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The DMD drive is supplied with an umbilical cord that connects to the Low Voltage Motors used in the PolyTable, AR Upgrade, Heirloom and other Merrill products.
DMD with motor and pulley.Replacement for AR original motor. DMD $790.00 Motor $185.00 Package supplied with single sheave pulley
DMD Digital Motor Drive Made in the USA
Any turntable that has fixed speed (no manual variation) cannot retain speed accurately under all temperature, and humidity conditions The expansion / contraction coefficients of the drive materials will vary with the environment.A variable speed control solves this problem. The result is the retention of accurate pitch.The AC line power is contaminated with multi-frequency trash. Direct line coupled motors will suffer noise problems and can have speed-accuracy issues. Without a buffer, this trash is fed directly into the motor and is coupled into the drive system and record support platter. A properly designed motor drive will totally isolate the turntable drive system from this trash and allow the motor to run smoothly. This will help to eliminate the clouding of micro level information and lead to improved resolution culminating in better imaging, detail and musical realism. Unlike a DC motor where speed is feedback-controlled and is susceptible to servo hunting, a synchronous motor is frequency controlled and is more desirable for turntable drive. An aftermarket add-on motor drive system that produces power line voltage and utilizes a receptacle that the table plugs into is not as effective, the reason is the synchronous motor phase shift capacitor is still in use. This capacitor renders not a true 90-degree phase shift, adding impulse noise (motor does not run as smooth).
The Digital Motor Drive uses a regulated DC power supply powering a microprocessor, employing crystal-controlled adjustable dual oscillators for sine and cosine drive (true 90-degree phase shift). The low distortion precision sine wave dual oscillators drive two high power low distortion amplifiers that power the motor windings. This allows absolute total isolation from the power line. Speed sweep is plus or minus 2 percent. The turntable speed is checked with an onboard strobe light driven by a short pulse crystal - controlled square wave oscillator. Speed accuracy is three parts per million. Touch button logic control is employed. (On-Off and Speed Select) The Digital Motor Drive System is the most advanced drive system available.
The Digital Motor Drive uses a regulated DC power supply powering a microprocessor, employing crystal-controlled adjustable dual oscillators for sine and cosine drive (true 90-degree phase shift). The low distortion precision sine wave dual oscillators drive two high power low distortion amplifiers that power the motor windings. This allows absolute total isolation from the power line. Speed sweep is plus or minus 2 percent. The turntable speed is checked with an onboard strobe light driven by a short pulse crystal - controlled square wave oscillator. Speed accuracy is three parts per million. Touch button logic control is employed. (On-Off and Speed Select) The Digital Motor Drive System is the most advanced drive system available.