Hi Irving2008,

The glitching is random, and occurs consistently at any speed lower than 8KHz. There is no bad point, they are all equally glitchy until about 8KHz where it starts to smooth out. Above 8KHz it never glitches.

Note that I'm not actually connected to a cnc machine at the moment to resolve this. There is just the 33v power supply, system3 board, one stepper motor, and the function generator. I've disconnected limits, estops etc. There is no load on the stepper and it is still glitching in the same way as when connected to the machine. By the way it sounds I don't think that this is a resonance issue, more like an electrical spike or interference type problem, but I'm open to try all ideas.

I've got 2off 3Nm motors (Arc Euro) which both glitch in the same way, and have different length wires, and one 1.8Nm motor (DIYCNC) which also glitches in the same way and has different length wires again.

I think the best thing for me to do is try and get a video posted so you can see the set up and hear the results of different speeds. Bare with me, never posted video before!

Thanks for your continued support. Determined to resolve this one . . .
Barry