FLUANCE RT85 Turntable Motor Humming

Motor Isolation Grommet Set

The RT85 motor is suspended by rubber grommets designed to decouple the motor's kinetic energy from the solid wood plinth. If these grommets perish or are improperly seated, the motor's operational vibration is transmitted through the chassis to the cartridge, resulting in an audible low-frequency hum. Replacing these restores the damping coefficient required to isolate the transducer from the drive system.

Replacement DC Servo Motor

Internal bearing wear or a localized short in the motor windings can cause an increase in electromagnetic noise and physical vibration. If the hum is present and originates from the motor housing itself regardless of isolation, the internal lubrication has likely failed or the servo-controller is struggling to maintain a steady RPM, causing torque ripple hum.

Grounding Wire (Phono Ground)

While often confused with mechanical hum, an electrical hum occurs if there is a potential difference between the turntable's internal shielding and the preamp. A replacement high-conductivity ground wire ensures the tonearm and motor shield are properly bonded to the amplifier's ground plane, eliminating 60Hz inductive hum.