Why Platter Mass Matters: Run-Down Time Explained

Run-down time is one of the most revealing yet overlooked turntable specs. It measures how many seconds the platter keeps spinning after you switch off the motor. A longer run-down means a heavier platter and lower-friction bearing — and that translates directly into better speed stability.

What Run-Down Time Tells You

When the motor stops, the platter coasts on its own inertia. A 300mm brass platter may spin for 80 seconds or more; a light aluminium platter might stop in under 30. The number tells you how much rotational mass is smoothing out the tiny speed variations from the motor.

Mass and Speed Stability

Heavier platters resist changes in speed. When the stylus drags through a loud passage, a heavy platter barely slows; a light platter dips more. This is why direct-drive decks with heavy brass platters and belt-drive decks with acrylic or brass platters both chase mass.

Bearing Quality

Run-down also reflects bearing friction. A well-polished, well-lubricated bearing lets the platter spin freely; a worn or dry bearing drags it to a stop quickly. Periodic bearing service keeps run-down long.

What to Look For

For audiophile listening, look for run-down times of 60 seconds or more. oneplusone direct-drive decks reach 80 seconds; our belt-drive acrylic and brass platters reach 72 to 80 seconds. The number is not the whole story, but it is a strong, honest indicator of build quality.