For what it’s worth when I purchased an extruder upgrade I had to get a new motor. The motor on my Ender 3 pro had a press fit gear on the motor arm and it was too short to fit the dual gear extruder (I did manage to get the press fit off only to realize the arm was too short).

If you’re able to order from Amazon, or a similar store with a decent return or exchange policy, I’d just get what you think you will need and return or exchange as necessary.

It seems to be coming predominantly from the hot end / extruder assembly. I have seen that various folks have resonance issues on this printer, so I’ll see if I can track down any more of those fixes. I did try the side panels off, loosen one of the screws, move the head around, retighten the screw thing, but that doesn’t seem to have made any difference. So I guess the gantry is square but something is causing resonance in the print head.

I can’t believe it would be the extruder, but I am a little curious about it since it also seems to have some odd extrusion effects (essentially like what I’d imagine it would look like when you “skip” over a surface by dragging something along; little splots, then thin, then little splots, but almost imperceptible due to the very high frequency of the micro stutters — first layers look almost flawless too so not really sure what the deal is).

Oh that’s interesting. I wonder if it’s a resonance thing / something a little loose. Maybe I’ll try retensioning the belts and see if that helps. If anything works I’ll mention it, just in case it’s related to your buzzing too!

Also, I am planning on purchasing some more hyper PLA to see if I can observe the same buzzing with that filament. I can’t imagine the filament type would cause the buzzing, but strange things do happen. Will report back here with any findings on that, but if anyone else has any thoughts in the meantime on this buzzing, I’m very keen to hear them!

Ah this sounds interesting. If I ever get around to taking the bottom plate off, I’m definitely going to check that out. The only other idea I had was to get metal shim washers and put them below the stand-off mounts for the bed, but I was worried it would befuddle the strain gauges somehow.

Ah I see, thanks very much for replying with this info! That actually makes a fair bit of sense. Little bit unfortunate, as I think the bottom plate with adjustments is quite cumbersome but more importantly difficult to get correct. I may just get some foil tape to shim for now, but will keep thinking of other solutions also.

Thanks again for the response!