Description of the linear tracking turntable.
Posted by Ben Lamb -
I built this turntable a couple of years ago when experimenting with Linear tracking arms and I still use it as a demonstrator and point of reference. It is a simple design with a platter directly driven by a low voltage AC synchronous motor. The bearing has a 10mm stainless shaft running a silicon nitride ball on a removable thrustplate. The Acrylic plinth runs on three isofeet which isolate it from external vibation. The motor is driven by my Perfect Sine system which delivers a phase locked sine/cosine waveform to drive the motor. The motors speed can be calibrated and the system offers full electronic speed control.
The tonearm is a linear tracking or tangential tracking air bearing system. The system uses an airpump housed in a sound proofed enclosure to cause minimum disturbance to the user. The tonearm is very short and pivots on a pair of high specification bearings using a carbon fibre shaft and cueing mechanism. The turntable has been very reliable over the years and is a good one to fall back on for comparisons because everything in its design is tried and tested. It is good to have a solid system when testing out experimental prototypes.