I would really appreciate it if someone with a H2 series printer (I just got the H2C) can test this out and tell me if theirs do the same. Here goes my issue:
I just got and set up my brand new H2C today. I did the full 1h:30min calibration, and I can still notice a weird humming/buzzing noise or coil whine when the tool head is in certain positions. It is very noticeable after the homing procedure when the printer is just idle. Sometimes it is accompanied by some electrical crackling noise.
It is always present right after homing. But if I move the toolhead even 1mm on the x/y axis it goes away. What is this?
Here is the video:
This is very annoying and you can hear it even from a few feet away with the door of the printer closed.Is this something to be expected? What should I do? I got in touch with support, and they told me it is indeed “a little unusual” and they will get back to me. They gave me a support ticket number.
This seems to be related to more than just the home position of the printer. Somehow it has something to do with the LED status bar from underneath it. It seems that when the printer gets in the home position two things happen:
1. some weird low humming noise (like a fan).
2. the coil whine that coincides with what the LED strip from under the heat bed does (as in slowly blinking off - coil whine gone - slowly blinking back on - coil whine is back).
If I move the tool head on the x/y axis the coilwhine is still present at first then fades away. the low hum noise goes away and the printer gets pretty much silent.
Here’s the video with everything included: home position, disabling status light, moving the axis, hum noise, enabling the status light back and getting the coil whine back:
What is going on? Can you PLEASE test this so I know if this happens on other H2 printers or if this is an isolated occurrence on mine. This is brand new, I didn’t even get to print yet.
Sadly I already tried doing that, a couple of time actually. It didn’t help when idle. Did you also have the idle problem and it got solved with the motors calibration? I even tried reverting back to an older firmware.
I am no even sure that the motors are the problem anymore. I mean, I guess the hum might come from the motors, but at least that’s constant. The real problem is the LED strip that produces the coil whine as that is so lound you can hear it anywhere in the room, even with the printer’s door closed and it varies based on what the LED strip is doing.
Hello, it seems you are experiencing the following problem:
The symptoms are as follows:
The noise occurs only when the printer is in standby mode after step motor moved (idle).
It starts immediately after the printer completes the homing process and the motor stops moving.
The sound is a continuous, high-pitched buzzing or humming, likely coming from the stepper motor.
The noise stops completely as soon as the motor starts moving (e.g., during printing or any movement command).
The noise also stops when the motor current is released, allowing the print head to be moved freely by hand.
To explain, Inside the printer there’s a stepper motor that rotates to move the print head. This motor is continuously supplied with current to hold its fixed position even when stationary. The problem you’re currently experiencing is the noise that occurs during this current supply process.
Fortunately, it’s not a hardware issue, and Bambu Lab is already aware of the problem. I reported this issue to Bambu Lab in December 2025, and since there’s been no response so far, it’s likely the problem still hasn’t been resolved.
The ticket number for my inquiry about this issue is US251206562001. When you contact the support team, passing along this ticket number may help them look into the problem more easily
Thank you for your reply! I did, in fact, see your post from way back then as I was doing my research.
Unfortunately, at least in my case, it does not seem to be from the stepper motors. If I power on the device, the head is in the home position, no coil whine, no hum. I then proceed to home the printer again. I can hear the coil whine starting. A fan-like humming noise also starts.. The printer stops the homing procedure. The coil whine and the hum are still there. You can watch the homing procedure of my printer here:
If I turn the LED strip light indicator off, the coil whine is still there but much, much quieter. (Also, when the LED is on, the coil whine corresponds to the LED blinking - goes away when LED is off, comes back when it blinks on). With the LED strip light indicator off, you cannot hear the same coil whine loud buzzing as before during the home procedure or after. You can still hear the hum noise.
Here is a video with the LED strip light indicator from under the heat bed turned off:
What’s interesting is that after this second homing procedure with the LED turned off, I can move the tool head manually from the screen and in certain positions everything turns quiet (you can see this in the later parts of the last video linked in this reply). This leads me to believe it is a combination of whatever rail on the PSU the LED is pulling from, as well as the servos and the PSU. This sounds like an electrical issue to me. The printer is brand new, and I only completed the setup yesterday.. This should not be happening. I did compare and consult with a bunch of guys in the BambuLab Discord channel and they confirmed this is not present on their H2 machines. A guy even shared a video of his printer (also a H2C) and it was dead silent.
One thing you need to check is whether noise still occurs even when the printer head can be moved by hand (immediately after turning the printer off and on, or after stopping printing).
Depending on the device, hardware variations that occur within the normal range during the manufacturing process may cause some units to produce more of this hardware noise than others. To compensate for noise caused by these hardware variations, Bambu Lab provides a motor noise calibration. However, the noise currently occurring is not noise generated during motor rotation, but rather noise generated during the current supply that maintains a static position. This is likely why the current motor noise calibration feature cannot correct this noise.
Additionally, the form and magnitude of the noise can differ slightly between hardware units (for example, your printer produces more severe noise when the LEDs draw power, whereas in my case the problem occurs regardless of LED power consumption )
I honestly believe that what we got in our printers is not the norm and there are actually issues with both of our units (my H2C and your H2S).
Try turning off the status LED completly from the settings and take another video if you can. I do not know if you did this previously, but it is worth a try.
I think the issue is electrical, mostly regarding the PSU unit and not the servos. In my case I can get all the noise away and have her silent if I just move the tool head around. In certain positions it will go silent. This tells me it is not the servos, as the servos should still be engaged to hold position in those moments. (you can go to this video: https://www.youtube.com/watch?v=NEhGsFyelmY at ~1:47 and you will see it is actually silent after moving the tool head)
It has to be something else. I am honestly not looking forward to do any more tinkering to find out. I will just go ahead and ask for a replacement for the unit.
Since this issue doesn’t affect print quality or product usability, it seems Bambu Lab has pushed it down their priority list.
Does the noise continue even when voltage to the motor is cut off—that is, when the print head isn’t being controlled by the device? Right after you power-cycle the printer, or after stopping a print, voltage to the motor is cut off until the next movement command, and you can grab and move the head by hand. If no high-frequency noise occurs in this state, then it’s almost certainly a stepper motor power noise issue.
If you file a ticket for this, I’d really appreciate it if you could share the outcome with me :))
++ I just looked at the part you added! Stepper motor noise from holding current can vary depending on the current microstep position. At certain microstep positions, the chopping of the two coils can overlap or cancel out in phase, making the noise more pronounced only at specific positions. In the part of the video you mentioned that some noise is still audible even after the position was moved.
The reason I do NOT think it is servo related is actually the way I found out it is the LED strip in my case:
I was doing research on my computer with the printer behind me just leaving it to whine. Then, all of a sudden, it stops. I turned and realized the reason it stopped was because it went into standby mode or sleep mode, or whatever it is called (the display turned off and the LED bar turned off, but the LED flood lights were still on).
Then when I touched the display it immediately turned back on along with the LED bar and the whine came back. I do not see how this could be servo related. I then proceeded to do further testing and I remembered you could disable the LED bar completely from the settings. As soon as I did that the LOUD buzzing noise was gone. So at least I think that the coil whine is somehow related to the LED light too.
I sure will! Thank you for the replies. Hope we both get to the bottom of this, because I wish I could get a printer as silent as some that were shared with me through videos this evening.
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