High quality AC turntable motor

It seems to me that some of the posters here have forgotten some of their Trig. A complete sine wave cycle is 360 degrees. As the previous poster stated one set of field coils is driven by the primary AC current and the other with a AC current 90 degrees out of phase. This phase shift is usually accomplished with a capacitor (the current though a capacitor is 90 degrees out of phase with the voltage across it). Now, a sine wave generator with TWO amplifiers (thus two outputs), one 90 degrees out of phase, with the ability to "trim" the phase angle between the two has the ability to null out almost all motor vibrations. This is a distinct advantage over those sine wave generators with just one output. I own a Nottingham Wave Mechanic. I recently had it open to replace an output transistor that failed (it doesn't do too well with a single ended output stage). There is NOTHING special here. If the parts cost more than $125 I'd be surprised. Yet it retails for something north of $1200. They don't call us Audiofools for nothing. That's one reason I'm committed to DIY. Kevin's kit should provide a lot more "bang for the buck". The OEM power supplies are usually nothing more than an oscillator, a cheap amplifier and a transformer to boost the voltage output of the amp to 120V.

It would also seem that the manufacturer has taken phase into consideration in the manufacturer of the motor. If it runs from a wall socket, then it should be a matter of adjusting the voltage and alternating speed.

Hi all,

I am reading this thread with interest. The technical knowledge of some here, amazes me.

Having upgraded my turntable system to a three motor controller:
http://www.axissaudio.com/turntables/KM3.htm

In this German webpage, they discuss another turntable controller with amazing results. Seems like a real bargain compared to other controllers. http://www.frank-landmesser.de/hoer_analog_netzteil.html

I am very happy with the speed accuracy of this type of motor controller.

Still settling into our new house after our move back to the US from a lengthy tour of Europe.

Ciao,
Audioquest4life

Bpoletti, turntables that use AC are of the synchronous variety. Their speed is determined by the frequency of the AC, not it's voltage. The way AC line voltage bounces around a motor that depended on it for speed regulation would do a lousy job. See: http://en.wikipedia.org/wiki/Synchronous_motor
All this talk about phase has to do with reducing motor vibration, not speed regulation per say. Vibration can add a form of frequency modulated distortion, a form of analog "jitter" if you will.

What John wrote of the Notts controller is also largely true of the other best known tt controllers, namely that they do not do true phase splitting. Yet there are obvious benefits nevertheless. I am on the wait list for mark Kelly's controller, which will also do phase splitting, a la the KK one.