Loud thumping noise when switching on Up2stream Amp2.1

I have a Shelly 1PM as smart plug connected to my Bedroom system with TV and Android TV box and Amp2.1

Does anyone know what cause this loud thumping noise when switching on the outlet? How can I eliminate this.?

@staxza are you using rc snubber for shelly?

No, but will try to get one. They don’t sell it where I am. I will have to get a generic one

@staxza Pay attention to the fact that it is 600V (just like the inscription on the copy in the picture), the specification description is not accurate!

I have tried to plug the amp into the outlet and it still make the same noise when powering on. Is there a way to fit something to the amps power supply to fix this?

Probably some kind of soft-start circuit can solve this matter.
I’m using a bit more complicated setup and this would be an overkill for you, but I have an upc1237 based speaker protection circuit which can handle this as well.

How about a 24v Adjustable Timer Delay Relay module between the PSU and the amp?

You could use a speaker delay board in series with your speaker leads, these will provide a 3 second delay after power on.