High frequency acoustic noise issue  

High frequency acoustic noise issue

Hello

I have had issues with my new MK3S+ printer. When the steppermotors are initialized and running the power supply give off a very loud high frequency acoustic noise, 15 kHz to 22+ kHz. This is probably not audible by most people due to the high frequency.

I have received fantastic support from Prusa to return my printer, no issues there. But i want to know if my PSU was a one off or if this is a common feature of this model before i order a new one (MK4)?

I hope some users have the possibility to measure the acoustic frequency response of your printers while in use according to the following procedure:

Download an FFT app of your choice. Suggestion "Spectrum Analyzer" by keuwlsoft, but any FFT app should work. Start the app and set sampling frequency as high as possible, minimum 44 kHz. Start a print on the printer (or actuate stepper motors using pronterface) and hold the phone close to the power supply and take a screenshot.
https://play.google.com/store/apps/details?id=com.keuwl.spectrumanalyzer

This is what the FFT looks like from my printer, the small peaks around 0 dB are the steppermotor sound + fans and these are nice and quiet compared to the 20 dB peak at 18,5 kHz caused by the PSU.