Equatorial Motor Controller

The mains power entering your home is not clean. It is contaminated by the aggregate electromagnetic signature of every device on the grid — every refrigerator compressor, every dimmer switch, every charging phone. This contamination rides on the AC waveform as harmonic distortion, frequency drift, and voltage sag. Your turntable motor is a synchronous device: its speed is locked to the frequency of the AC supply. When that frequency wanders, so does the platter. The Equatorial Motor Controller eliminates this dependency entirely by regenerating the AC power supply from scratch, using a quartz-locked oscillator as its sole frequency reference.

The quartz reference is not merely temperature-compensated — it is oven-stabilised, held at a constant 72°C inside a thermally insulated chamber within the chassis. This eliminates the frequency drift that affects ordinary quartz oscillators as room temperature changes throughout the day. The regenerated sine wave achieves total harmonic distortion below 0.002% and frequency stability of ±0.0001%, which translates to speed accuracy that exceeds the measurement capability of any commercially available wow-and-flutter meter. The front panel displays platter speed to six decimal places: 33.333333 RPM. If you cannot measure it, you cannot control it. And if you cannot control it, you cannot claim it is correct.

A front-panel rotary encoder allows speed fine adjustment in increments of ±0.01 RPM, for those who have determined through careful measurement that their preferred pressing sounds most correct at a speed slightly different from the nominal standard. This is not a pitch control. It is a precision instrument for compensating the accumulated speed errors of the mastering lathe, the cutting head, and the stamper — none of which were operating at six-decimal accuracy. The controller provides two outputs: one for the motor drive and one auxiliary output for powering peripheral devices that benefit from regenerated AC, such as phono stages or preamps. Factory-set for either 110V or 230V operation.