Do the add-on noise reduction boards (variously called Schottky diodes, flyback diodes, noise filters) installed ahead of the stepper motors really improve print quality on FDM printers? I installed them on X and Y axes and can see no difference.

  • $\begingroup$ They'll stop your components from dying, they won't do anything for quality itself. $\endgroup$
    – Mast
    May 21 at 21:19
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    $\begingroup$ If you don't have DRV8825 drivers, you would not see any difference, see this answer. $\endgroup$
    – 0scar
    May 21 at 22:22

1 Answer 1


Flyback diodes aren't there to improve quality. They are there to )protect components the stepper connects to when the stepper stops. Motors store energy in inductors, and when power is dropped that energy goes back into the source driving them, which can damage equipment. Modern stepper drivers typically already account for that and are designed either with such diodes already included, or use a design that doesn't require them.

If anything, it might HURT performance with some drivers, as described in the article TL-Smoothers, Do They Make Sense?

  • $\begingroup$ Classic motor control design includes flyback diodes and capacitors to respectively snub and spread the back EMF spike from the motor windings. I can only think adding diodes to an existing controller are only needed if they thought caps were good enough and left out the diodes. $\endgroup$
    – user10489
    May 30 at 19:29
  • $\begingroup$ I guess you can't believe everything you read in the product description- "Pack of 4pcs TL-Smoother V1.0 Addon Modules for Pattern Elimination Motor Clipping Filter 3D Printer Stepper Motor Drivers". $\endgroup$
    – allardjd
    May 31 at 0:03
  • $\begingroup$ @allardjd apparently they did help with actual issues with DRV8825 stepper drivers - but that was due to a flaw in that specific type of driver, and not relevant for other newer types of stepper drivers. $\endgroup$
    – Grant
    May 31 at 13:14

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