed integrator has a time constant of 300ms or 1/6th of a revolution at 33.33RPM.

Close up of Generator Coil
  So when the '1200 needs to make a correction it is made gradually and in harmony with the flywheel effect of the 5 lb damped platter. In other words, the speed stays stable regardless of dynamic and static stylus drag. No more choking off of dynamics nor is there the wavering instability that follows loud crescendos. With an SP-02 on the cutting end and a '1200 on the playback end, the time domain "chain of custody" between master and playback is preserved.

With the '1200, the time domain "chain of custody" between master and playback is preserved.

  Myth #2: Direct drives are criticized for noise, but in fact are very quiet. some 20dB quieter than many belt drives. This is because the motor delivers its power to the most rigid part of the platter- the spindle, rotates at actual speed, applies power evenly without the side drag of a belt, and unlike most other drive systems, the power factor is infinitely variable.
The 1200 motor starts up fast drawing 200mA of current but quickly glides down to an operating current of just 10mA. With a rumble figure of -80dB, Speed accuracy of 0.005% and Wow & Flutter of 0.01%, it should be clear to all concerned that this is an industry standard; Something to be admired, not ignored.

The '1200 is an industry standard. Something to be admired, not ignored.

  Now you know a little about the '1200, come see how KAB makes it even better.
Click Here to Build Your Own KAB Custom '1200.

If Form Follows Function, So Then Music Follows Precision.
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